EZT
®
Integrated Zero-Turn Transaxle
Service and Repair Manual
(ZC & ZD Models)
BLN-52622
July 2010
TABLE OF CONTENTS
Section Page
Foreword .............................................................................................................................. 1
Description and Operation ................................................................................................. 2
Introduction .................................................................................................................................................. 2
General Description ..................................................................................................................................... 2
Hydraulic Schematic .................................................................................................................................... 3
External Features -EZT® ......................................................................................................................... 4
Technical Specications ............................................................................................................................... 5
Product Identication ................................................................................................................................... 5
Safety .................................................................................................................................... 6
Personal Safety ............................................................................................................................................ 6
Tool Safety ................................................................................................................................................... 6
Work Area Safety ......................................................................................................................................... 6
Servicing Safety ........................................................................................................................................... 6
Troubleshooting .................................................................................................................. 7
Service and Maintenance.................................................................................................... 8
External Maintenance .................................................................................................................................. 8
Service and Maintenance Procedures ......................................................................................................... 8
Fluids ........................................................................................................................................................... 8
Fluid Volume and Level ................................................................................................................................ 8
Fluid Change Procedure .............................................................................................................................. 9
Purging Procedures ................................................................................................................................... 10
Return to Neutral Setting ............................................................................................................................11
Repair ................................................................................................................................. 12
How To Use This Section ........................................................................................................................... 12
General Instructions ................................................................................................................................... 12
Transaxle Removal .................................................................................................................................... 12
Limited Disassembly .................................................................................................................................. 12
Tools and Torques ...................................................................................................................................... 13
Hub Replacement ................................................................................................................................. 14-15
Control Arm and Bypass Arm ..................................................................................................................... 16
Seal Kit Replacement ................................................................................................................................ 17
Cog Brake Assembly .................................................................................................................................. 18
Disc Brake Assembly ................................................................................................................................. 19
Side Cover ................................................................................................................................................ 20
Axle Shaft, Reduction Gears and Expansion Plate .................................................................................... 21
Motor Shaft ................................................................................................................................................ 22
Input Shaft and Bypass Rod ...................................................................................................................... 23
Hydraulic Components .......................................................................................................................... 24-28
Transaxle Installation ................................................................................................................................. 28
Assembly After a Complete Teardown ....................................................................................................... 29
Sealant Application ........................................................................................................... 30
Parts List ...................................................................................................................... 32, 33
Glossary of Terms ....................................................................................................... 34, 35
FOREWORD
Headquartered in Sullivan, Illinois, Hydro-Gear®
is a world leader in the design, manufacture,
and service of quality hydrostatic transaxles for
the lawn and garden industry. The mission of
our company is to be recognized by our customers and the industry as a world-class supplier
and the quality leader in everything we do.
This Service and Repair Manual is designed
to provide information useful in servicing and
troubleshooting the Hydro-Gear EZT
®
Inte-
grated Zero-Turn Transaxle.
Also included is a glossary of terms that are
frequently used throughout the industry and in
Hydro-Gear service publications. Understanding terminology is very important!
It is necessary, and a good shop practice, that
your service area be equipped with the proper
tools and the mechanics be supplied the latest
information available. All repair procedures
illustrated in this guide are suggested, but preferred methods of repair.
Repair procedures require that the transaxle
unit be removed from the vehicle.
This is not a certication, test or study guide for
a certication test. If a technician is interested
in certication, they should contact an agent
representing OPEESA (Outdoor Power Equipment and Engine Service Association) at (860)
767-1770 or their Hydro-Gear Central Service
Distributor. Many distributors will be hosting
certication testing. These study guides will
cover most of the products and manufacturers
in our industry.
For more information about Hydro-Gear or our
products, please contact your Central Service
Distributor, or call our Customer Service Department at (217) 728-2581.
®
1
EZT
SECTION 1. DESCRIPTION AND OPERATION
INTRODUCTION
The purpose of this manual is to provide information useful in servicing the Hydro-Gear
®
Integrated Zero-Turn Transaxle (EZT®). This manual includes the EZT’s general descriptions,
hydraulic schematics, technical specications,
servicing and troubleshooting procedures.
The transaxle normally will not require servicing during the life of the vehicle in which it is
installed. Should other servicing be required,
the exterior of the transaxle will need to be
thoroughly cleaned before beginning most
procedures. Do not wash the transaxle while
it is hot. Do not use a pressure washer to
clean the unit.
GENERAL DESCRIPTION
The EZT is a self contained unit designed for
the transfer and control of power. It provides an
innitely variable speed range between zero
and maximum in both forward and reverse
modes of operation.
This transaxle uses a variable displacement
pump with a maximum displacement of 10cc
per revolution, and motor with a fixed displacement of 10cc per revolution. The variable displacement pump features a trunnion
mounted swashplate with a direct-proportional
displacement control. Reversing the direction
of the swashplate reverses the ow of oil from
the pump and thus reverses the direction of the
motor output rotation. The pump and motor are
of the axial piston design and utilize spherical
nosed pistons which are held against a thrust
race by internal compression springs.
The EZT has a self contained uid supply and
an internal lter. The uid is forced through
the lter by a positive “head” on the uid in the
housing/expansion tank with an assist by the
negative pressure created in the pump pistons
as they operate.
The check valves in the center section are used
to control the make-up ow of the uid to the
low pressure side of the loop.
A cam style, block lifting bypass is utilized in
the EZT to permit moving the vehicle for a short
distance at a maximum of 2 m.p.h. (3.2 Km/h)
without starting the engine.
WARNING
Actuating the bypass will result in the
loss of hydrostatic braking capacity. The
machine must be stationary on a level
surface and in neutral when actuating
the bypass.
Figure 1. Hydraulic Schematic
2 EZT
®
EZT® HYDRAULIC FLOW SCHEMATIC
Figure 2. Hydraulic Flow Illustration
HYDRAULIC SCHEMATIC
Figure 2 provides an illustration of the hydraulic
oil circuit. The oil supply for the hydraulic system of the EZT® is also utilized for lubricating
the components of the nal drive assembly.
The input shaft and pump cylinder block are
turned in one direction only by the engine/
drive belt/pulley combination. Output of the oil
ow is controlled by the direction and amount
that the variable swashplate is angled. As the
pump pistons compress they force the oil to
ow through one of two passageways (forward
or reverse) in the center section to the motor
cylinder block and motor shaft. Since the mo-
tor has a xed displacement angle it is forced
to turn with the ow of oil. As the angle of the
pump swashplate is increased the amount of
oil being pumped will increase and cause a
higher speed output of the motor. Reversing
the angle of the pump swashplate will reverse
the direction of oil ow.
During the operation of the transaxle, uid
is “lost” from the hydraulic loop through leak
paths designed into the product for lubrication
purposes (around pistons, under the rotating
cylinder blocks, etc.). This “lost” uid returns
to the transaxle housing, then is pulled back
into one of the check valves depending upon
the direction of vehicle operation. All of this oil
must pass through an internal lter.
The motor cylinder block mounts onto a splined
motor shaft which drives the gear train.
The bypass feature in the EZT has a mechanical
lever which lifts the motor block off of the center
section running surface. This allows oil ow
from the cylinder blocks to be discharged.
®
3
EZT
EXTERNAL FEATURES EZT
MAIN HOUSING
®
AXLE SHAFT
BYPASS ARM
SIDE COVER
FILL PORT
BRAKE ARM
INPUT SHAFT
CONTROL ARM
COG BRAKE DISC
FAN
PULLEY
AXLE SHAFT
4 EZT
®
TECHNICAL SPECIFICATIONS
Technical specications for the EZT® are listed in Table 1.
Table 1. Technical Specications
Input Speeds Weight of Unit
Maximum: 3000 RPM 29 lbs. (13 Kg)
Minimum: 1800 RPM
Table 2. EZT Component Options
Component Component Options
Axle Shaft Diameter and End Options: 1˝ Flange 1˝ DD
Brake Location: Inboard Outboard
Brake Type: Cog Disc
Control Arm Location: Inboard Outboard
Control Arrangements: Standard Control Arm RTN (scissor style)
Overall Transaxle Reduction: 19.2:1 21.2:1
PRODUCT IDENTIFICATION
The model and conguration of the EZT can be determined from the label shown in Figure 3.
Figure 3. Conguration Label
®
5
EZT
SECTION 2. SAFETY
This symbol points out important safety
instructions which, if not followed, could endanger the personal safety and/or property of yourself and others. Read and follow all instructions in this manual before attempting maintenance on your transaxle. When you see this
symbol - HEED ITS WARNING.
WARNING
POTENTIAL FOR SERIOUS INJURY
Inattention to proper safety, operation,
or maintenance procedures could result
in personal injury, or damage to the
equipment. Before servicing or repairing the EZT
the safety precautions described in this
section.
®
, fully read and understand
PERSONAL SAFETY
Certain safety precautions must be observed
while servicing or repairing the EZT. This section addresses some of these precautions but
must not be considered an all-inclusive source
on safety information. This section is to be
used in conjunction with all other safety material
which may apply, such as:
1) Other manuals pertaining to this machine,
2) Local and shop safety rules and codes,
3) Governmental safety laws and regulations.
Be sure that you know and understand the
equipment and the hazards associated with it.
Do not place speed above safety.
Notify your supervisor whenever you feel there
is any hazard involving the equipment or the
performance of your job.
Never allow untrained or unauthorized personnel to service or repair the equipment.
Wear appropriate clothing. Loose or hanging
clothing or jewelry can be hazardous. Use the
appropriate safety equipment, such as eye
and hearing protection, and safety-toe and
slip-proof shoes.
Never use compressed air to clean debris from
yourself or your clothing.
TOOL SAFETY
Use the proper tools and equipment for the
task.
Inspect each tool before use and replace any
tool that may be damaged or defective.
WORK AREA SAFETY
Keep the work area neat and orderly. Be sure
it is well lit, that extra tools are put away, trash
and refuse are in the proper containers, and dirt
or debris have been removed from the working
areas of the machine.
The oor should be clean and dry, and all extension cords or similar trip hazards should be
removed.
SERVICING SAFETY
Certain procedures may require the vehicle to
be disabled in order to prevent possible injury
to the servicing technician and/or bystanders.
The loss of hydrostatic drive line power may
result in the loss of hydrostatic braking capability.
Some cleaning solvents are ammable. Use
only approved cleaning materials: Do not use
explosive or ammable liquids to clean the
equipment.
To avoid possible re, do not use cleaning
solvents in an area where a source of ignition
may be present.
Discard used cleaning material in the appropriate containers.
6 EZT
®
SECTION 3. TROUBLESHOOTING
WARNING
Do not attempt any servicing or adjustments with the engine running.
Use extreme caution while inspecting
the drive belt assembly and all vehicle
linkage!
related to a defective transaxle, but are caused
by slipping drive belts, partially engaged bypass
valves, and loose or damaged control linkages.
Be sure to perform all operational checks and
adjustments outlined in Section 4, Service
and Maintenance, before assuming the pump
is malfunctioning. Table 3 below provides a
In many cases, problems with the EZT® are not
Follow all safety procedures outlined in
the vehicle owner’s manual.
Table 3. EZT Troubleshooting Checklist
troubleshooting checklist to help determine the
cause of operational problems.
Possible Cause Corrective Action
UNIT OPERATES IN ONE DIRECTION ONLY
Control linkage bent or out of adjustment Repair or replace linkage, Page 8
Drive belt slipping or pulley damaged Repair or replace drive belt or pulley, Page 8
VEHICLE DOES NOT DRIVE/TRACK STRAIGHT
Vehicle tires improperly inated Refer to vehicle manufacturer suggested pressure
Control linkage bent or out of adjustment Repair or replace linkage, Pages 8 and 11
Bypass assembly sticking Repair or replace bypass, Page 21
UNIT IS NOISY
Oil level low or contaminated oil Fill to proper level or change oil, Page 9
Excessive loading Reduce vehicle loading, Page 8
Loose parts Repair or replace loose parts
Bypass assembly sticking Repair or replace linkage
Air trapped in hydraulic system Purge hydraulic system, Page 10
UNIT HAS NO/LOW POWER
Engine speed low Adjust to correct setting
Control linkage bent or out of adjustment Repair or replace linkage, Page 8
Drive belt slipping or pulley damaged Repair or replace drive belt or pulley, Page 8
Oil level low or contaminated oil Fill to proper level or change oil, Page 9
Excessive loading Reduce vehicle loading, Page 8
Bypass assembly sticking Repair or replace linkage
Air trapped in hydraulic system Purge hydraulic system, Page 10
UNIT IS OPERATING HOT
Debris buildup around transaxle
Cooling fan damaged Repair or replace cooling fan
Oil level low or contaminated oil Fill to proper level or change oil, Page 9
Excessive loading Reduce vehicle loading, Page 8
Air trapped in hydraulic system Purge hydraulic system, Page 10
Clean off debris, Pages 2 and 8
TRANSAXLE LEAKS OIL
Damaged seals, housing, or gaskets Replace damaged component
Air trapped in hydraulic system Purge hydraulic system, Page 10
®
7
EZT
SECTION 4. SERVICE AND MAINTENANCE
NOTE: Any servicing dealer attempting
a warranty repair must have prior approval before conducting maintenance
of a Hydro-Gear® product unless the
servicing dealer is a current Authorized
Hydro-Gear Service Center.
EXTERNAL MAINTENANCE
Regular external maintenance of the EZT®
should include the following:
1. Check the vehicle operator’s manual for
the recommended load ratings. Insure
that the current application does not
exceed load rating.
2. Check oil level in accordance with Figure 4
Page 9.
3. Inspect the vehicle drive belt, idler pulley(s),
and idler spring(s). Insure that no belt slippage can occur. Slippage can cause low
input speed to the transmission.
4. Inspect the vehicle control linkage to the
directional control arm on the transaxle. Also
insure that the control arm is securely fastened to the trunnion arm of the transaxle.
FLUIDS
The uids used in Hydro-Gear products have
been carefully selected, and only equivalent, or
better products should be substituted.
Typically, an engine oil with a minimum rating
of 9.0 cSt (55 SUS) at 230° F (110° C) and an
API classication of SL is recommended. A
20W50 engine oil has been selected for use
by the factory and is recommended for normal
operating procedures.
FLUID VOLUME AND LEVEL
Fluid volume information is provided in Table
4.
Certain situations may require additional uid
to be added or even replaced. Refer to Page 4
for the proper ll port location.
Fill the EZT so the oil level is .75”-1.50” (19-38
mm) below the oil ll port.
Recheck the uid level once the unit has been
operated for approximately 1 minute.
Purging will be required. Refer to the purging
procedures on Page 10.
5. Inspect the bypass mechanism on the transaxle and the vehicle linkage to insure that
both actuate and release fully.
SERVICE AND MAINTENANCE
PROCEDURES
Some of the service procedures presented on
the following pages can be performed while
the EZT is mounted on the vehicle. Any repair
procedures as mentioned in the repair section
of this manual must be performed after the
unit has been removed from the vehicle. The
unit should be thoroughly cleaned before any
service procedures are performed.
8 EZT
®
FLUID CHANGE
FLUID CHANGE PROCEDURE
This transaxle is factory lled, sealed and does
not require oil maintenance. However, in the
event of oil contamination or degradation, oil
addition or change may alleviate certain performance problems.
1. Remove the transaxle from the vehicle.
NOTE: If removing the wheel from the
transaxle, do so by removing the four (4)
lug nuts. Do not remove the axle/hub nut.
2. Clean the oil ll port area of any debris.
3. Remove the oil ll port tting.
Table 4. Fluid Volumes for the EZT
Fluid Description
4. Position the transaxle so the oil will drain
completely out of the housing.
5. Fill the transaxle at the oil ll port according
to Figure 4.
6. Install the oil ll port tting.
7. Purging will be required. Refer to the purging
procedures on Page 10.
8. Recheck the uid level once the unit has
been operated for approximately 1 minute.
®
Volume
20W50 engine oil
OIL LEVEL
52.4 . oz. (1550 ml) to 55.8 . oz. (1650 ml)
TOP OF FILL PORT
0.75” - 1.50” (19-38mm) depth
at 50°-100°F (10°-38°C)
Figure 4. Fluid Level and Fill Port
®
9
EZT
PURGING PROCEDURES
Due to the effects air has on efciency in hydrostatic drive applications, it is critical that it is
purged from the system.
These purge procedures should be implemented any time a hydrostatic system has
been opened to facilitate maintenance or any
additional oil has been added to the system.
Air creates inefciency because its compression and expansion rate is higher than that of
the oil approved for use in hydrostatic drive
systems.
The resulting symptoms in hydrostatic systems
may be:
1. Noisy operation.
2. Lack of power or drive after short term operation.
3. High operation temperature and excessive
expansion of oil.
Before starting, make sure the transaxle/trans-
mission is at the proper oil level. If it is not, ll
to the specications outlined on Page 9, Figure
4.
The following procedures should be performed
with the vehicle drive wheels off the ground,
then repeated under normal operating conditions.
1. With the bypass valve open and the engine
running, slowly move the directional control
in both forward and reverse directions (5 or
6 times), as air is purged from the unit, the
oil level will drop.
2. With the bypass valve closed and the engine
running, slowly move the directional control
in both forward and reverse directions (5 to
6 times). Check the oil level, and add oil as
required after stopping the engine.
3. It may be necessary to repeat Steps 1 and
2 until all the air is completely purged from
the system. When the transaxle moves forward and reverse at normal speed purging
is complete.
10 EZT
®
RETURN TO NEUTRAL SETTING
WARNING
POTENTIAL FOR SERIOUS INJURY
Inattention to proper safety, operation,
or maintenance procedures could result
in personal injury, or damage to the
equipment. Before servicing or repairing the EZT®, fully read and understand
the safety precautions described in this
section.
The return to neutral mechanism on the transmission is designed to set the directional control into a neutral position when the operator
releases the vehicle hand control. Follow the
procedures below to properly adjust the return
to neutral mechanism on the transaxle:
1. Conrm the transaxle is in the operating
mode (bypass disengaged). Raise the vehicle’s
drive tires off the ground to allow free rotation.
NOTE: It may be necessary to remove the
drive wheel from the axle hub to access the
linkage control and the transaxle return arm.
Remove the wheel by removing the four (4)
lug nuts. Do not remove the axle/hub nut.
2. Remove the Original Equipment Manufacturer’s (OEM’s) control linkage at the control arm.
Refer to Figure 5.
3. Start the engine and increase the throttle to
AXLE
ROTATION
“B”
AXLE
ROTATION
“A”
WARNING
Do not attempt any servicing or adjustments with the engine running.
Use extreme caution while inspecting
the drive belt assembly and all vehicle
linkage!
Follow all safety procedures outlined in
the vehicle owner’s manual.
full engine speed.
4. Check for axle rotation. If the axle does not
rotate, go to Step 5. If the axle rotates, go to
Step 6.
5. Stop the vehicle’s engine. Reattach and
adjust the OEM linkage according to Step 3
and Step 4. Stop the vehicle engine. Refer
to Figure 5.
6. Note the axle directional movement. Stop
the vehicle engine. Loosen the RTN adjustment screw until the control arm can be rotated.
Rotate the control arm in the opposite direction
of the wheel rotation in 5 degree increments.
Tighten the RTN adjustment screw. Refer
to table 6. Required Torque values, page 13.
Recheck according to steps 3 and 4. Stop
the vehicle engine. Reattach and adjust the
OEM linkage according to the OEM manual.
Recheck according to steps 3 and 4. Refer to
Figure 5.
AXLE ROTATION “B”AXLE ROTATION “A”
15°
15°
RTN Adjustment Screw
Speed and Directional Control
Figure 5. Return to Neutral Setting
®
11
EZT
SECTION 5. REPAIR
HOW TO USE THIS MANUAL
Each subassembly illustrated in this section is
illustrated with an exploded view showing the
parts involved. The item reference numbers
in each illustration are for assembly instructions only. See page 31 for part names and
descriptions. A complete exploded view and
item list of the transaxle is provided at the end
of the repair section.
GENERAL INSTRUCTIONS
Cleanliness is a primary means of assuring
satisfactory life on repaired units. Thoroughly
clean all exposed surfaces prior to any type
of maintenance. Cleaning of all parts by using a solvent wash and air drying is usually
adequate. As with any precision equipment,
all parts must be kept free of foreign material
and chemicals.
Protect all exposed sealing surfaces and open
cavities from damage and foreign material. The
external surfaces should be cleaned before
beginning any repairs.
Upon removal, it is recommended that all seals,
O-rings, and gaskets be replaced. During
installation lightly lubricate all seals, O-rings
and gaskets with a clean petroleum jelly prior
to assembly. Also protect the inner diameter of
seals by covering the shaft with a cellophane
(plastic wrap, etc.) material.
Parts requiring replacement must be replaced
from the appropriate kits identied in the Items
Listing, found at the end of this manual. Use
only original Hydro-Gear® replacement parts
found in BLN-51427 (CD).
IMPORTANT: When internal repair is performed on the EZT
®
, the lter assembly must
be replaced.
TRANSAXLE REMOVAL
It is necessary to remove the EZT from the vehicle before performing the repair procedures
presented in this section.
NOTE: If removing the wheel from the
transaxle, do so by removing the four (4)
lug nuts. Do not remove the axle/hub nut.
LIMITED DISASSEMBLY
The following procedures are presented in
the order in which they must be performed to
completely disassemble the unit. Do not disassemble the unit any farther than is necessary
to accomplish the required repairs. Each disassembly procedure is followed by a corresponding assembly procedure.
Reassembly is accomplished by performing
the “Assembly” portions of the procedures. If
the unit has been completely disassembled, a
summary of the assembly procedures, in the
order in which they should occur, is given on
page 29.
12 EZT
®
TOOLS AND TORQUES
Table 5. Required Tools
Miscellaneous
EZT® Service & Repair Manual
Flat Blade Screw Driver (2)
Torque Wrench
Air Impact Wrench
Rubber Mallet
Breaker Bar
Side Cutters/Snips
Pliers
Needle Nose
Large External Snap Ring
Small Internal Snap Ring
Table 6. Required Torque Values
Sockets
1/2”-3/8” Adapter
3/8” Deep
1/2” Deep
7/16” Deep
9/16” Deep
3/4” Deep
13/16” Deep
7/8”
T-25 Torx Head
T-40 Torx Head
Apex AN-08
Operation Torque Item Description
Metal Plug 180-240 lb-in [20-27 Nm] 7 Plug 9/16-18
Side Housing Screws 105-155 lb-in [12-17 Nm] 9 Screw 1/4-20 x 1.25
Center Section Bolts 525-700 lb-in [60-80 Nm] 12 Screw 3/8-24 x 2.5
Control Arm Stop Stud 50-120 lb-in [6-18 Nm] 21 Stud 5/16-24
Control Arm Screw 230-310 lb-in [26-35 Nm] 25 Screw 5/16-24 x 1
Stop Stud Nut 85-120 lb-in [10-14 Nm] 26 Nut, Lock 5/16-24 UNF
Check Plugs 280-400 lb-in [32-45 Nm] 56 Check Plug Assembly
Expansion Plate Screws 25-50 lb-in [3-6 Nm] 65 Screw 10-32 x 0.50
Brake Assembly Screw 80-120 lb-in [9-14 Nm] 73 Screw 1/4-20 x 1
Hub Locknut 240-260 lb-ft [271-298 Nm] 99 Nut, Hex 3/4-16 Lock
Fan/Pulley Lock Nut 360-520 lb-in [41-59 Nm] 122 Lock Nut 1/2 x 20
Breather Fitting 180-240 lb-in [20-27 Nm] 126 Fitting 9/16
RTN Adjustment Screw 175-200 lb-in [19-22 Nm] 131 Screw 5/16-24 x 1
Disc Brake Screw 80-120 lb-in [9-14 Nm] 157 Screw 1/4-20 x 2
®
13
EZT
WHEEL HUB AND NUT (CODE - A, C, F, or H)
124
99
Character 4 in the model number code = A, C, F, or H
EXAMPLE: Z H
Refer to Figure 6.
- -
*
*
**
**** ****
-
Disassembly
NOTE: This procedure is only necessary if
your unit is equipped with a pin locking
nut (Figure 6a). Other units under this
code are not equipped with a pin locking nut.
1. Place the axle so that the pin lock is at the
9 o’clock position.
2. Place a punch on the pin lock of the nut
(99).
3. Tap on the end of the punch with a rubber
mallet until the pin lock moves off of the
shaft.
4. Remove and discard the pin locking nut.
Assembly
NOTE: Anytime a hub and/or hub nut is
removed, it must be replaced with a new
hub and/or hub nut.
1. Install hub (124) onto the shaft.
2. Install nut (99) onto shaft. Torque according
to specications in Table 6 on page 13.
5. Remove the hub (124).
Inspection
1. Inspect the hub and axle splines for any
damage.
Figure 6a. Pin locking nut.
Punch
Pin Lock
Figure 6b. Pin locking nut removal.
14 EZT
®
WHEEL HUB AND NUT (CODE - P, R, T, or U)
Character 4 in the model number code = P, R, T, or U
EXAMPLE: Z P
- -
* *
Refer to Figure 7.
**** ****
**
-
Disassembly
NOTE: The following procedure is used
for teardown of the EZT unit when assembled with a taper lock shaft. The
hub and hub nut should not be removed
unless they have been damaged.
1. Reference page 18 and 19 for side housing
brake assembly removal.
2. Remove the side housing screws (9).
3. Remove side housing (68).
4. Remove axle retaining ring (45).
5. Remove bull gear (46).
6. Slide axle shaft and hub assembly out of
main housing in the direction of the arrow
(Figure 7).
Assembly
NOTE: In a situation that a hub and/or
hub nut is damaged and must be removed it must be replaced with a new
hub and/or hub nut.
1. Slide axle shaft assembly into axle horn of
main housing (66).
NOTE: Cover the end of the axle shaft
with cellophane to protect the seal during installation of the axle shaft assembly.
2. Install bull gear (46) and axle retaining ring
(45).
3. Install side housing (66) and side housing
screws (9). Refer to Table 6 for screw torque
specications.
Inspection
1. Inspect the components for damage.
46
45
68
Axle and Hub Assembly
66
16X 9
®
15
EZT
Figure 7. Taper Lock Shaft/Hub Design Removal.
CONTROL ARM AND BYPASS ARM
Refer to Figure 8.
Disassembly
1. Loosen and remove the lock nut (26) and
at washer (24). Discard the lock nut (26)
and at washer (24).
2. Remove the torx head screw (25) from the
directional control.
3. Remove control arm (23) and pucks (22).
Discard the pucks.
4. Remove the bypass arm retaining ring (18)
and bypass arm (17). Discard the retaining
ring.
5. If necessary, remove and replace the control
arm stop stud (21).
Inspection
1. Inspect the control arm stop stud (21) for
wear or damage.
Assembly
1. Install the bypass arm (17) onto the bypass
rod. Secure the bypass arm with a new retaining ring (18).
2. Replace the control arm stop stud (21) if
removed. Torque according to specications
in Table 6 on page 13.
3. Install the control arm (23).
4. Install the control arm screw (25). Refer to
Table 6 for screw torque specications.
2. Inspect the control arm (23) for wear or
damage.
3. Inspect the bypass arm (17) for wear or
damage.
Figure 8. Control Arm and Bypass Arm
16 EZT
®
SEAL KIT REPLACEMENT
Before disassembly, wipe the unit free of any
debris to avoid contamination.
Refer to Figure 9.
Input Seal
1. Remove the input pulley from the input
shaft.
2. Remove the seal retaining ring (34).
3. Carefully pull the input seal (33) out of the
housing bore with a “hook” type tool. Care
must be taken to avoid damage to the housing bore or shaft sealing area.
4. Lubricate the new seal with petroleum jelly
prior to installation.
5. Wrap the shaft keyway (splines) with cellophane to prevent damage to the seal lip
during installation.
Trunnion Seal
1. Remove the control arm and any attachments to the control arm. See page 16.
2. The seal (20) can be replaced by following
steps 3-6 of the procedure used to replace
the input shaft.
Bypass Seal
1. Remove the bypass arm and any attachments to the bypass arm. See page 16.
2. Remove the seal retaining ring (16). Remove the bypass rod, keeping the retaining
ring (14) attached. Remove the bypass rod
seal (13). Deburr the bypass rod.
3. Install the seal (13). Install the bypass rod
with the retaining ring (14) attached. Install
the seal retaining ring (16).
6. Slide the seal over the shaft and press it into
the housing bore.
7. The seal should seat against the spacer.
8. Install the seal retaining ring (34) and make
sure it is fully seated in its groove.
Output Seal
1. The seal (51) can be replaced by following
steps 2-6 of the procedure used to replace
the input seal.
2. Install the retaining ring (34) and make sure
it is fully seated in its groove.
Motor Shaft Seal
1. Remove the brake assembly. See pages
18-19.
2. The seal (10) can be replaced by following
steps 3-6 of the procedure used to replace
the input shaft.
Figure 9. Seal Kit Replacement
®
17
EZT
COG BRAKE ASSEMBLY
Refer to Figure 10.
Disassembly
1. Remove the control arm and bypass arm.
See page 16.
2. Remove the oil from the transaxle. See page
9.
3. Remove the brake arm spring (75), if installed. Remove the brake arm screw(s)
(73), washer(s) (72), brake arm (74) and
bushing(s) (71).
4. Remove the retaining ring (14) and cog
brake disc (100).
5. Remove the motor shaft lip seal (10), if removing the side housing.
Inspection
1. Check the brake arm and cog brake disc for
excessive wear or teeth damage. Replace
if necessary.
2. Check for excessive looseness at the arm
pivot point.
Assembly
1. Install the motor shaft lip seal (10), if removed. Refer to page 16. Remember to use
a seal protector during installation.
2. Install the cog brake disc (100) and retaining
ring (14).
3. Install the bushing(s) (71), brake arm (74),
washer(s) (72) and brake arm screw(s) (73).
Torque screws to 80-120 in-lbs (9-14 Nm).
4. Install the brake arm spring (75), if removed.
5. Fill the transaxle with new oil. See page 9.
6. Install the bypass arm and control arm. See
page 16.
100
14
74
71
75
72
73
18 EZT
72
73
Figure 10. Cog Brake Assembly
10
71
®
DISC BRAKE ASSEMBLY
Refer to Figure 11.
Disassembly
1. Remove the control arm and bypass arm.
See page 16.
2. Remove the oil from the transaxle. See page
9.
3. Remove the brake arm bias spring (75).
4. Remove the cotter pin (160), castle nut (159)
and washer (158).
5. Remove the brake arm (74), compression
spring (156) and two brake pins (155).
6. Remove the brake yoke assy screws (73
& 157), the spacer (154), brake yoke assy
(153), puck plate (151), outer puck (150),
rotor (100) and inner puck (150).
7. Remove the motor shaft lip seal (10), if removing the side housing.
Inspection
2. Check for excessive looseness at the arm
pivot point.
Assembly
1. Install the motor shaft lip seal (10), if removed. Refer to page 17. Remember to use
a seal protector during installation.
2. Install the inner puck (150), rotor (100), outer
puck (150) and puck plate (151).
3. Install the brake yoke assy (153), brake pins
(155), spacer (154) and the brake yoke assy
screws (73 & 157).
4. Install the compression spring (156), the
brake arm (74), the washer (158), the castle
nut (159) and the cotter pin (160).
5. Install the brake arm bias spring (75).
7. Fill the transaxle with new oil. See page 9.
8. Install the bypass arm and control arm. See
page 16.
1. Check the brake disc and pucks for excessive wear. Replace if necessary.
100
157
153
154
75
74
160
158
2X 155
156
159
10
151
2X 150
153
73
Figure 11. Disc Brake Assembly
®
19
EZT
SIDE COVER
Refer to gure 12.
Disassembly
1. Remove the control arm and bypass arm.
See page 16.
2. Remove the oil from the transaxle. See page
9.
3. Remove the brake assembly. See pages 18
and 19.
4. Remove the motor shaft lip seal. See page
17.
5. Remove the side housing screws (9) and
belt deector (144), if installed.
6. Pull the side housing (68), leaving the axle
(49) and bull gear (46) assembled in the
main housing. It may be necessary to use
pry tools at the pry points to break loose
the sealant (positions 1-16 and 4-6, Figure
12).
Inspection
1. Inspect the bearing and bushing areas of
the side cover.
Assembly
1. Apply a bead of sealant around the perimeter of the side housing face. See sealant
pattern on page 30.
2. Install the locating pins (8), if not already
installed.
3. Install the side housing (2). Use care not to
smear the sealant bead.
4. Install the side housing screws (9) and belt
deector (144, if used). Refer to the screw
tightening pattern in Figure 12 and torque
specication in Table 6 on page 13.
5. Install the remaining seals. Refer to page
17. Remember to use a seal protector during installation.
7. Clean off all the old sealant on the side and
main housings. Take care not to damage the
sealing surfaces. A wire brush and solvent
is effective.
66
2X 8
16X 9
68
144
6. Install the brake assembly. See pages 18
and 19.
7. Fill the transaxle with new oil. See page 9.
8. Install the bypass arm and control arm. See
page 16.
14
16
1
3
5
12
9
7
10
8
11
13
6
4
2
15
Figure 12. Side Cover
20 EZT
®
AXLE SHAFT, REDUCTION GEARS AND EXPANSION PLATE
Refer to Figure 13.
Disassembly
1. Remove the bypass arm and control arm.
See page 16.
2. Remove oil from the transaxle. See page
9.
3. Remove the side cover. See page 20.
4. Remove the spiral retaining ring (45), bull
gear (46), inboard sleeve bearing (48) and
washer (47).
5. Remove the reduction gears (42 &43), jack
shaft pin (44) and washers (41).
6. Remove seal retaining ring (34), seal (51),
axle (49) and bushing (50).
7. If necessary, remove the expansion plate
assembly (53).
NOTE: Expansion plate removal will typically
destroy the plate. Clean all sealant from the
expansion plate area.
Inspection
1. Inspect the bull gear for wear or damage.
2. Inspect the reduction gears, jack shaft pin
and washers.
3. Inspect the axle shaft, bearing and bushing.
4. Inspect the expansion plate.
Assembly
1. Apply a small bead of sealant to the expansion plate area of the housing. See page 29.
Install the expansion plate (53). Torque the
screws according to Table 6.
2. Reassemble and install the reduction gears
(42 & 43), jack shaft pin (44) and washers
(41).
3. Install the bull gear (46), retaining ring (45),
bearing (48) and washer (47) onto the axle
(49).
4. Install the axle (49) and bushing (50) into
the housing (1).
5. Install the axle seal (51) and retaining ring
(34).
6. Install the side cover. See page 20.
7. Install all remaining seals. See page 17.
8. Fill the transaxle with oil. See page 9.
9. Install the bypass arm and control arm. See
page 16.
Figure 13. Axle Shaft, Reduction Gears and Expansion Plate
®
21
EZT
MOTOR SHAFT
Refer to Figure 14.
Disassembly
1. Remove the control arm and bypass arm.
See page 16.
2. Drain the oil from the transaxle. See page
9.
3. Remove the side cover. See page 20.
4. Remove the reduction gears. See page
21.
5. Remove at washer (36), motor shaft and
pinion gear (39 & 38) and at washer (40).
Inspection
1. Inspect the motor shaft (39), pinnion gear
(38) and at washers (36 & 40) for wear or
damage.
Assembly
1. Insert the motor shaft (39) with the pinnion
gear (38) and at washers (36 & 40) into the
center section (57).
2. Install the reduction gears. See page 21.
3. Install the side cover. Refer to page 20.
4. Install new seals. Refer to page 17.
5. Fill the transaxle with oil. See page 9.
6. Install the bypass arm and control arm. See
page 16.
Figure 14. Motor Shaft
22 EZT
®
INPUT SHAFT AND BYPASS ROD
Refer to Figure 15.
Disassembly
1. Remove the control arm and bypass arm.
See page 16.
2. Drain the oil from the transaxle. See page
9.
3. Remove the side cover. See page 20.
4. Remove the reduction gears. See page
21.
5. Remove the motor shaft. See page 22.
6. Remove the retaining ring (34) and shaft
seal (33). Discard the seal.
7. Remove the spacer (32) and input shaft
assembly (29, 30 & 31).
installing the input shaft seal.
5. Deburr the end of the bypass rod. Install the
bypass rod (15), retaining ring (14), seal (13)
and retaining ring (16).
6. Install the motor shaft. See page 22.
7. Install the reduction gears. See page 21.
8. Install the side cover. See page 20.
9. Install new seals in the side housing. See
page 17.
10. Fill the transaxle with oil. See page 9.
11. Install the bypass arm and control arm. See
page 16.
8. Remove the compression spring (27) and
washer (28).
9. Remove the rings (14 & 16), bypass rod (15)
and seal (13).
Inspection
1. Inspect the input shaft components and
bypass rod for wear or damage.
Assembly
1. Visually ensure that the pump block is
aligned concentrically with the center section running face.
2. Install the compression spring (27) and
washer (28).
3. Insert the input shaft (29), with bearing (30)
and retaining ring (31), into the pump block
assembly. NOTE: Do not force the shaft and
bearing as damage may occur. If alignment
is correct, the shaft assembly will t into
place.
4. Install the washer (32), seal (33) and retaining ring (34). Use a seal protector when
®
23
EZT
Figure 15. Input Shaft and Bypass Rod Assembly
HYDRAULIC COMPONENTS
Refer to Figures 16-25.
Disassembly
1. Remove the bypass arm and control arm.
See page 16.
2. Drain the oil from the transaxle. See page
9.
3. Remove the side cover. See page 20.
4. Remove the reduction gears. See page
21.
5. Remove the motor shaft. See page 22.
6. Remove the input shaft and bypass rod. See
page 23.
7. (See Figure 16) Remove the swashplate
(19) and pump cylinder block (4) as one
assembly. NOTE: Removal will be aided by
applying a small amount of pressure on the
trunnion mounted swashplate towards the
center section. Also note that the control arm
(23, page 31) may be loosely assembled at
this point to assist in swashplate removal.
While gently removing the swashplate and
block assembly, keep the block face ush
with the center section to minimize damage
to the running surface.
8. (See Figure 17) Disassemble the pump cyl-
inder block (4) from the swashplate (19).
assembly (35) from the swashplate (19).
(Center Section/Filter)
12. (See Figure 20) Remove the center sec-
tion mounting screws (12). NOTE: The
center section is under motor block piston
spring pressure. These screws are factory
installed to 700 lb-in (80 Nm) and use an
anaerobic thread adhesive. A breaker bar
will be required at this step. Clean the internal threads of the mounting holes with
compressed air.
13. Remove the center section and lter assembly (57, Figure 21). NOTE: Bypass
plate (Figure 22) may slide out of the center
section.
14. Remove the lter cover by pressing in and
down on the lter cover tabs. Discard the
cover.
15. Note the location of both check plugs (56)
before removal for correct replacement
during reassembly. Remove and inspect
the check plug assemblies (56) for debris
or damage.
16. Remove the lter base (61) and discard it.
NOTE: The lter base is included in the lter
kit to be installed during reassembly of the
unit.
(Motor Block)
9. (See Figure 18) Check each piston for
proper operation by pressing the pistons in
17. (See Figure 23) Remove the motor cylinder
block assembly (6) from the housing (1).
and releasing them in the block bore. Disassemble the pump cylinder block. Check
for piston/block wear in the cylinder bore.
Inspect the pistons (A), piston springs (C)
and thrust washers (B) for excessive wear
or damage. NOTE: Thrust washers may be
held in place in the piston by residual oil.
18. Disassemble the motor cylinder block assembly (4). Check each piston for proper
operation by pressing the pistons in and
releasing them in the block bore. Disassemble the motor cylinder block. Check
for piston/block wear in the cylinder bore.
Inspect the pistons, piston springs and
10. Reassemble the pistons, springs and washers into the cylinder block and set aside.
11. (See Figure 19) Remove the thrust bearing
24 EZT
thrust washers for excessive wear or damage. NOTE: Thrust washers may be held
in place in the piston by residual oil.
®
HYDRAULIC COMPONENTS
19. Reassemble the pistons, springs and thrust
washers into the cylinder block and set
aside.
20. Remove the thrust bearing assembly (35)
from the housing (1). Inspect the thrust
bearing and thrust bearing cavity in the
housing.
Inspection
1. Inspect the pump cylinder block running
surface for wear or damage.
2. Inspect the swashplate and thrust bearing
assemblies for wear or damage.
3. Inspect the center section block running
surfaces. NOTE: These “sealing” surfaces
should be smooth in appearance without
scratches, scoring, nicks or abrasions. Drag
a ngernail across the surface to detect
uneven wear or scratches which may not
be visible.
4. Inspect the threaded check plug ports of the
center section for debris or damage.
5. Inspect the motor cylinder block running
surface for damage and wear.
6. Inspect all bearing, bushing and wear areas
in the housing.
(Center Section/Filter)
3. (See Figure 22) Install the new lter base
(61) onto the center section (57).
4. It will be necessary to clean the check plugs
prior to re-assembly. Install the check plugs
(56), in their correct location, into the center
section (57). Tighten the check plugs according to Table 6.
5. Align the tabs on the lter cover with the
slots in the lter base and carfully press the
cover onto the base until the tabs snap into
place. Insure the bypass plate (Figure 21)
is located properly in the center section.
6. (See Figures 14 & 24) Install the motor
shaft (39), pinion gear (38) and at washers
(36 & 40) into the center section (57).
7. Assemble the motor block assembly (6) onto
the motor shaft (39).
8. (See Figure 22) Install the motor shaft,
center section and motor block assembly
into the housing so that the motor block
pistons contact the thrust bearing race.
NOTE: Hold in place and insure all pistons
are still positioned correctly in the cylinder
bore by conrming spring bias against the
center section.
Assembly
(Motor Block)
hesive, insert the center section mounting
screws (12) while holding downward pressure on the center section assembly (57,
9. (See Figure 20) After applying thread ad-
1. (See Figure 23) Turn the housing (1) so
Figure 21).
the motor thrust bearing cavity is facing up.
This will assist in the installation of the motor
thrust bearing assembly (35) keeping it in
the bearing cavity during installation of the
center section assembly (57, Figure 21).
10. Tighten the center section mounting screws
(12) to the proper torque. Refer to Table
6. NOTE: The center section must be fully
seated into the pilot bore before the screws
are tightened. The center section will not self
2. Insert the thrust bearing (35) in the housing
locate.
(1). NOTE: Place the thin race of the bearing towards the housing bearing cavity. The
thick race must face the pistons.
®
25
EZT
(Swashplate/Pump Block)
11. (See Figure 19) Install the pump thrust
bearing (35) in the trunnion machined
swashplate (19). NOTE: Place the thin race
of the bearing towards the swashplate. The
thick race must face the pistons.
12. (See Figure 17) Place the pump block
assembly (4), pistons down, on top of the
thrust bearing in the swashplate (19).
13. Coat the pump running surface with clean
motor oil.
14. Care must be taken to prevent the scaring
or scratching of the center section sealing
face during this step. Insert the shaft of the
swashplate/pump block assembly (Figure
24) into the housing while simultaneously
compressing the pistons in the block.
NOTE: To assist in the installation of these
components, insert the assembly until 3/4
of the pump block is covered by the center
section. Then slightly press the shaft end
toward the center section while pushing the
shaft into its bore.
Figure 16.
19
35
15. Install the input shaft and bypass rod. See
page 23.
16. Install the axle shaft, reduction gears and
expansion plate, if removed. Refer to page
21.
17. Install the side cover and brake. See pages
18-20.
18. Fill the transaxle with new oil. See page
9.
19. Install the bypass arm and control arm. See
page 16.
4
Figure 17.
A
B
C
Figure 18
26 EZT
®
Figure 19.
Figure 20.
Figure 22.
1
35
6
Figure 23.
Figure 21.
®
27
EZT
1
4
Figure 24.
TRANSAXLE INSTALLATION
Use the following procedure to complete the
installation of the transaxle on the vehicle.
1. Install and secure the transaxle on the
vehicle according to the instructions in the
vehicle owner’s manual.
2. With the vehicle raised, install the wheels
6
19
57
39
38
on the axles, and snug the wheel hardware.
3. Lower the vehicle wheels to the ground
and torque the wheel hardware per the
vehicle owner’s manual.
Figure 25.
28 EZT
®
ASSEMBLY AFTER A COMPLETE TEARDOWN
If the unit has been torn down completely, the
following summary identies the assembly procedures necessary to completely assemble the
unit. Each assembly procedure is located by a
page reference.
The part reference numbers provided in each
assembly procedure are keyed to the individual
exploded views, and are also keyed to the complete unit exploded view on page 30.
1. Install the hydraulic components. See
pages 24-28.
2. Install the input shaft and bypass rod. See
page 23.
3. Install the axle shaft, reduction gears and
expansion plate. See page 21.
4. Install the cog brake and side cover. See
page 18-20.
5. Fill the transaxle with new oil. See page 9.
6. Install the bypass arm and control arm.
See page 16.
7. Install the transaxle onto the vehicle.
8. Perform the purge procedures listed on
page 10.
®
29
EZT
SEALANT APPLICATION
NOTE: Prior to applying the new sealant, the
old sealant must be removed from all surfaces.
A small consistent bead of the sealant around
the housing face will be sufcient. Use sparingly.
The illustration below indicates the correct
areas.
30 EZT
®
NOTES
®
31
EZT
159
158
160
74
75
157
156
154
73
2X 155
153
151
2X 150
100
55
DISC BRAKE
BRAKE KIT
W/ SPRING
OR
100
14*
144
36
55
71
71
75
74
72
72
72
73
73
73
71
55
55
74
70
71
72
74
73
73
74
71
55
BRAKE KIT
THROUGH HOLE
BRAKE KIT
CLEVIS PIN
BRAKE KIT
TOP MOUNT
OR
OR
OR
37*
38
39
40
64
62
63
3
56
60
61
57
35
6
4
35
19
2
16X 9
68
10*
41
44
43
42
3X 12
41
45*
46
47
48
67
2X 65
THICK RACE TOWARD
PISTONS
2X 8
1
20*
66
53
13*
29
28
27
7
30
31*
32
34*
33*
49
50
51*
34*
124
99
25
59
18*
17
16*
15
14*
127
138
128
126
139
54
54
54
122
122
122
123
123
120
120
120
121
119
121
121
3X 130
6X 131
3X 123
OR
OR
OR
200
200
200
26
26
24
24
24
135
134
141
23
131
140
5
22
22
21
21
23
23
25
25
EZT® EXPLODED VIEW
NOTES:
1. BRAKE AND CONTROL ARM CAN BE ON EITHER
SIDE.
2. LH SIDE SHOWN. RH SIDE IS A MIRROR IMAGE.
ITEMS NOT SHOWN
11 - OIL, 20W50
58 - SEALANT TUBE (10.3 oz)
52 - KIT, SEAL
145 - ASSEMBLY, HUB PULLER
Figure 24. EZT
®
32 EZT
®
EZT® ITEMS LIST
No. DESCRIPTION
1 ASSEMBLY, MAIN HOUSING
BUSHING
2 ASSEMBLY, SIDE COVER
BUSHING
3 PLATE, BYPASS
4 ASSEMBLY, PUMP BLOCK
BLOCK, CYLINDER
PISTONS
SPRINGS, COMPRESSION
WASHERS, THRUST
5 SPACER
6 ASSEMBLY, MOTOR BLOCK
7 PLUG, 9/16-1
8 PIN, STAINLESS, HEADLESS
9 HFHCS 1/4-20 X 1.25 (SELF-TAPPING)
10 SEAL, LIP
12 BOLT, HEX FLANGE 3/8-24 X 2.5
13 SEAL, LIP
14 RING, RETAINING
15 ROD, BYPASS
16 RING, RETAINING
17 ARM, BYPASS
18 RING, RETAINING (PUSHNUT)
19 SWASHPLATE, TRUNNION, MACHINED
20 SEAL, LIP
21 STUD
22 WASHER
23 ARM, CONTROL
24 WASHER, FLAT
25 TWHCS 5/16-24 X 1.0
26 NUT, HEX LOCK 5/16-24 UNJF
27 SPRING-HELICAL COMPRESSION
28 WASHER
29 SHAFT, INPUT
30 BEARING, BALL
31 RING, RETAINING WIRE
32 SPACER
33 SEAL, LIP
34 RING, RETAINING
35 BEARING, THRUST
36 WASHER, FLAT
37 RING, RETAINING
38 GEAR, PINION, 13T
39 SHAFT, MOTOR
40 WASHER, MOTOR SHAFT
41 WASHER, HT
42 GEAR, 10T/48T
43 GEAR, 10T JACKSHAFT
44 PIN, JACKSHAFT
45 RING, SPIRAL RETAINING
46 GEAR, 52T BULL
47 WASHER
48 BEARING, SLEEVE (INBOARD)
49 AXLE
50 BUSHING
51 SEAL, LIP
52 KIT, SEAL
53 KIT, EXPANSION PLATE
54 KIT, FAN-PULLEY
No. DESCRIPTION
55 KIT, BRAKE ASSEMBLY
56 CHECK PLUGS
57 KIT, CENTER SECTION-FILTER
59 KIT, BYPASS ARM
60 ASSEMBLY, COVER
61 KIT, FILTER
62 FILTER, BASE
63 CENTER SECTION
64 MAGNET
65 SCREW, 10-32 X 1/2 (SELF-TAPPING)
66 HOUSING, MAIN
67 PLATE, EXPANSION
68 COVER, SIDE
70 PIN, CLEVIS
71 BUSHING
72 WASHER
73 SCREW
74 ARM, BRAKE
75 SPRING
99 NUT, PIN LOCKING
100 ROTOR
119 HUB
120 FAN
121 PULLEY
122 NUT, HEX LOCK
123 WASHER OR CAPSCREW 1/4-20
124 HUB KIT
126 FITTING
127 HOSE, EXPANSION TANK
128 CAP, BARBED VENT
130 NUT, HEX 1/4-20
131 SPACER OR CAPSCREW 5/16-20 X 1
134 WASHER
135 SPRING
138 KIT, BREATHER ASSEMBLY
139 KIT, BREATHER ASSEMBLY
140 ARM, NEUTRAL
141 RTN
144 DEFLECTOR, BELT
150 PUCK, BRAKE
151 PLATE, PUCK
153 ASSEMBLY, BRAKE YOKE
154 SPACER
155 PIN, BRAKE
156 SPRING, BRAKE COMPRESSION
157 CAPSCREW, 1/4-20 X 2.0
158 WASHER
159 NUT, CASTLE 5/16-24
160 PIN, COTTER
200 KIT, RTN
®
33
EZT
GLOSSARY OF TERMS
Axial Piston: Type of design for hydraulic motors and pumps in which the pistons are arranged
parallel with the spindle (input or output shaft).
Bantam Duty: A descriptive term relating to the product capacity (meaning: light duty).
Bypass Valve: A valve whose primary function is to open a path for the uid to bypass the motor
or pump. Also referred to occasionally as the freewheel valve or dump valve.
Case Drain Line (Return Line): A line returning uid from the component housing to the reser-
voir.
Cavitation: A concentrated gaseous condition within the uid causing the rapid implosion of a
gaseous bubble.
Center Section: A device which acts as the valve body and manifold of the transmission.
Charge Pump: A device which supplies replenishing uid to the uid power system (closed
loop).
Charge Pressure: The pressure at which replenishing uid is forced into a uid power system.
Charge Relief Valve: A pressure control valve whose primary function is to limit pressure in the
charge circuit.
Check Valve: A valve whose primary function is to restrict ow in one direction.
Closed Loop: A sealed and uninterrupted circulating path for uid ow from the pump to the
motor and back.
Decay Rate: The ratio of pressure decay over time.
End Cap: See “Center Section”
Entrained Air: A mechanically generated mixture of air bubbles having a tendency to separate
from the liquid phase.
Gerotor: A positive displacement pump frequently used as a charge pump.
Hydraulic Motor: A device which converts hydraulic uid power into mechanical force and mo-
tion by transfer of ow under pressure.
Hydraulic Pump: A device which converts mechanical force and motion into hydraulic uid power
by producing ow.
Hydrostatic Pump: See “Hydraulic Pump”
Hydrostatic Transaxle: A multicomponent assembly including a gear case and a hydrostatic
transmission.
34 EZT
®
Hydrostatic Transmission: The combination of a hydraulic pump and motor in one housing to
form a device for the control and transfer of power.
Inlet Line: A supply line to the pump.
Integrated Zero-Turn Transaxle: The combination of a hydrostatic transmission and gear case
in one housing to form a complete transaxle.
Manifold: A conductor which provides multiple connection ports.
Neutral: Typically described as a condition in which uid ow and system pressure is below that
which is required to turn the output shaft of the motor.
Pressure Decay: A falling pressure.
Priming: The lling of the charge circuit and closed loop of the uid power system during start
up, frequently achieved by pressurizing the uid in the inlet line.
Purging: The act of replacing air with uid in a uid power system by forcing uid into all of the
components and allowing the air a path of escape.
Rated Flow: The maximum ow that the power supply system is capable of maintaining at a
specic operating pressure.
Scoring: Scratches in the direction of motion of mechanical parts caused by abrasive contaminants.
Swash Plate: A mechanical device used to control the displacement of the pump pistons in a
uid power system.
System Charge Check Valve: A valve controlling the replenishing ow of uid from a charge
circuit to the closed loop in a uid power system.
System Pressure: The pressure which overcomes the total resistance in a system, including all
efciency losses.
Valve: A device which controls uid ow direction, pressure, or ow rate.
Variable Displacement Pump: A pump in which the displacement per revolution can be var-
ied.
Volumetric Displacement: The volume for one revolution.
®
35
EZT
©2010 Hydro-Gear
Printed in U.S.A.
Rev. P8
36 EZT
®
Loading...