Hydraulic Pump Troubleshooting P & BDP Series Models

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1 Hydraulic Pump Troubleshooting P & BDP Series Models Hydraulic Pump damage can cause traction circuit failures and problematic hydraulic system contamination. Performance problems such as weak traction or no traction response, noisy operation or hydraulic vibration while engaging the traction lever may occur due to a damaged hydraulic pump. If a pump is damaged, the worn/broken pieces may further contaminate the hydraulic traction circuit, causing damage to other hydraulic circuits and components. Troubleshooting Process: Perform an operational check to verify proper traction system operation. Inspect the hydraulic oil for contamination. Black, burnt-smelling oil is an indication of failure to change oil, overloading or overheating. Inspect the pump externally for damage (If under warranty, do not open). Inspect the hydraulic lines for damage Verify all drive linkage is adjusted properly Verify the pump drive belt system is functioning properly Make sure the pump bypass valve is completely closed on each pump Confirm the brake is adjusted properly Perform a flow/pressure test on the suspect pump(s) Document the brand/type of hydraulic oil that was last used. Document hours on the unit and hours since the last hydraulic oil change If under warranty, document all test results and contact your DSM or TST for warranty consideration prior to completing the repair. Pump Inspection Instructions Any unit exhibiting symptoms of pump damage must be properly inspected and tested in order to determine the initial cause of the failure. Perform the following inspection steps in order: 1. Inspect the hydraulic reservoir for metallic contamination. Check for metallic particles in the oil; use a cotton swab or a magnet to check the bottom of the hydraulic reservoir for debris. Contamination in the reservoir indicates a catastrophic failure has occurred and additional flushing steps will be required. Note: Air in the system may cause symptoms similar to a damaged motor or pump. Leaking fittings, missing or damaged o rings, leaking hoses, clogged filter and low oil level in the reservoir may allow air in the system resulting in system cavitation. Seal any leaks and re check for proper operation.

2 2. Verify each pump condition by looking for external leaks around pump and check all hoses for leaks, kinking or damage. Perform a hydraulic flow test to check pump flow and pressure is necessary to determine if damage has occurred. 3. If the unit is under warranty contact your DSM or TST representative for test results that justify a warranty approval (Do not disassemble the pump under warranty). If the unit is out of warranty, disassemble and inspect the pump for internal damage. Troubleshooting Guide PUMP NOISY / WHINE Cavitation Purge trapped air from system; Replace dirty filter; check for air leak on the suction side of the pump (check all hoses and clamps); wash strainers in solvent compatible with system fluid; clean clogged inlet line; clean or replace reservoir breather vent; change system fluid; fluid may be too cold; overhaul or replace pump; Air in fluid Purge air from system; tighten leaking connections; fill reservoir to proper level (with rare exception all return lines should be below fluid level in reservoir); replace pump shaft seal (and shaft if worn at seal journal). Pump worn or damaged PUMP OVERHEATED (DISCOLORATION HARD RUBBER SEALS) Cavitation Replace dirty filters; wash strainers in solvent compatible with system fluid; clean clogged inlet line; clean or replace reservoir breather vent; change system fluid; overhaul or replace pump; fluid may be too cold. Air in fluid Tighten leaking connections; fill reservoir to proper level (with rare exception all return lines should be below fluid level in reservoir); purge air from system; replace pump shaft seal (and shaft if worn at seal journal). Relief or valve sticking or set too high Install pressure gauge and check pressures; repair/replace parts as needed.

3 Excessive load Check condition of seals and bearings; locate and correct mechanical binding; check for work load in excess of circuit design Worn or damaged pump Bypass valve not closed Close bypass valve or check for bypass valve for leakage. Inspect/clean bypass valve tip and bypass valve seat in pump. Fluid dirty or incorrect fluid Change fluid per operator manual recommendations and replace filer; fill reservoir to proper level. Faulty fluid cooling system Clean pump of all debris and check cooling fan for damage. Damaged or leaking seal/gaskets Replaced seals and gaskets PUMP HAS LOW / NO FLOW Pump not receiving fluid Pump gerotor installed 180 degrees off. Directional control set in wrong position Adjust control linkage per operator/service manual. Damaged pump Improperly assembled pump Bypass valve partially open Close bypass valve or check bypass valve for leakage. CONTROLS ARE TOUCHY/JERKEY Pressure relief spring/detent assembly blocked Check pressure relief spring/detent assembly; may be blocked with debris.

4 Tank Vent Plugged The tank vent may be gummed up with debris. A closed loop system must be vented at the tank cap. Clean vent of debris. Control Levers and linkage adjustment Adjust or replaced damaged or worn control lever and linkage components.

5 Flow Test Procedures P Series and BDP 10A & BDP 21L INSTALLATION AND TESTING PROCEDURES: 1. Disconnect the system hoses at the wheel motor, or system hoses from the pump and connect the Flow Test Kit. (Special care should be taken to prevent contamination debris from entering pump or wheel motor system ports). Note: Using the Bi Directional Flow Test Kit, determination of directional flow is not necessary. The flow meter may be connected in either direction into the forward and reverse high pressure system lines. CAUTION: Ensure all fittings and hoses are attached securely. This test is being completed on the vehicle s high pressure system lines. Failure to perform this properly could result in bodily injury. TESTING PROCEDURES: 1. Raise the drive tires off the ground. Block the remaining tires on the ground to prevent accidental vehicle movement. 2. Open the restriction valve all the way on the flow tester. 3. Make certain all external pump directional control stops are removed or backed off on the vehicle linkage to obtain full pump directional control arm travel.

6 4. Start the engine and engage the drive pulley if necessary. 5. Bring the engine to test operating speed. Maximum RPM Pump Type 3600 PC, PL, PE, PK, PJ, BDP10A 3400 PR 2800 PW, BDP21L CAUTION: Damage to the flow meter and/or re calibration may result from testing the PW or BDP 21L at input speeds that exceed 2800 rpm. 6. Move the motion control lever on the vehicle for the pump being tested to full forward position. (It may be necessary to lock the control arm into full forward position to prevent false readings). 7. Operate without any load for approximately 30 seconds to 1 minute; this allows the system oil temperature to rise. Note: Raising the system oil temperature will make a difference in the readings you receive. To complete this test accurately, the oil temperature must be near system operating temperatures. Suggested temperature range F ( C) 8. Tighten the restriction valve on the flow meter until you read 300 psi (21 bar). On the PW or BDP 21L, tighten the restriction valve until you read 500 psi (34 bar), Record the flow reading from the Bi Directional Flow Meter.

7 9. Increase the pressure to 1100 PSI (76 bar) for all models. Record the flow reading from the Bi Directional Flow Meter. 10. The acceptable gpm flow droop or (difference) is: Pump Type Gallons Per Minute PC 1.0 gpm (3.7l/min) PG, PL, PE, BDP 10A, BDP 10L 1.5 gpm (5.6l/min) PJ, PK, BDP 21L 2.0 gpm (7.6l/min) PR, PW 2.5 gpm (9.4l/min) If the difference exceeds these values the pump is not be operating efficiently and should be repaired or replaced.