We set the wheels in motion.
Table of Contents Section Page Foreword .............................................................................................................................. i Description and Operation ................................................................................................ 1 Introduction .................................................................................................................................................. 1 General Description ..................................
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. the mechanics to be supplied with the latest information available. All repair procedures illustrated in this guide are suggested, but preferred methods of repair.
SECTION 1. DESCRIPTION AND OPERATION INTRODUCTION The purpose of this manual is to provide information useful in servicing the Hydro-Gear Bantam Duty Pumps (BDP’s). This manual includes the BDP’s general descriptions, hydraulic schematics, technical specifications, servicing and troubleshooting procedures for BDP models 10A, 16A and 21L. The BDP’s normally will not require servicing during the life of the vehicle in which it is installed.
EXTERNAL FEATURES BDP-10A SAE "A" PAD FLANGE STYLE TRUNNION ARM CHARGE PRESSURE DIAGNOSTIC PORT INLET INPUT SHAFT "A" and "B" PORTS STANDARD CHECK VALVE STANDARD CHECK ORVALVE SHOCK VALVE OR SCR CASE DRAIN OPTION CHARGE COVER STANDARD CHECK VALVE STANDARD CHECK OR SHOCK VALVEVALVE OR SCR BYPASS VALVE TRUNNION ARM CASE DRAIN OPTION Figure 1.
EXTERNAL FEATURES BDP-16A BYPASS VALVE SAE “A” PAD FLANGE STYLE TRUNNION ARM INPUT SHAFT INLET CHARGE PRESSURE DIAGNOSTIC PORT “A” and “B” PORTS SYSTEM CHECK VALVE OR SHOCK VALVE SYSTEM CHECK VALVE OR SHOCK VALVE CASE DRAIN BYPASS VALVE CHARGE COVER CASE DRAIN Figure 2.
EXTERNAL FEATURES BDP-21L SAE "B" PAD FLANGE STYLE TRUNNION ARM "A" and "B" PORTS INPUT SHAFT CHARGE PRESSURE DIAGNOSTIC PORT INLET CASE DRAIN BYPASS VALVE STANDARD CHECK VALVE STANDARD CHECK OR SHOCK VALVE VALVE OR SCR CHARGE COVER STANDARD CHECK VALVE STANDARD CHECK OR SHOCK VALVE OR VALVE SCR Figure 3.
HYDRAULIC SCHEMATIC SYSTEM CHECK & RELIEF VALVE OPTIONS: 1) NO SCR, NO BLEED 2) NO SCR, .024” BLEED 3) NO SCR, .031” BLEED 4) NO SCR, .044” BLEED 5) 3000 PSI SCR, NO BLEED (BDP-10A/16A) 3000 PSI SHOCK, NO BLEED (BDP-10A/16A) 6) 3000 PSI SHOCK, .024” BLEED (BDP-10A/16A) 7) 3000 PSI SCR, .031” BLEED (BDP-10A/16A) 3000 PSI SHOCK, .031” BLEED (BDP-10A/16A) 8) 3000 PSI SHOCK, .044” BLEED (BDP-10A/16A) PORT A PORT B CHARGE DIAGNOSTIC CHARGE PUMP INLET BYPASS VALVE BLEED OPTIONS: 1) NO BLEED ORIFICE 2) .
HYDRAULIC SCHEMATIC 9) SHOCK, .031” BLEED ORIFICE 10) SHOCK, .044” BLEED ORIFICE SCR, NO BLEED ORIFICE 6) SCR, .031” BLEED ORIFICE 7) SHOCK, NO BLEED ORIFICE 8) SHOCK, .024” BLEED ORIFICE 3) .043” BLEED ORIFICE Figure 6. BDP-21L With Standard Charge Pump Hydraulic Schematic SCR, NO BLEED ORIFICE 6) SCR, .031” BLEED ORIFICE 7) SHOCK, NO BLEED ORIFICE 8) SHOCK, .024” BLEED ORIFICE 9) SHOCK, .031” BLEED ORIFICE 10) SHOCK, .044” BLEED ORIFICE 3) .043” BLEED ORIFICE Figure 7.
GRAPHICAL SCHEMATIC Figure 8. BDP-10A,16A and 21L Standard Charge Pump Graphical Schematic Figures 4-7 represent hydraulic schematics of the standard charge and auxiliary charge pump. Figure 8 provides a graphical illustration of the hydraulic oil circuit. The input shaft and pump cylinder block are turned in one direction only by the engine/ drive belt/ pulley combination or direct drive gear box.
TECHNICAL SPECIFICATIONS Displacement BDP-10A BDP-16A BDP-21L 0.623 in3 / rev (10.2 cc / rev) 7.6 gpm@3000 rpm (1000 psi) 0.97 in3 / rev (16 cc / rev) 12 gpm@3000 rpm (1000 psi) 1.33 in3 / rev. (21.8 cc / rev) 16.
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 BDP’s. 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.
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! Follow all safety procedures outlined in the vehicle owner’s manual! In many cases problems with the BDP-10A, 16A and 21L are not related to a defective pump but are caused by slipping drive belts, partially engaged bypass valves, and loose or damaged control linkages.
BDP FLOW TEST KIT INSTRUCTIONS BLN-51334 FEBRUARY 2003 (This Instruction Sheet supersedes all previous flow testing instructions) Description: BDP Flow Test Kit (Part Number 70661) (Part Number 70661 Supersedes Part Numbers 70511 and BB-76810) Purpose: The design purpose of the BDP Flow Test Kit is to allow the dealer to isolate the BDP from the wheel motor and determine if the BDP is faulty. The following information can be used to install and test the BDP by simulating a wheel motor load.
Note: Raising the system oil temperature will make a difference in the readings you receive. It has been determined that to complete this test accurately, the oil temperature must be near system operating temperatures. Suggested temperature range 160°- 210°F (71.1° - 98.9°C) 8. On the BDP-10A/10L, BDP-16A and BDP-21L tighten the restriction valve until you read 300 psi (21 bar). Record the flow reading from the Bi-Directional Flow Meter. 9.
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 BDP should include the following: 8. Inspect the vehicle control linkage to the directional control arm on the BDP. Also, insure the control arm is securely fastened to the trunnion arm. 9.
FLUID VOLUME AND LEVEL Certain situations may require additional fluid to be added or even replaced. Refer to the vehicle manufacturer’s recommendations for the proper fill location and level. After maintenance or oil change, follow purging procedures below and recheck the fluid level once the unit has been operated for approximately 1 minute. FLUID CHANGE In the event of oil contamination or degradation, oil addition or change may alleviate certain performance problems.
SECTION 5. REPAIR HOW TO USE THIS MANUAL Each assembly is provided with an exploded view showing the parts involved. The item reference numbers in each illustration are for assembly instructions only. See pages 35-40 for part names and descriptions. A complete exploded view and item list of the pump is provided at the end of this section. GENERAL INSTRUCTIONS Cleanliness is a primary means of assuring satisfactory life on repaired pumps.
Table 4. BDP-10A Plug Fitting Torque Values Item # or Description Case Drain (fitting torque) System Port (fitting torque) Inlet (fitting torque) 42A, 42B, Check Valves/Shock Valves 42A, 42B, Check Reliefs (cap) 15, Bypass Valve 56, Diagnostic Plug 10, Cap Screw (non-auxiliary) 4, End Cap Bolts Torque 200-250 lb-in (22.6-28.2 N-m) 370-470 lb-in (41.8-53.1 N-m) 200-250 lb-in (22.6-28.2 N-m) 180-240 lb-in (20.3-27.1 N-m) 200-275 lb-in (22.6-31.0 N-m) 84-120 lb-in (9.5-13.6 N-m) 84-120 lb-in (9.5-13.
REMOVAL, INSPECTION AND/OR REPLACEMENT OF INPUT SHAFT SEAL BDP-10A REMOVAL, INSPECTION AND/OR REPLACEMENT OF INPUT SHAFT SEAL BDP-16A/21L Refer to Figure 10. Refer to Figure 11. Disassembly BDP-10A Disassembly BDP-16A/21L 1. Remove retaining ring (22) from housing. 1. Remove retaining ring (3) from housing (15). 2. Remove lip seal (20). Care must be taken to prevent damage to the housing bore, shaft sealing surface, or bearing. Once removed, the seal is not reusable. 2. Remove lip seal (6).
REMOVAL, INSPECTION AND/OR REPLACEMENT OF TRUNNION ARM (CONTROL ARM) SEAL BDP-10A/16A REMOVAL, INSPECTION AND/OR REPLACEMENT OF TRUNNION ARM (CONTROL ARM) SEAL BDP-21L Refer to figure 12. Refer to figure 13. Disassembly BDP-10A/16A Disassembly BDP-21L 1. Remove the retainer and lip seal (49/12) from the housing (1/15). Care must be taken to prevent damage to the housing trunnion bore, trunnion arm (37/13) and sealing surface. Once removed the retainer and lip seal is not reusable. 1.
REMOVAL, INSPECTION AND/OR REPLACEMENT OF CHECK VALVES BDP-10A/16A REMOVAL, INSPECTION AND/OR REPLACEMENT OF CHECK VALVES BDP-21L Refer to Figure 14. Refer to Figure 15. Disassembly BDP-10A/16A Disassembly BDP-21L Perform disassembly, inspection and assembly on check valves one side at a time. Some units vary in “A” side to “B” side check configuration. Perform disassembly, inspection and assembly on check valves one side at a time. Some units vary in “A” side to “B” side check configuration. 1.
REMOVAL, INSPECTION AND/OR REPLACEMENT OF SYSTEM CHECK RELIEFS (SCR’s) OR SHOCK VALVES BDP-10A/16A REMOVAL, INSPECTION AND/OR REPLACEMENT OF SYSTEM CHECK RELIEFS (SCR’s) OR SHOCK VALVES BDP-21L Refer to Figure 16. Refer to Figure 17. Disassembly BDP-10A/16A Disassembly BDP-21L Perform disassembly, inspection and assembly on SCR/shock valve one side at a time. Some units vary in “A” side to “B” side configuration. Perform disassembly, inspection and assembly on SCR/shock valve one side at a time.
REMOVAL, INSPECTION AND/OR REPLACEMENT OF THE BYPASS BDP10A/16A REMOVAL, INSPECTION AND/OR REPLACEMENT OF THE BYPASS BDP21L Refer to Figure 18. Refer to Figure 19. Disassembly BDP-10A/16A Disassembly BDP-21L 1. Loosen the bypass valve (15/50) using a 5/8” wrench. 1. Loosen the bypass valve (50) using a 5/8” wrench. 2. Remove the bypass (15/50) from the BDP end cap (2/25). 2. Remove the bypass (50) from the BDP end cap (25). Inspection BDP-10A/16A Inspection BDP-21L 1.
REMOVAL, INSPECTION AND ASSEMBLY OF THE STANDARD CHARGE PUMP BDP-10A Refer to Figure 20. Disassembly BDP-10A 1. Prior to removal of the charge cover, place a mark on the charge cover and end cap for realignment. 2. Using a 5 mm allen wrench, loosen the charge cover bolts (10) from the BDP end cap (2). While holding the charge cover in place, remove the charge cover bolts (10). 3. Remove the charge cover, O-ring, gerotor items (6), charge spring and charge ball (44). Inspection BDP-10A 1.
REMOVAL, INSPECTION AND ASSEMBLY OF THE STANDARD CHARGE PUMP BDP-16A/21L Refer to Figure 21. Disassembly BDP-16A/21L 1. Prior to removal of the charge cover, place a mark on the charge cover and end cap for realignment. 2. Using a 1/2” wrench loosen the charge cover bolts from the BDP end cap (25). While holding the charge cover in place, remove the charge cover bolts (56). 3. Remove the charge cover, O-ring, gerotor items (40), charge spring and charge ball (44). Inspection BDP-16A/21L 1.
REMOVAL, INSPECTION AND ASSEMBLY OF THE END CAP AND VALVE PLATE BDP-10A Refer to Figure 22. This is normal. Grooving in the plate, or material transfer that is evident when the surface is checked by dragging a fingernail across it, would be cause for replacement of the valve plate. 3. Inspect and replace alignment pins (3) if bent or distorted. Disassembly BDP-10A 1. Using a 10 mm wrench, loosen the end cap bolts (4) evenly. 2. Keeping the end cap (2) held in place, remove the four end cap bolts (4). 3.
REMOVAL, INSPECTION AND ASSEMBLY OF THE END CAP AND VALVE PLATE BDP-16A Refer to figure 23. This is normal. Grooving in the plate, or material transfer that is evident when the surface is checked by dragging a fingernail across it, would be cause for replacement of the valve plate. 3. Inspect and replace alignment pins (26) if bent or distorted. Disassembly BDP-16A 1. Using any combination of two, 9/16” wrenches or 9/16” socket and rachet drive, loosen the end cap bolts (58) evenly. 4.
REMOVAL, INSPECTION AND ASSEMBLY OF THE END CAP AND VALVE PLATE BDP-21L Refer to figure 24. This is normal. Grooving in the plate, or material transfer that is evident when the surface is checked by dragging a fingernail across it, would be cause for replacement of the valve plate. 3. Inspect and replace alignment pins (26) if bent or distorted. Disassembly BDP-21L 1. Using any combination of two, 9/16” wrenches or 9/16” socket and rachet drive, loosen the end cap bolts (58) evenly. 4.
REMOVAL, INSPECTION AND ASSEMBLY OF THE CYLINDER BLOCK BDP-10A Refer to Figure 25. Assembly BDP-10A 1. Install piston seats into the end of the pistons. 2. Install springs into the pistons. Disassembly BDP-10A 3. Install one at a time, pistons, springs and seats as one assembly into the cylinder block. 1. Tilt the BDP on its side, drain remaining oil. Lift out the cylinder block assembly (25). 4.
REMOVAL, INSPECTION AND ASSEMBLY OF THE CYLINDER BLOCK BDP-16A/21L Refer to Figure 26. Assembly BDP-16A/21L 1. Install piston seats into the end of the pistons. 2. Install springs into the pistons. Disassembly BDP-16A/21L 3. Install one at a time, pistons, springs and seats as one assembly into the cylinder block. 1. Tilt the BDP on its side, drain remaining oil. Lift out the cylinder block assembly (38). 4.
REMOVAL, INSPECTION AND ASSEMBLY OF BLOCKSPRING, THRUST WASHER, AND THRUST BEARING, BDP-10A/16A Refer to Figure 27. REMOVAL, INSPECTION AND ASSEMBLY OF THRUST BEARING, BDP-21L Refer to Figure 28. Disassembly BDP-21L Disassembly BDP-10A/16A 1. Remove the block spring (29/20). 2. Remove the thrust washer (30/19). 3. Remove the thrust bearing and race (34/17). Inspection BDP-10A/16A 1. Inspect and replace the block spring (29/20) and thrust washer (30/19) if they are distorted or broken. 2.
REMOVAL, INSPECTION OF SWASHPLATE, INSPECTION OF CRADLE BEARINGS BDP-10A/16A REMOVAL, INSPECTION AND ASSEMBLY OF SWASHPLATE, AND CRADLE BEARINGS, BDP-21L Refer to Figure 29. Refer to Figure 30. Disassembly BDP-10A/16A Disassembly BDP-21L 1. Remove the swashplate(32/31). 1. Remove the swashplate (31). Inspection BDP-10A/16A Inspection BDP-21L 1. Inspect the running surface of the bearing pocket for damage (32/31), nicks or unusual wear patterns.
REMOVAL, INSPECTION AND ASSEMBLY OF INPUT SHAFT BDP10A Note: If trunnion arm is to be removed, delay reassembly of input shaft assembly. Refer to Figure 31. Assembly BDP-10A Disassembly BDP-10A Note: 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 clean petroleum jelly prior to assembly. Also, protect the inner diameter of seals by covering the shaft with plastic wrap. 1.
REMOVAL, INSPECTION AND ASSEMBLY OF INPUT SHAFT, BDP-16A/21L 4. Inspect and replace the retaining ring (3) if it is bent or broken. Note: If trunnion arm is to be removed, delay reassembly of input shaft assembly. Refer to Figure 32. Disassembly BDP-16A/21L 5. Inspect and replace the thrust spring (20) and thrust washer (19) if they are distorted or broken. 1. Remove the retaining ring (3). Assembly BDP-16A/21L 2. Remove the lip seal (6).
REMOVAL, INSPECTION TRUNNION ARM BDP-10A/16A REMOVAL, INSPECTION TRUNNION ARM BDP-21L Refer to Figure 33. Refer to Figure 34. Disassembly BDP-10A/16A Disassembly BDP-21L 1. Remove and discard the trunnion seal retainer and seal (49/12). 1. Remove trunnion seal retainer (10) and seal (12). 2. Remove the slot guide (38/14). 2. Remove slot guide (14). 3. Remove the trunnion arm (37/13). 3. Remove trunnion arm (13). Inspection BDP-10A/16A Inspection BDP-21L 1.
NOTES BDP-10A/16A/21L 34
Figure 35. BDP-21L 35 BDP-10A/16A/21L BDP-21L 85 - Overhaul Seal Kit BRACKETS INDICATE ITEMS INCLUDED IN KITS. ITEMS IN KITS CANNOT BE ORDERED SEPARATELY.
ITEMS LIST BDP-21L Part numbers are not provided in this manual. See microfiche or CD for part numbers. No. Description No.
99 - OVERHAUL SEAL KIT BDP-16A Figure 36.
ITEMS LIST BDP-16A Part numbers are not provided in this manual. See microfiche or CD for part numbers. No. Description No.
Figure 37. BDP-10A 39 BDP-10A/16A/21L 10 54 66 75 56 45 59 7 10 69 90 6 59 OBSOLETE 10 7 OR (PORT "A" SIDE) 42A 8 4X 4 42A (PORT "A" SIDE) OR BOXES INDICATE ITEMS INCLUDED IN KITS. ITEMS IN KITS CANNOT BE ORDERED SEPARATELY.
ITEMS LIST BDP-10A Part numbers are not provided in this manual. See microfiche or parts manual for part numbers. No.
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 fluid to bypass the motor or pump. Also referred to occasionally as the freewheel valve or dump valve.
Hydrostatic Transaxle: A multicomponent assembly including a gear case and a hydrostatic transmission. 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 Hydrostatic Transaxle (IHT): 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.
NOTES 43 BDP-10A/16A/21L
NOTES BDP-10A/16A/21L 44
© 2003 HYDRO-GEAR Printed in U.S.A.
