HGM-H™ Series Motor Service and Repair Manual BLN-0043 July 2011
TABLE OF CONTENTS Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . �������1 Assembly After a Complete Teardown . . . . . . . . �����23 Description and Operation . . . . . . . . . . . . . . . . . �������2 Drive Motor Exploded View. . . . . . . . . . . . . . . . . �����24 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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. Internal repair procedures require that the HGM-H series motor be removed from the vehicle.
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 specifications, 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.
HGM-H 3
EXTERNAL FEATURES HGM-H SERIES MOTORS “B” PORT WHEEL HUB “A” PORT HYDRAULIC HOUSING CAP HUB NUT COVER BRAKE ARM FILL PORT / OPTIONAL CASE DRAIN — Top View— MOUNTING HOLE X 4 “B” PORT “A” PORT BRAKE ARM — Back View— “A” & “B” PORTS WHEEL HUB BRAKE ARM HUB NUT COVER FILL PORT / OPTIONAL CASE DRAIN — Side View— Figure 1, External Features 4 HGM-H
TECHNICAL SPECIFICATIONS HGM-H ™ P iston M otor TECHNICAL SPECIFICATIONS Geometric Displacement Maximum Speed 15 in3/rev (245.81 cc/rev) 18 in3/rev (294.97 cc/rev) Continuous 210 rpm 185 rpm Intermittent 250 rpm 210 rpm Peak 6600 in-lbf (75 N-m) 7900 in-lbf (89 N-m) Continuous 2700 in-lbf (30 N-m) 3200 in-lbf (36 N-m) Intermittent 4900 in-lbf (75 N-m) 5900 in-lbf (64 N-m) Maximum Torque Maximum Oil Flow Continuous 9.4 hp (7 KW) Intermittent 20.5 hp (15.4 kW) Axle Shaft Diameter 1.
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.
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! Follow all safety procedures outlined in the vehicle owner’s manual. In many cases, problems with a hydraulic systems 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.
SERVICE AND MAINTENANCE EXTERNAL MAINTENANCE Regular external maintenance of the hydraulic motor 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 reservoir oil level in accordance with the vehicle manufacturers recommendations. 3. Inspect the vehicle drive belt, idler pulley(s), and idler spring(s). Insure that no belt slippage can occur.
SERVICE AND MAINTENANCE PURGING PROCEDURE The HGM-H motor can not be purged of air as a stand alone component. The hydraulic system as a whole will need to be purged after any addition of oil to the system or a complete oil change. This will most likely involve the use of the hydraulic pumps bypass feature. If this is not available, see the manufacturers recommendation for air purging.
TEAR DOWN AND REASSEMBLY HOW TO USE THIS MANUAL Each subassembly illustrated in this manual is illustrated with an exploded view showing the parts involved. The item reference numbers in each illustration are for assembly instructions only. See page 25 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.
TOOLS Miscellaneous R E QUIRED TOOL S Three Jaw Puller Flat Blade Screw Driver (2) Torque Wrench Air Impact Wrench Rubber or Neoprene Mallet Breaker Bar Side Cutters/Snips Needle Nose Pliers Large External Snap Ring Pliers Small Internal Snap Ring Pliers 1/2”-3/8” Adapter 3/8” Deep 1-1/8” Deep 1/4” Allen 3/4” Deep Sockets TORQUES Item Description 4 10 56 80 HGM-H R E Q U I R E D TORQUE VAL UES Screw, Housing Nut, Axle, Castlelated Nut, Brake Plug 9/16-16 (Metal) Torque Operation 280-340 in-lbs (3
MOTOR REMOVAL NOTE: It is necessary to remove the HGM-H Motor from the vehicle before performing the repair procedures presented in this section. Before starting any disassembly, make certain that your work area is neat and clean. Clean the external parts of the transaxle. The following procedures are presented in the order recommended for a complete tear down of the transaxle. Do not disassemble the unit any farther than necessary to accomplish the required repairs.
AXLE HUB ASSEMBLY Refer to Figure 4 Assembly 1. Remove the axle cap and discard (9). 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the cotter pin and discard (18). 3. Remove the castle nut (10). 4. Remove the taper hub assembly (11) and discard. NOTE: A new hub will have to be ordered to replace the discarded hub. 5. Remove the axle shaft key (17). 2. When tightening the castle nut (10)*, refer to the table on page 11 for the required torque values.
BRAKE ARM ASSEMBLY Refer to Figure 5 Disassembly Assembly 1. Remove all items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly. 2. Mark the orientation of the brake arm (59) before removal. 2. Install new seal (58) from seal kit. 3. Remove the retaining ring (60). 4. Remove the brake handle (59), spring (82) and spring pin (83). 5. Remove the spring spacer (81) and brake spacer (57). 5. Remove the dowel pin (84) and the seal (58).
SIDE HOUSING Refer to Figure 6 Disassembly Assembly 1. Remove all external items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the seal (13) and discard. 2. Apply a bead of sealant around the perimeter of the middle housing face. See “Sealant Application Diagram” on page 21. 3. Remove the twelve housing screws (4), then separate axle housing (1) from middle housing (2).
AXLE SHAFT AND PLANETARY GEAR SET Refer to Figures 7 and 8 Disassembly Assembly 1. Remove all external items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly. NOTE: Note the location of the ring gear tabs. 2. Remove the axle bearing (14) and washer (15). 2 Ring Gear Tabs Ring Gear 3. Remove the ring gear (21). 4. Remove the axle shaft (16) and planetary assembly from the middle housing (2). 5.
BEARING AND MOTOR BLOCK CAP Refer to Figure 9 Disassembly 1. Remove all external items previously discussed in their recommended order. 2. Remove the seven housing cap screws (4) and the housing cap (3). Assembly 1. Reassemble all parts in the reverse order of disassembly. 3. Remove the o-ring (6) and discard. 2. Install new o-ring (6) and retaining ring (47) from seal kit. 4. Remove the thrust bearing (45), retaining ring (47) and washer (46). Discard the retaining ring (47) 3.
MOTOR BLOCK Refer to Figure 10 Disassembly Assembly 1. Remove all external items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the motor block assembly (40) from the middle housing (2). 2. Apply a light coating of oil to all running surfaces to prevent scoring during reassembly. 3. Disassemble the motor block assembly and inspect all parts. Inspection 1.
MOTOR SHAFT AND AXLE BEARING Refer to Figure 11 Disassembly Assembly 1. Remove all external items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the motor shaft (34), retaining ring (30) and gear (31) out of the middle housing (2). 3. Remove the brake rotor (32) and the washer (33). 4. Remove the inboard axle bearing (27). Inspection 1. Inspect for scratches and or damage to the brake rotor (32). 3.
BRAKE SHAFT AND CAM Refer to Figure 12 Disassembly Inspection 1. Remove all external items previously discussed in their recommended order. 1. Inspect the puck (54) for excessive wear. 2. Inspect all components for wear or damage. NOTE: If the brake is working properly and the brake components are not damaged, there is no need to remove the brake assembly. Assembly 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the brake shaft nut (56) and washer (55). 2.
SCREW TIGHTENING SEQUENCE 7 1 3 12 4 5 10 5 1 2 6 3 8 7 9 6 11 4 2 Figure 13, Side Housing Bolt Sequence Figure 14, Motor Housing Cap Bolt Sequence SEALANT PATH Figure 15, Sealant Path HGM-H 21
CASTLE NUT (10) ALTERNATE TORQUE METHOD NOTE: The ideal method for installing a new hub and nut is utilizing a torque wrench capable of 275 ft-lbs. If a 275 ft-lbs torque wrench is not available please use the alternative procedure outlined in this document. All parts need to be clean and free of lubrication. Procedure: Tools: 1. Air Compressor and Air Impact Wrench or Electric Impact Wrench (REMOVAL ONLY) 1. Engage machine parking brake. 2. 1 7/16” Socket 3. Remove existing nut. 3.
ASSEMBLY AFTER A COMPLETE TEARDOWN If the unit has been torn down completely, the following summary identifies 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 24. 8. Apply sealant material onto housing middle housing (2). Page 21 9.
HGM-H MOTOR EXPLODED VIEW 24 HGM-H
HGM-H MOTOR PARTS LIST 1 2 3 4 6 9 10 11 13 14 15 16 17 18 20 21 22 23 24 25 26 27 30 31 32 33 34 40 45 46 47 50 51 52 53 54 55 56 57 58 59 60 71 80 81 82 83 84 HGM-H Housing, Axle Housing, Middle Housing, Motor Block Screw, Housing O-ring, Motor Housing Cap, Axle Nut, Axle Hub, Taper (1.25, 4 Bolt / 1.
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). Bypass Valve: A valve whose primary function is to open a path for the fluid 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 fluid from the component housing to the reservoir.
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 fluid flow and system pressure is below that which is required to turn the output shaft of the motor. Pressure Decay: A falling pressure.
NOTES 28 HGM-H
NOTES HGM-H 29
© 2011 HYDRO-GEAR Printed in U.S.A. Rev.
