Danfoss Axial Piston 90 Service guide
Series 90
Axial Piston
Pumps and Motors
Service Manual
Series 90 Introduction
Introduction
Use of this Manual
This manual includes information for the normal operation, maintenance, and servicing of the Series 90 family
of hydrostatic pumps and motors.
Since dirt and contamination are the greatest enemies of
any type of hydraulic equipment, cleanliness requirements must be strictly adhered to. This is especially
important when changing the system filter and during
The manual also includes the description of the units and
adjustment and repair activities.
their individual components, troubleshooting information, adjustment instructions, and minor repair procedures. Unit warranty obligations should not be affected if
maintenance, adjustment, and minor repairs are performed according to the procedures described in this
For further information refer to Series 90 Technical
Information. For information about fluid requirements
refer to SAUER-SUNDSTRAND BLN 9887 or SDF (Id No.
697581).
manual.
A worldwide network of SAUER-SUNDSTRAND AuthoMany service and adjustment activities can be performed
without removing the unit from the vehicle or machine.
However, adequate access to the unit must be available,
and the unit must be thoroughly cleaned before beginning
maintenance, adjustment, or repair activities.
rized Service Centers is available should repairs be
needed. Contact any SAUER-SUNDSTRAND Autho-
rized Service Center for details. A list of all Service
Centers can be found in bulletin BLN-2-400527, or in
brochure SAW (Ident. No. 698266).
Safety Precautions
Observe the following safety precautions when using and servicing hydrostatic products.
Loss of Hydrostatic Braking Ability
WARNING
The loss of hydrostatic drive line power in any
mode of operation (e.g., forward, reverse, or "neutral" mode) may cause the loss of hydrostatic
braking capacity. A braking system, redundant to
the hydrostatic transmission must, therefore, be
provided which is adequate to stop and hold the
system should the condition develop.
S000 001E
Fluid under High Pressure
WARNING
Use caution when dealing with hydraulic fluid
under pressure. Escaping hydraulic fluid under
pressure can have sufficient force to penetrate
your skin causing serious injury. This fluid may
also be hot enough to burn. Serious infection or
reactions can develop if proper medical treatment is not administered immediately.
S000 003E
WARNING
Certain service procedures may require the vehicle/machine to be disabled (wheels raised off
the ground, work function disconnected, etc.)
while performing them in order to prevent injury
to the technician and bystanders.
S000 005E
Copyright 1987-1998, SAUER-SUNDSTRAND GmbH & Co.
All rights reserved. Contents subject to change.
2
Flammable Cleaning SolventsDisable Work Function
WARNING
Some cleaning solvents are flammable. To avoid
possible fire, do not use cleaning solvents in an
area where a source of ignition may be present.
S000 004E
S90MVCTCD
S90PVMFCD
Series 90 Contents
Contents
Introduction ......................................................................................................................................................................... 2
Use of this Manual ........................................................................................................................................................................................ 2
Safety Precautions ........................................................................................................................................................................................ 2
Functional Description ....................................................................................................................................................... 5
General Description and Cross Sectional Views ......................................................................................................................................... 5
Variable Displacement Pumps................................................................................................................................................................ 5
Fixed Displacement Motor ..................................................................................................................................................................... 5
Variable Displacement Motor.................................................................................................................................................................. 6
The System Circuit ....................................................................................................................................................................................... 7
The Basic Closed Circuit ........................................................................................................................................................................ 7
Case Drain and Heat Exchanger ........................................................................................................................................................... 7
Common Features of Pumps and Motors .................................................................................................................................................... 8
End Caps and Shafts ............................................................................................................................................................................. 8
Speed Sensors ....................................................................................................................................................................................... 8
Pump Features ............................................................................................................................................................................................. 9
Charge Pump .......................................................................................................................................................................................... 9
Charge Relief Valve................................................................................................................................................................................. 9
Multi-Function Valves .............................................................................................................................................................................. 9
Pressure Limiter and High Pressure Relief Valves ....................................................................................................................... 10
System Check Valves .................................................................................................................................................................... 10
Bypass Valves ................................................................................................................................................................................ 10
Displacement Limiters .......................................................................................................................................................................... 11
Auxiliary Mounting Pads ....................................................................................................................................................................... 11
Filtration Options ................................................................................................................................................................................... 11
Pressure Override (POR) - 180 Frame Size Only ............................................................................................................................. 12
Pump Control Options .......................................................................................................................................................................... 13
Manual Displacement Control (MDC) ........................................................................................................................................... 13
Hydraulic Displacement Control (HDC) ........................................................................................................................................ 13
Electric Displacement Control (EDC) ............................................................................................................................................ 14
Automotive Control (FBA II B) ....................................................................................................................................................... 14
3-Position (FNR) Electric Control .................................................................................................................................................. 14
Motor Features ........................................................................................................................................................................................... 15
Motor Loop Flushing Valve and Charge Relief Valve ........................................................................................................................... 15
Variable Motor Displacement Limiters.................................................................................................................................................. 15
Variable Motor Controls ........................................................................................................................................................................ 16
Hydraulic 2-Position Control .......................................................................................................................................................... 16
Electric 2-Position Control .............................................................................................................................................................. 16
Technical Specifications ..................................................................................................................................................17
General Specifications ................................................................................................................................................................................ 17
Circuit Diagrams ......................................................................................................................................................................................... 17
Hydraulic Parameters ................................................................................................................................................................................. 18
Size Specific Data ....................................................................................................................................................................................... 19
Pressure Measurement ................................................................................................................................................... 20
Required Tools ............................................................................................................................................................................................ 20
Port Locations and Pressure Gauge Installation ....................................................................................................................................... 20
Variable Pump ....................................................................................................................................................................................... 20
Fixed Motor ........................................................................................................................................................................................... 23
Variable Motor ....................................................................................................................................................................................... 24
Initial Start-Up Procedure ................................................................................................................................................25
Fluid and Filter Maintenance ........................................................................................................................................... 26
Troubleshooting ................................................................................................................................................................ 27
"NEUTRAL" Difficult or Impossible to Find ................................................................................................................................................. 27
System Operating Hot ................................................................................................................................................................................ 27
Transmission Operates Normally in One Direction Only .......................................................................................................................... 28
System Will Not Operate in Either Direction .............................................................................................................................................. 28
Low Motor Output Torque ........................................................................................................................................................................... 29
Improper Motor Output Speed .................................................................................................................................................................... 29
Excessive Noise and/or Vibration .............................................................................................................................................................. 30
System Response is Sluggish .................................................................................................................................................................... 30
3
Series 90 Contents
Inspections and Adjustments .........................................................................................................................................31
Pump Adjustments ...................................................................................................................................................................................... 31
Charge Pressure Relief Valve Adjustment ........................................................................................................................................... 31
Multi-Function Valve Pressure Adjustment .......................................................................................................................................... 33
Engaging the Bypass Function ............................................................................................................................................................ 35
Pressure Override (POR) Valve Pressure Adjustment (Option for 180 Frame Size) ....................................................................... 36
Displacement Limiter Adjustment ......................................................................................................................................................... 37
Pump Control Adjustments ......................................................................................................................................................................... 38
Standard Manual Displacement Control (MDC) Adjustment .............................................................................................................. 38
Non-Linear Manual Displacement Control (MDC) .............................................................................................................................. 39
MDC Neutral Start Switch (NSS) Adjustments .................................................................................................................................... 40
Hydraulic Displacement Control (HDC) and Electric Displacement Control (EDC) Adjustment ....................................................... 46
Motor Adjustments ...................................................................................................................................................................................... 48
Charge Relief Valve Adjustment ........................................................................................................................................................... 48
Displacement Limiter Adjustment (MV) ................................................................................................................................................ 49
Displacement Control Adjustments ...................................................................................................................................................... 49
Speed Sensor Adjustment .......................................................................................................................................................................... 50
Minor Repair Instructions ................................................................................................................................................ 51
Pump and Motor Minor Repair .................................................................................................................................................................... 53
Pump / Fitting Torques .......................................................................................................................................................................... 53
Shaft Seal and Shaft Replacement ...................................................................................................................................................... 54
Pump Minor Repairs ................................................................................................................................................................................... 56
Multi-Function Valve Cartridges ........................................................................................................................................................... 56
Pressure Override Valve (Option for 180 Frame Size)....................................................................................................................... 57
Charge Relief Valve ............................................................................................................................................................................... 57
Charge Pump - Remove ...................................................................................................................................................................... 58
Installing the Charge Pump .................................................................................................................................................................. 60
Auxiliary Pad Installation ....................................................................................................................................................................... 62
Auxiliary Pad Conversion ..................................................................................................................................................................... 63
Filtration Options ................................................................................................................................................................................... 64
Pump controls ....................................................................................................................................................................................... 65
Cover Plate ..................................................................................................................................................................................... 65
Manual Displacement Control (MDC) ........................................................................................................................................... 66
Solenoid Override Valve for MDC .................................................................................................................................................. 67
Solenoid Override Valve for MDC with Pressure Released Brake .............................................................................................. 67
Hydraulic and Electric Displacement Controls ............................................................................................................................. 68
Pressure Control Pilot (PCP) for Electric Displacement Control .................................................................................................. 68
3-Position (FNR) Electric Control .................................................................................................................................................. 69
Displacement Control Components ............................................................................................................................................... 69
Minor Repair - Motor ................................................................................................................................................................................... 71
Loop Flushing and Charge Relief Valves ............................................................................................................................................. 71
Variable Motor Displacement Limiters.................................................................................................................................................. 73
Variable Motor Controls............................................................................................................................................................................... 74
Electrohydraulic 2-Position Control (Types NA, NB, NC, and ND) ..................................................................................................... 74
Hydraulic 2-Position Control (Type PT) ............................................................................................................................................... 74
Control Plugs ........................................................................................................................................................................................ 74
Variable Motor Control Orifices ............................................................................................................................................................ 75
Speed Sensor .............................................................................................................................................................................................. 77
Exploded View Parts Drawings / Parts Lists .................................................................................................................. 78
Variable Pumps ........................................................................................................................................................................................... 78
Minor Repair Parts ................................................................................................................................................................................ 78
Parts List ............................................................................................................................................................................................... 79
Variable Pump Controls ........................................................................................................................................................................ 80
Control Parts List .................................................................................................................................................................................. 81
Filter and Options ................................................................................................................................................................................. 82
Parts List Filter and Options ................................................................................................................................................................. 83
Name Plates ......................................................................................................................................................................................... 83
Fixed Motor ................................................................................................................................................................................................. 84
Minor Repair Parts ................................................................................................................................................................................ 84
Parts List ............................................................................................................................................................................................... 85
Name Plates ......................................................................................................................................................................................... 85
Variable Motor.............................................................................................................................................................................................. 86
Minor Repair Parts ................................................................................................................................................................................ 86
Parts List ............................................................................................................................................................................................... 87
Name Plate ............................................................................................................................................................................................ 87
4
Series 90 Functional Description
Functional Description
This section describes the operation of pumps, motors, and their various serviceable features. It is a useful reference for
readers unfamiliar with the functioning of a specific system.
General Description and Cross Sectional Views
Variable Displacement Pumps
The Variable Displacement Pump (PV) is designed to
convert an input torque into hydraulic power. The input
shaft turns the pump cylinder which contains a ring of
pistons. The pistons run against a tilted plate, called the
swashplate. This causes the pistons to compress the
hydraulic fluid which imparts the input energy into the
hydraulic fluid. The high pressure fluid is then ported out
to provide power to a remote function.
The swashplate angle can be varied by the control piston.
Altering the swashplate angle varies the displacement of
fluid in a given revolution of the input shaft.
Series 90 Variable Displacement Pump (PV)
Slider Block
Cradle Hold Down
Servo Arm
Servo Piston
Servo Valve
F000 539
Feed Back
Cradle Bearing
Fixed Displacement Motor
The Fixed Displacement Motor (MF) is designed to
convert an input of hydraulic power into an output torque.
It operates in the reverse manner of the pump. The high
pressure hydraulic fluid enters through the input port. The
fluid pressure builds behind the pistons causing them to
move down the swashplate (the path of least resistance).
As the piston returns up the swashplate again, the fluid is
allowed to exit through the exit port. The spinning pistons
are housed in a cylinder which is connected to the output
shaft. The output torque can be applied to a mechanical
function.
Charge Pump
Cradle Leveler
Cradle
Cradle Guide
Series 90 PV Cross Section
Series 90 Fixed Displacement Motor (MF)
P001 413E
90000347
5
Series 90 Functional Description
In the Fixed Displacement Motor the "swashplate" is
Loop Flushing Valve
Valve Plate
Piston
Roller Bearing
Output Shaft
fixed, so any variation in motor speed and torque must be
made by the input mechanism, i.e. the pump.
End Cap
Cylinder Block
Fixed Swashplate
Series 90 MF Cross Section
Series 90 Variable Displacement Motor (MV)
End Cap
Valve Plate
Piston
Roller Bearing
90000190E
90000348
Output Shaft
Variable Displacement Motor
The Variable Displacement Motor (MV) operates in the
same manner as the fixed motor. However, its swashplate
is not fixed; it can be switched between minimum and
maximum angle to amplify torque or speed like the
Variable Displacement Pump.
Minimum Angle
Control Piston
Cradle Swashplate
"A"
Cylinder Block
6
Cradle Swashplate
Electric 2-Position Control (optional)
"A"
Series 90 MV Cross Section
Maximum Angle
Control Piston
Partial Section "A-A"
Cradle Swashplate in Full
Displacement Position
90000234E
Series 90 Functional Description
The System Circuit
Control Handle
Variable
Displacement
Pump
Input
Shaft
Pump Swashplate
Displacement Control Valve
Heat Exchanger
Bypass Valve
to Pump
Case
Reservoir
Vacuum Gauge
Purge Relief Valve
Motor Swashplate
Loop Flushing Valve
Orificed
Check Valve
Servo Control
Cylinder
Servo Control
Cylinder
Heat Exchanger
Multi-Function
Valve
Servo Pres.
Relief Valve
Charge Pressure
Relief Valve
Charge Pump
Multi-Function Valve
Pump Fixed Motor
Circuit Diagram for Series 90 PV and 90 MF
System loop
Case drain fluid
System loop
Control fluid
Suction line
Fixed Displacement
Motor
Output Shaft
(low pressure)
(high pressure)
90000800E
The Basic Closed Circuit
The main ports of the pump are connected by hydraulic
lines to the main ports of the motor. Fluid flows, in either
direction, from the pump to the motor then back to the
pump in this closed circuit. Either of the hydraulic lines
can be under high pressure. In pumping mode the
position of the pump swashplate determines which line is
high pressure as well as the direction of fluid flow.
Case Drain and Heat Exchanger
The pump and motor require case drain lines to remove
hot fluid from the system. The motor should be drained
from its topmost drain port to ensure the case remains full
of fluid. The motor case drain can then be connected to
the lower drain port on the pump housing and out the top
most port. A heat exchanger, with a bypass valve, is
required to cool the case drain fluid before it returns to the
reservoir.
Reservoir
Input
PV
Flow (Bi-directional)
Basic Closed Circuit
MF
Output
Case Drain Line
90000803E
7
Series 90 Functional Description
Common Features of Pumps and Motors
End Caps and Shafts
Series 90 pumps and motors can be supplied with a
variety of end caps and shafts to allow for almost any
configuration. For pumps, end caps are available with
system ports on either side ("side ports") or both ports on
one side ("twin ports"). Motors have end caps with ports
on the face of the end cap ("axial ports") or both ports on
one side ("twin ports"). See the Series 90 Technical
Information manuals (BLN-10029 and BLN-10030) or the
Series 90 Price Book (BLN-2-40588) for information on
available options.
Removing the end cap will void the warranty on a
Series 90 pump or motor.
Speed Sensors
Speed Sensor
An optional speed sensor can be installed on Series 90
pumps and motors to provide unit speed information. The
sensor reads a magnetic ring wrapped about the unit's
cylinder. See the corresponding Section to locate, install
and adjust the sensor.
90000810
8
Series 90 Functional Description
Pump Features
Charge Pump
The charge pump is necessary to supply cool fluid to the
system, to maintain positive pressure in the main system
loop, to provide pressure to operate the control system,
and to make up for internal leakage. Charge pressure
must be at its specified pressure under all conditions of
driving and braking to prevent damage to the transmission.
The charge pump is a fixed-displacement, gerotor type
pump installed in the variable displacement pump and
driven off the main pump shaft. Charge pressure is limited
by a relief valve.
The standard charge pump will be satisfactory for most
applications. However, if the charge pump sizes available
for the given main pump size are not adequate, a gear
pump may be mounted to the auxiliary mounting pad and
supply the required additional charge flow.
Charge Relief Valve
The charge relief valve on the pump serves to maintain
charge pressure at a designated level. A direct-acting
poppet valve relieves charge pressure whenever it surpasses a certain level. This level is nominally set referencing case pressure at 1500 rpm. This nominal setting
assumes the pump is in neutral (zero flow); in forward or
reverse charge pressure will be lower. The charge relief
valve setting is specified on the model code of the pump.
Multi-Function Valves
Case
Drain
Input
Line
90000243
PV with Charge Pump
Charge Relief Valve
System
Check
Valves
PV PF
Charge
Pump
Inlet Filter
Tank
90000804E
Pump Charge System
The multi-function valve incorporates
the system check valve,
the pressure limiter valve,
the high pressure relief valve and
the bypass valve
in a replaceable cartridge.
These functions are described separately. There are two
multi-function valve cartridges in each Series 90 pump to
handle functions in either direction. See corresponding
Sections for adjustments and repairs.
NOTE: Some multi-function valves do not include a
pressure limiter valve.
90000243
Multi-Function Valve
9
Series 90 Functional Description
Pressure Limiter and High Pressure Relief Valves
Pressure Limiter Housing
Pressure Limiter
Lock Nut
Pressure Limiter
Adjustment Screw
Bypass
Actuator
Cross Section of Multi-Function Valve
Servo Piston
Port "A"
Port "B"
Servo Piston
Pressure Limiter
Valve Poppet
To Control
Multi-Function Valve
Servo Pres.
Relief Valve
High Pressure
Relief / check
Valve Poppet
Bypass
Bypass
Adjustment
Check Valve
Poppet
90000806E
Charge Pressure
Relief Valve
Series 90 pumps are designed with a sequenced pressure limiting system and high pressure relief valves.
When the preset pressure is reached, the pressure limiter
system acts to rapidly destroke the pump so as to limit the
system pressure. For unusually rapid load application,
the high pressure relief valve acts to immediately limit
system pressure by cross-porting system flow to the low
pressure side of the loop. The pressure limiter valve acts
as the pilot for the high pressure relief valve spool. The
high pressure relief valve is sequenced to operate at
approximately 35 bar (500 psi) above the level that initiates the pressure limiter valve.
Both the pressure limiter sensing valves and relief valves
are built into the multi-function valves (see above).
NOTE: For some applications, such as dual path ve-
hicles, the pressure limiter function may be defeated so that only the high pressure relief valve
function remains.
System Check Valves
The system check valves allow pressurized flow from the
charge pump to enter the low pressure side of the loop
whenever system pressure dips below a certain level.
This is needed as the pump will generally lose system
pressure due to leakage and other factors. Since the
pump can operate in either direction, two system check
valves are used to direct the charge supply into the low
pressure lines. The system check valves are poppet
valves located in the multi-function valve assembly.
Bypass Valves
The bypass valves ("tow") can be operated when it is
desired to move the vehicle or mechanical function when
the pump is not running. The valve is opened by manually
resetting the valve position.
10
Multi-Function Valve
Circuit Diagram showing Pressure
Control Mechanism
90000801E
The bypass valves are built into the multi-function valves.
Series 90 Functional Description
Displacement Limiters
All Series 90 pumps are designed for optional mechanical
displacement (stroke) limiters. The maximum displacement of the pump can be limited in either direction.
The setting can be set as low as 0° in either direction.
For instructions on adjustment see corresponding Section.
Auxiliary Mounting Pads
Auxiliary mounting pads are available on all Series 90
pumps. SAE A through E mounts are available (availability varies by pump size). This pad is used for mounting
auxiliary hydraulic pumps and for mounting additional
Series 90 pumps to make tandem pumps. The pads allow
for full through-torque capability.
Filtration Options
All Series 90 pumps are available with provisions for
either suction or charge pressure filtration (integral or
remote mounted) to filter the fluid entering the charge
circuit.
Suction Filtration
The suction filter is placed in the circuit between the
reservoir and the inlet to the charge pump. When suction
filtration is used, a reducer fitting is placed in the charge
pressure gauge port (M3). Filtration devices of this type
are provided by the user.
Charge Pressure Filtration
90000244
PV with Displacement Limiters
90000242
PV with Auxillary Mounting Pad
90000243
PV with Suction Filtration
(No filtration device attached)
The pressure filter may be integrally mounted directly on
the pump or a filter may be remotely mounted for ease of
servicing.
A 125 µm screen, located in the reservoir or the charge
inlet line, is recommended when using this filtration
option.
PV with Integral Charge
90000246
Pump
PV with Remote Charge
90000247
Pump
11
Series 90 Functional Description
To Control
Pressure
Override Control Valve
Port "A"
Shuttle
Valve
Port "B"
Multi-Function Valve
POR-Valve (180 Frame Size only)
Multi-Function Valve
Charge Pressure
Relief Valve
Bypass
Adjustment
90000802E
Pressure Override (POR) - 180 Frame Size Only
The pressure override valve (POR) modulates the control
pressure to the displacement control to maintain a pump
displacement which will produce a system pressure level
less than or equal to the POR setting. For unusually rapid
load application, the high pressure relief valve function of
the multifunction valves is available to also limit the
pressure level.
The pressure override consists of a three-way normally
open valve which operates in series with the pump
displacement control. Control supply pressure is normally ported through the pressure override valve to the
displacement control valve for controlling the pump's
displacement. If the system demands a pressure above
the override setting, the POR valve will override the
control by reducing the control pressure supplied to the
displacement control. As the control pressure reduces,
the internal forces tending to rotate the swashplate
overcome the force of the servo pistons and allow the
pump's displacement to decrease.
12
Series 90 Functional Description
Pump Control Options
Manual Displacement Control (MDC)
The manual displacement control converts a mechanical input signal to a hydraulic signal using a spring- centered fourway servo valve. This valve ports hydraulic pressure to either side of a dual-acting servo piston. The servo piston rotates
the cradle swashplate through an angular rotation of ±17°, thus varying the pump’s displacement from full displacement
in one direction to full displacement in the opposite direction.
The MDC is designed so the angular position of the pump swashplate is proportional to the rotation of the control input
shaft.
Non-Linear MDC
The non-linear manual displacement control operates in
the same manner as the regular MDC except that it is
designed so the change in the angular position of the
pump swashplate
input shaft is rotated toward its maximum displacement
position.
Solenoid Override Valve for MDC
progressively
increases as the control
A solenoid override valve option (not shown here) is
available for MDC. This safety feature will return the
swashplate to zero displacement position when activated. The valve may be set in either a normally open or
normally closed mode.
Neutral Start Switch (NSS)
The neutral start switch is an optional feature available
with MDC. When connected properly with the vehicle’s
electrical system, the neutral start switch ensures that the
prime mover can be started only when the control is in a
neutral position.
Hydraulic Displacement Control (HDC)
The hydraulic displacement control uses a hydraulic input
signal to operate a spring-centered four-way servo valve.
This valve ports hydraulic pressure to either side of a
dual-acting servo piston. The servo piston rotates the
cradle swashplate through an angular rotation of ±17°,
thus varying the pump’s displacement from full displacement in one direction to full displacement in the opposite
direction. The HDC is designed so the angular position of
the pump swashplate is proportional to input pressure.
90000237
PV with Manual Displacement Control
90000239
PV with Manual Displacement Control and
Neutral Start Switch
PV with Hydraulic Displacement Control
90000240
13
Series 90 Functional Description
Electric Displacement Control (EDC)
The electric displacement control is similar to the hydraulic displacement control with the input signal pressure
controlled by a pressure control pilot (PCP) valve. The
PCP valve converts a DC electrical input signal to a
hydraulic signal which operates a spring- centered fourway servo valve. This valve ports hydraulic pressure to
either side of a dual-acting servo piston. The servo piston
rotates the cradle swashplate through an angular rotation
of ±17°, thus varying the pump’s displacement from full
displacement in one direction to full displacement in the
90000241
PV with Electric Displacement Control
opposite direction. The control is designed so the angular
position of the swashplate is proportional to the EDC
input.
Automotive Control (FBA II B)
Automotive Control allows a vehicle to be driven in a
manner similar to an automobile with an automatic transmission.
The Automotive Control includes a three-position electric
control to provide direction control.
PV with 3-Position (FNR) Electric Control
3-Position (FNR) Electric Control
This control utilizes a 12 or 24 VDC electrically operated
spool valve to port pressure to either side of the pump
displacement control piston. Energizing one of the solenoids will cause the pump to go to its maximum displacement in the corresponding direction.
All functions of the three-position (FNR) electric control
are preset at the factory.
90000354
14
Series 90 Functional Description
Charge Relief Valve
Loop Flushing Shuttle Valve
End Cap
Top of Motor
Motor Features
Motor Loop Flushing Valve and Charge Relief
Valve
All Series 90 motors are designed to accommodate a loop
flushing valve. The loop flushing valve is used in installations which require additional fluid to be removed from
the main hydraulic circuit because of transmission cooling requirements, or unusual circuits requiring additional
loop flushing to remove excessive contamination in the
high pressure circuit.
Loop Flushing Valve (MF)
A shuttle valve and charge relief valve are installed in the
motor end cap to provide the loop flushing function. The
shuttle valve provides a circuit between the low pressure
side of the closed loop and the charge relief valve in the
motor end cap.
The motor charge relief valve regulates the charge pressure level only when there is a pressure differential in the
main loop. The shuttle valve is spring centered to the
closed position so that no high pressure fluid is lost from
the circuit when reversing pressures.
90000248
For charge relief valve adjustment see corresponding
Section.
Variable Motor Displacement Limiters
All Series 90 variable motors include mechanical displacement (stroke) limiters. Both the maximum and minimum displacement of the motor can be limited.
The range of the settings is as follows:
muminiM
tnemecalpsiD
mumixaM
tnemecalpsiD
VM550VM570
3
mc04-91
3
ni4.2-2.1
%001-56%001-56
3
mc45-62
3
ni3.3-6.1
E152200T
90000238E
Motor Charge Relief Valve and Loop Flushing
Shuttle Valve
90000352
MV Maximum Displacement Limiter
(Minimum Displacement Limiters on opposite side)
15
Series 90 Functional Description
Variable Motor Controls
Hydraulic 2-Position Control
This control utilizes a hydraulically operated three-way
hydraulic valve to port system pressure to either of the
motor displacement control pistons. The motor is normally held at its maximum displacement. Supplying pilot
hydraulic pressure to the valve will cause the motor to go
to its minimum displacement.
90000350
MV with Hydraulic 2-Position Control
Electric 2-Position Control
This control utilizes an electric solenoid operated threeway hydraulic valve to port system pressure to either of
the motor displacement control pistons. The motor is
normally held at its maximum displacement. Energizing
the solenoid will cause the motor to go to its minimum
displacement.
16
90000351
MV with Electric 2-Position Control
Series 90 Technical Specifications
M2
B
L1
M1
A
L2
M3
Technical Specifications
General Specifications
Design
Variable Pumps and Motors: Axial piston pump of variable displacement, cradle swashplate design.
Fixed Motors: Axial piston motor with fixed displacement,
fixed swashplate design.
Type of Mounting (per SAE J744)
SAE flange, Size "B", 2 bolts,
SAE flange, Size "C and E", 4 bolts.
Cartridge flange, 2 bolts (for motor only).
Circuit Diagrams
Port Connections
(for details see chapter "Pressure Measurement")
Main pressure ports: SAE flange, Code 62,
Remaining ports: SAE straight thread O-ring boss.
Direction of Rotation
Clockwise or counterclockwise (motors are bi-directional)
Recommended Installation Position
Pump installation recommended with control position on
the top or side. Consult SAUER-SUNDSTRAND for nonconformance guidelines. The housing must always be
filled with hydraulic fluid.
L2
A
M3
M1
M5
M4
M3
X5
L1
S
A
M1
B
M2
B
L2
L1
MV with Electrohydraulic 2-Position
Control
Vg
max
M2
PV with Charge Pump and Manual
Displacement Control
MF
90000811
90000812
90000813
17
Series 90 Technical Specifications
Hydraulic Parameters
)1
egnaRerusserPmetsySrabisp
erusserPdetaR0240006
erusserPmumixaM0840696
muminiM04-]04-[tratsdloc,tnettimretni
detaR401]022[
mumixaM511]042[tnettimretni
E252200T
)1
C°]F°[
.tropniard
egnaRerutarepmeT
esacehtyllamron,tnioptsettohehttA
E600200T
muucaVtelnIpmuPegrahC
)ylnospmupno(
muucaVmuminiM
)suounitnoc(
sbarabgHni
7.001
gnirudmuucaVmuminiM
tratSdloC
2.052
)tnettimretnI(
erusserPesaCrabisp
)suounitnoC(mumixaM344
)tnettimretnI(
tratSdloCgnirudmumixaM
537
Hydraulic Fluid
Refer to SAUER-SUNDSTRAND BLN 9887 or SDF (Id
No. 697581). Also refer to publication ATI-E 9101 for
information relating to biogradable fluids.
ytisocsiV
egnargnitarepo
x
noitartlifnoitcusrof
x
erusserpegrahcrof
telnidednemmoceR
noitartliferusserp
mm2s/]SUS[
06-21]872-07[
ssenilnaelcdiulfderiuqeR
oitar-
oitar-
egrahcrofezisneercs
dnaleveLssenilnaelC βββββ
x
β
54-53
β
02-51
001 µ 521-m µm
,tnettimretni
tratsdloc
E010200T
oitaR-
31/81ssalC6044OSI
(57= β01≥ )2
(57= β01≥ )01
E700200T
muminiM7]94[tnettimretni
dednemmoceR
mumixaM0061]0057[
E352200T
level
dednemmoceR β
dednemmoceR β
noitartlif
E452200T
Cleanliness
Refer to SAUER-SUNDSTRAND Publications BLN 9887
or SDF (NO. 697581) and ATI-E 9201.
Refer to Series 90 technical information for definitions.
18
Series 90 Technical Specifications
Size Specific Data
Variable Displacement Pumps
noisnemiDVP030VP240VP550VP570VP001VP031VP081VP052
tnemecalpsiD
)mumixam(
deepSmuminiMnim
deepSdetaRnim
deepSmumixaMnim
deepSelbaniattamumixaM
tnemecalpsiD.xamta
taeuqroTlaciteroehT
tnemecalpsiD.xam
thgieW
)tinuesabylno(
Fixed and Variable Displacement Motors
3
mc
3
ni
1-
)mpr(005005005005005005005005
1-
)mpr(00240024009300630033001300620032
1-
)mpr(00640064052405930563004305820052
1-
nim
)mpr(00050005007400340004007305130572
rab/mN
gk
bl
03
38.1
84.0
isp0001/ni•fbl
092
82
26
24
65.2
76.0
083
43
57
55
53.3
88.0
035
04
88
57
75.4
91.1
037
94
801
001
01.6
95.1
078
86
051
031
39.7
70.2
0621
88
591
081
89.01
78.2
0571
631
003
052
52.51
79.3
3342
451
043
E752200T
tiehniEFM030FM240FM550FM570FM001FM031VM550VM570
3
)mumixam(tnemecalpsiD
)muminim(tnemecalpsiD
mumixamta
detaR
deeps
tnemecalpsid
muminimta
tnemecalpsid
mumixamta
mumixaM
deeps
tnemecalpsid
muminimta
tnemecalpsid
tadeepselbaniatta.xaM
tnemecalpsid.xam
.xamtaeuqrotlaciteroehT
mc
3
ni
3
mc
3
ni
1-
nim
)mpr(00240024009300630033001300930063
1-
nim
)mpr(------------00640524
1-
)mpr(00640064052405930563004305240593
nim
1-
nim
)mpr(------------00150074
1-
nim
)mpr(00050005007400340004007300740034
rab/mN
tnemecalpsid
tnemecalpsid
.xamrawolfmumixaM
rewoprenroc.xaM
thgieW
egnalF-EAS
thgieW
rotoMegdirtraC
nim/l
nim/lag
Wk
ph
gk
bl
gk
bl
03
38.1
24
65.2
55
53.3
57
75.4
001
01.6
031
39.7
------------9162
isp0001/ni•fbl
092
831
5.63
111
941
11
42
--
84.0
76.0
083
391
15
551
802
51
43
12
64
88.0
035
432
26
781
152
22
94
62
75
91.1
037
692
87
732
813
62
75
33
27
95.1
079
563
69
292
293
43
47
----
70.2
0621
244
711
453
574
54
99
55
53.3
88.0
035
432
26
422
003
93
68
04
88
57
75.4
91.1
037
692
87
282
873
44
89
64
101
E852200T
Refer to Series 90 technical information for definitions.
19
Series 90 Pressure Measurement
Pressure Measurement
Required Tools
The service procedures described in this manual for
Series 90 pumps and motors can be performed using
common mechanic's tools. Special tools, if required are
shown.
Port Locations and Pressure Gauge Installation
The following sections list the ports for each type of
hydraulic unit. The recommended pressure gauge and
fitting are also specified.
Variable Pump
troPnoitcnuF
1M
2M
3M
)6M(
4M
5M
erusserPmetsyS
"A"troP
erusserPmetsyS
"B"troP
erusserPegrahC
erusserPovreS
eziSeguaG
dna
gnittiF
isp00001rorab0001
gnir-O81-61/9
isp00001rorab0001
gnittifgnir-O81-61/9
isp0001rorab05
gnir-O81-61/9
isp0001rorab05
gnir-O81-61/9
E952200T
Pressure gauges should be calibrated frequently to ensure accuracy. Snubbers are recommended to protect
pressure gauges.
Outline drawings showing port locations follow the tables
below.
eziSeguaG
troPnoitcnuF
dna
gnittiF
1L
2L
1X
2X
3X
S
erusserPesaC
030
240
550
570
001
031gnir-O21-61/5-1
081
052
CDE/CDH
erusserPlortnoC
lortnoClanretxE
erusserP
telnIpmuPegrahC
030
240
550
570
001
031
081
052
isp001rorab01
gnir-O41-8/7
gnir-O21-61/1-1
gnir-O21-8/5-1
isp0001rorab05
gnir-O02-61/7
ro
gnir-O81-61/9
isp0001rorab05
gnir-O81-61/9
otnieeT,eguaGmuucaV
eniLtelnI
gnir-O21-61/1-1
gnir-O21-61/5-1
gnir-O21-8/5-1
tilpS-EAS2/1-1
egnalF
E062200T
20
Series 90 Pressure Measurement
Servo / Displacement
Cylinder Pressure
Gauge Port M4
Case Drain
Port L1
System Pressure
Port B
Servo / Displacement
Cylinder Pressure
Gauge Port M5
Top View
System Pressure
Gauge Port M2
Charge Inlet Pressure
System Pressure
Gauge Port M1
Carge Pump
Inlet Port S
System Pressure
Port B
System Pressure
Port A
Left Side View
Case Drain Port L2
90000814E
External Control Pressure
Supply Port X3
Speed Sensor
Charge Pressure
Gauge Port M3
Right Side View
PV with Side Port End Cap and Manual Displacement Control
90000815E
90000816E
21
Series 90 Pressure Measurement
Servo / Displacement
Cylinder Pressure
System Pressure
Gauge Port M2
System Pressure
Port B
Charge Pump Inlet
Port S
System Pressure
Port A
System Pressure
Gauge Port M1
Case Drain
Port L1
Case Drain Port L2
Top View
Left Side View
Gauge Port M4
Servo / Displacement
Cylinder Pressure
Gauge Port M5
Port E
(from filter)
Port D
(to filter)
Charge Pressure
Gauge Port M3
(after the filter)
PV with Twin Port End Cap and Manual Displacement Control
Charge Pressure
Gauge Port M3
Rear View
(after the filter)
Charge Pressure
Gauge Port M6
(before the filter)
Rear View
90000819E
90000820E
90000817E
90000818E
PV with Side Port End Cap and Remote Pressure Filtration PV with Side Port End Cap and Integral Pressure Filtration
22
Series 90 Pressure Measurement
Fixed Motor
troPnoitcnuF
1M
2M
3M
Charge Pressure
Gauge Port M3
eziSeguaG
dna
gnittiF
erusserPmetsyS
"A"troP
erusserPmetsyS
"B"troP
erusserPegrahC
System Pressure
Gauge Port M1
System Pressure
Gauge Port M2
isp00001rorab0001
gnir-O81-61/9
isp00001rorab0001
gnir-O81-61/9
isp0001rorab05
gnir-O81-61/9
E162200T
troPnoitcnuF
1L
2L
)erusserPesaC
030
240
550
570
001
031
Case Drain Port L1
eziSeguaG
dna
gnittiF
isp005rorab01
gnir-O41-8/7
gnir-O21-61/1-1
E262200T
Charge Pressure
Gauge Port M3
System Pressure Port A
Rear View
System Pressure
Gauge Port M1
System Pressure
Gauge Port M2
System Pressure Port A
Rear View
System Pressure Port B
MF with SAE Flange
System Pressure Port B
MF with Cartridge Flange
Case Drain Port L2
Left Side View
Left Side View
Speed Sensor
Case Drain Port L1
Speed Sensor
Case Drain Port L2
90000821E
23
Series 90 Pressure Measurement
Variable Motor
troPnoitcnuF
1M
2M
3M
(Hydraulic 2-Position Control)
erusserpmetsyS
"A"troP
erusserpmetsyS
"B"troP
erusserPegrahC
System Pressure
Gauge Port M2
Control Pressure
Port X1
System Pressure Port B
eziSeguaG
dna
gnittiF
gnir-O81-61/9
gnir-O81-61/9
gnir-O81-61/9
isp00001rorab0001
isp00001rorab0001
isp0001rorab05
E362200T
Left Side View
troPnoitcnuF
4M
5M
1L
2L
Displacement Control
Cylinder Pressure
Gauge Port M4
Min. Displacement
Displacement Control
Cylinder Pressure
Gauge Port M5
Max. Displacement
(Earlier Production Not available as gauge
port with servo orifices)
Displacement Control
Cylinder Pressure
Gauge Port M5
Max. Displacement
(Newer Production)
eziSeguaG
dna
gnittiF
redbnilyClortnoC
muminiM"erusserP
"tnemecalpsiD
redbnilyClortnoC
mumixaM"erusserP
"tnemecalpsiD
erusserPesaC
isp00001rorab0001
gnir-O02-61/7
isp00001rorab0001
gnir-O02-61/7
isp005rorab01
gnir-O21-61/1-1
E462200T
24
MV with Cartridge Flange and Hydraulic 2-Position Control (SAE Flange Version Similar)
Case Drain Port L1
Case Drain Port L2
Right Side View
MV with SAE Flange (Cartridge Flange Version Similar)
System Pressure
Gauge Port M1
charge Pressure
Gauge Port M3
(Same position as in MF)
Speed Sensor
System Pressure Port A
90000823E
Series 90 Initial Start-Up Procedure
Initial Start-Up Procedure
The following start-up procedure should always be followed when starting-up a new Series 90 installation or
when restarting an installation in which either the pump or
motor had been removed.
WARNING
The following procedure may require the vehicle/
machine to be disabled (wheels raised off the ground,
work function disconnected, etc.) while performing
the procedure in order to prevent injury to the
technician and bystanders. Take necessary safety
precautions before moving the vehicle/machine.
S000 007E
Prior to installing the pump and/or motor, inspect the units
for damage incurred during shipping and handling. Make
certain all system components (reservoir, hoses, valves,
fittings, heat exchanger, etc.) are clean prior to filling with
fluid.
Fill the reservoir with recommended hydraulic fluid. This
fluid should be passed through a 10 micron (nominal, no
bypass) filter prior to entering the reservoir. The use of
contaminated fluid will cause damage to the components,
which may result in unexpected vehicle/machine movement. See the publications BLN-9887 and SDF 697581
for further related information.
The inlet line leading from the reservoir to the pump must
be filled prior to start-up. Check inlet line for properly
tightened fittings and make sure it is free of restrictions
and air leaks.
Be certain to fill the pump and/or motor housing with
clean hydraulic fluid prior to start up.
Fill the housing by pouring filtered oil into the upper case
drain port.
Install a 50 bar (or 1000 psi) pressure gauge in the charge
pressure gauge port to monitor the charge pressure
during start-up.
It is recommended that the external control input signal
(linkage for MDC, hydraulic lines for HDC, or electrical
connections for EDC) be disconnected at the pump
control until after initial start-up. This will ensure that the
pump remains in its neutral position.
WARNING
Do not start prime mover unless pump is in neutral
position (0° swashplate angle). Take precautions to
prevent machine movement in case pump is actuated
during initial start up.
S000 008E
“Jog” or slowly rotate prime mover until charge pressure
starts to rise. Start the prime mover and run at the lowest
possible RPM until charge pressure has been established. Excess air may be bled from the high pressure
lines through the high pressure system gauge port.
Once charge pressure has been established, increase
speed to normal operating RPM. Charge pressure should
be as indicated in the pump model code. If charge
pressure is inadequate, shut down and determine cause
for improper pressure. Refer to Troubleshooting.
WARNING
Take necessary precautions that the motor shaft
remains stationary during the adjustment
procedure.
S000 010E
Shut down the prime mover and connect the external
control input signal. Also reconnect the machine function
if disconnected earlier. Start the prime mover, checking
to be certain the pump remains in neutral. With the prime
mover at normal operating speed, slowly check for forward and reverse machine operation.
Charge pressure may slightly decrease during forward or
reverse operation. Continue to cycle slowly between
forward and reverse for at least five minutes.
Shut down prime mover, remove gauges, and plug ports.
Check reservoir level and add filtered fluid if needed.
The transmission is now ready for operation.
25
Series 90 Fluid and Filter Maintenance
Fluid and Filter Maintenance
To ensure optimum service life of Series 90 products,
regular maintenance of the fluid and filter must be performed. Contaminated fluid is the main cause of unit
ManoVacuummeter
failure. Care should be taken to maintain fluid cleanliness
while performing any service procedure.
to low
pressure
side and
control
Suction Filtration Schematic
Hydraulic fluid reservoir
to low
pressure
side and
control
Hydraulic fluid reservoir
Adjustable
Charge pressure relief valve
To pump case
Screen
Charge pump
Charge pump
Filter
P000 797E
Adjustable
Charge pressure
relief valve
To pump case
Check the reservoir daily for proper fluid level, the presence of water (noted by a cloudy to milky appearance, or
free water in bottom of reservoir), and rancid fluid odor
(indicating excessive heat). If either of these conditions
occur, change the fluid and filter immediately.
It is recommended that the fluid and filter be changed
per the vehicle/machine manufacturer’s recommendations or at the following intervals:
First change
500 operating hours after start up
second and subsequent changes
every 2000 operating hours or once a year.
This recommendation applies for the most applications.
High temperatures and pressures will result in accelerated fluid aging and an earlier fluid change may be
required. At lower fluid loads longer change intervalls are
possible. Therefore we suggest to check the fluid with the
manufacturer for suitability. This should be done at latest
half way between fluid changes.
It may be necessary to change the fluid more frequently
than the above intervals if the fluid becomes contaminated with foreign matter (dirt, water, grease, etc.) or if
the fluid has been subjected to temperature levels greater
than the recommended maximum. Never reuse fluid.
The filter should be changed whenever the fluid is changed
or whenever the filter indicator shows that it is necessary
to change the filter.
26
Filter
Charge Pressure Filtration Schematic
(Partial flow)
P000 798E
level
dednemmoceR β
x
dednemmoceR β
x
noitartlif
noitartliferusserp
ssenilnaelcdiulfderiuqeR
oitar-
noitartlifnoitcusrof
oitar-
erusserpegrahcrof
telnidednemmoceR
egrahcrofezisneercs
dnaleveLssenilnaelC βββββ
β
β
001 µ 521-m µm
oitaR-
x
(57= β01≥ )2
54-53
(57= β01≥ )01
02-51
31/81ssalC6044OSI
E700200T
Series 90 Toubleshooting
Troubleshooting
This section provides general steps to follow if certain undesirable system conditions are observed. Follow the steps in
a section until the problem is solved. Some of the items will be system specific. For areas covered in this manual, a section
is referenced. Always observe the safety precautions listed in the section "Introduction" and related to your
specific equipment.
"NEUTRAL" Difficult or Impossible to Find
Check Description Action
1. Input to pump control.
2. Pump displacement control.
contact a SAUER-SUNDSTRAND Authorized Service Center.
System Operating Hot
Check Description Action
1. Oil level in reservoir.
2. Heat exchanger.
3. Charge pressure.
4. Charge pump inlet vacuum.
Input to control module is operating
improperly.
Control linkages are not secure, control
orifices are blocked, etc.
If the above actions do not remedy the problem
Insufficient hydraulic fluid will not meet
cooling demands of system.
Heat exchanger not sufficiently cooling
the system.
Low charge pressure will overwork system.
High inlet vacuum will overwork system. A dirty filter will increase the inlet
vacuum. Inadequate line size will restrict flow.
Check control input and repair or replace as necessary.
Adjust, repair, or replace control module as necessary.
Fill reservoir to proper level.
Check air flow and input air temperature for heat exchanger. Clean, repair
or replace heat exchanger.
Measure charge pressure. Inspect and
adjust or replace charge relief valve. Or
repair leaky charge pump.
Check charge inlet vacuum. If high,
inspect inlet filter and replace as necessary. Check for adequate line size,
length or other restrictions.
5. System relief pressure settings.
6. For internal leakage in motor.
7. System pressure.
contact a SAUER-SUNDSTRAND Authorized Service Center.
If the system relief settings are too low,
the relief valves will be overworked.
Leakage will reduce low side system
pressure and overwork the system.
High system pressure will overheat
system.
If the above actions do not remedy the problem
Verify settings of pressure limiters and
high pressure relief valves and adjust
or replace multi-function valves as necessary.
Monitor motor case flow without loop
flushing in the circuit (use defeat spool).
If flow is excessive, replace motor.
Measure system pressure. If pressure
is high reduce loads.
27
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