Toro 74310, 74311, 74312, 74313 Service Manual
HGM-H™ Series Motor
Service and Repair Manual
BLN-0043
July 2011
TABLE OF CONTENTS
Foreword ............................... . . . .1
Description and Operation ................. . . . .2
Introduction ............................. . . . .2
General Description ......................... 2
External Features ........................ . . . .4
Technical Specifications ...................... 5
Product Identification ........................ 5
Safety .................................... 6
Personal Safety .......................... . . . .6
Tool Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Work Area Safety ........................ . . . .6
Troubleshooting .......................... . . . .7
Work Area Safety ........................ . . . .8
Service and Maintenance .................. . . . .8
External Maintenance ..................... . . . .8
Service and Maintenance Procedures ........ . . . .8
Fluids .................................. . . . .8
Assembly After a Complete Teardown ........ . . .23
Drive Motor Exploded View ................. . . .24
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . 26-27
Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28-29
Fluid Volume and Level .................... . . . .8
Fluid Change Procedure ................... . . . .8
Purge Procedure ......................... . . . .9
Tear Down and Reassembly ................ . . .10
How to Use This Manual ................... . . .10
General Instructions ...................... . . .10
Tools .................................. . . . 11
Torques ................................ . . .11
Hydraulic Motor Removal .................. . . .12
Axle Hub Assembly ....................... . . .13
Brake Arm Assembly ...................... . . .14
Side Housing ............................ . . .15
Axle Shaft and Planetary Gear Set ........... . . .16
Bearing and Motor Block Cap ............... . . .17
Motor Block ............................. . . . 18
Motor Shaft and Brake Disc ................ . . . 19
Brake Shaft and Cam ..................... . . .20
Screw Tightening Sequence ................ . . .21
Sealant Path ............................ . . .21
Castle Nut Alternate Torque Method .......... . . .22
HGM-H i
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® HGM-H™
series motor.
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.
Internal repair procedures require that the
HGM-H series motor 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 the EETC (Equipment and Engine
Training Council) at (262) 367-6700 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.
HGM-H 1
DESCRIPTION AND OPERATION
INTRODUCTION
The purpose of this manual is to provide information useful in servicing the Hydro-Gear®
HGM-H series motor. This manual includes
the HGM-H series motor general description,
hydraulic schematic, technical specications,
servicing and troubleshooting procedures.
Should servicing be required, the exterior of the
motor 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 HGM-H series hydraulic motors are xed
displacement axial piston motors. The motor
is designed to convert hydraulic power into rotational power at the axle shaft. It operates at
an innitely variable speed range between zero
and maximum axle speed determined by motor
displacement and maximum pump ow in both
forward and reverse modes of operation.
movement out of the cylinder block, it gets
pushed back into the cylinder and uid inside
the piston is discharged through the low pressure port of the motor. Pistons develop torque
only through half of the cylinder block rotation
cycle. Therefore, multiple pistons are used to
provide a constant and continuous torque to
the motor shaft. Reversing the direction of the
incoming pressurized uid into the motor reverses the direction of the motor output rotation.
A hydraulic bypass is utilized in a hydraulic
system 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. The bypass will be
located on the hydraulic pump.
The HGM-H series motor utilizes a friction
type brake controlled by a cam attached to an
external actuating arm.
The HGM-H series motor is available with a
xed displacement of 15 cu. in. or 18 cu. in. (245
to 294 cc) maximum per revolution. The cylinder
block pistons in the HGM H series motors are
set at a xed displacement by a swash angle
that is integral to the motor housing. Therefore,
the motor is always at maximum displacement.
As pressurized uid from the pump pushes
against the cylinder block pistons, they forced
to rotate with the thrust bearing. As the pistons
rotate with the thrust bearing, they create torque
and rotory motion that is transmitted to the axle
shaft. Torque continues to develop as long as
the piston is being pushed out of the cylinder
block. When the piston reaches the end of the
2 HGM-H
HGM-H 3
EXTERNAL FEATURES HGM-H SERIES MOTORS
WHEEL HUB
HUB NUT COVER
“B” PORT
“B” PORT
“A” PORT
HYDRAULIC HOUSING CAP
BRAKE ARM
FILL PORT / OPTIONAL CASE DRAIN
— Top View—
MOUNTING HOLE X 4
“A” PORT
WHEEL HUB
HUB NUT COVER
BRAKE ARM
— Back View—
“A” & “B” PORTS
BRAKE ARM
FILL PORT / OPTIONAL CASE DRAIN
— Side View—
Figure 1, External Features
4 HGM-H
TECHNICAL SPECIFICATIONS
HGM-H™ Piston Mo to r tECHniCAL sPECiFiCAtions
Geometric Displacement
Maximum Speed
Continuous
Intermittent
Maximum Torque
Peak
Continuous
Intermittent
Maximum Oil Flow
Continuous
Intermittent
Axle Shaft Diameter
Axle Shaft End Options
Parking Brake Type
Max. weight applied to shaft/housing
Wheel Load Force - Radial
Weight of Unit
15 in3/rev (245.81 cc/rev) 18 in3/rev (294.97 cc/rev)
210 rpm
250 rpm
6600 in-lbf (75 N-m)
2700 in-lbf (30 N-m)
4900 in-lbf (75 N-m)
9.4 hp (7 KW)
20.5 hp (15.4 kW)
1.375 in (34.925 mm)
4 Bolt Flange
5 Bolt Flange
Internal Wet Disc
840 lbf (381 kg)
38.2 lb (17.3 kg)
185 rpm
210 rpm
7900 in-lbf (89 N-m)
3200 in-lbf (36 N-m)
5900 in-lbf (64 N-m)
PRODUCT IDENTIFICATION
The model and conguration of the HGM-H can be determined from the label found on the
transaxle.
HYDRO-GEAR
Model Number
HGM-15H-XXCK
1 192 X 10428
Year Built
Date (Julian- Day of year)
Serial Number (unique for that model - for that day)
Type of Product and Build Information
Figure 2, Product Label
Assembled in USA
HGM-H 5
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 hydraulic motor. When you see this
symbol - HEED ITS WARNING.
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
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
hydraulic motor, fully read and understand the safety precautions described
in this section.
PERSONAL SAFETY
Certain safety precautions must be observed
while servicing or repairing the hydraulic motor.
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.
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.
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.
6 HGM-H
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.
TROUBLESHOOTING
In many cases, problems with a hydraulic sys-
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.
TROUBLESHOOTING CHECKLIST
Possible Cause Corrective Action
Unit Operates In One Direction Only
Control linkage bent or out of adjustment Repair or replace linkage on vehicle pump assembly, Page 8
Drive belt slipping or pulley damaged Repair or replace belt/pulley on vehicle pump assembly, Page 8
Vehicle Does Not Drive/Track Straight
Vehicle tires improperly inated Refer to vehicle manufacturer suggested tire pressure
Control linkage bent or out of adjustment Repair or replace linkage on vehicle pump assembly, Page 8
Drive belt slipping or pulley damaged Repair or replace belt/pulley on vehicle pump assembly, Page 8
Brake Partially Engaged Disengage Brake, Replace damaged brake components, Page 14
Unit Is Noisy
Oil level low or contaminated oil Fill to proper level or change oil, Page 8
Excessive loading Reduce vehicle loading, Page 8
Loose parts Repair or replace loose parts
Air trapped in hydraulic system Purge hydraulic system, Page 9
Brake Partially Engaged Disengage Brake, Replace damaged brake components, Page 14
Unit Has No/Low Power
Engine speed low Adjust to correct setting
Control linkage bent or out of adjustment Repair or replace linkage on vehicle pump assembly, Page 8
Drive belt slipping or pulley damaged Repair or replace belt/pulley on vehicle pump assembly, Page 8
Oil level low or contaminated oil Fill reservoir to proper level or change oil, Page 8
Excessive loading Reduce vehicle loading, Page 8
Air trapped in hydraulic system Purge hydraulic system, Page 9
Brake Partially Engaged Disengage Brake, Replace damaged brake components, Page 14
Unit Is Operating Hot
Debris buildup around transaxle Clean off debris, Page 8
Oil level low or contaminated oil Fill to proper level or change oil, Page 8
Excessive loading Reduce vehicle loading, Page 8
Air trapped in hydraulic system Purge hydraulic system, Page 9
Brake Partially Engaged Disengage Brake, Replace broken, missing or frozen return spring
Transaxle Leaks Oil
Damaged seals, housing, or gaskets Replace damaged components
Air trapped in hydraulic system Purge hydraulic system, Page 9
tems are not related to a defective hydraulic
unit, 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 Service and Maintenance, before assuming
the hydraulic system is malfunctioning. The
table below provides a troubleshooting checklist to help determine the cause of operational
problems.
HGM-H 7
Loading...