PUMP GP-GEAR 1643065 - Caterpillar

Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine.To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
When a hydraulic line is disconnected from the cushion-hitch pump, make sure to keep the disconnected end of the hydraulic line above the level of the cushion-hitch pump. This will prevent hydraulic oil from draining out of the body of the cushion-hitch pump while the engine is not running.
Table 1
Required Tools    
Tool     Part Number     Description     Qty    
A     4C-4892     ORFS Fittings Group     1    Refer to Testing and Adjusting, "Machine Preparation for Troubleshooting".
Illustration 1 g00803861
(1) Pressure line from the outlet of the cushion-hitch pump (2) Cushion-hitch pump (3) Drain line from the cushion-hitch pump (4) Supply line to the cushion-hitch pump (5) Pump control valveSome of the hydraulic oil that is pumped by the cushion-hitch pump (2) is not pumped through the pressure line (1) from the outlet of the cushion-hitch pump (2). The hydraulic oil that is not pumped through pressure line (1) by cushion-hitch pump (2) is called leakage oil.The leakage oil flows into the pump body of cushion-hitch pump (2). The leakage oil lubricates the moving parts of cushion-hitch pump (2). This leakage oil flows into drain line (3) from cushion-hitch pump (2) .The volume of leakage oil increases under either of the following three circumstances:
The rpm of the pump is increased.
The output pressure of the cushion-hitch pump (2) increases.
The components of cushion-hitch pump (2) are worn.If the amount of wear on the components of cushion-hitch pump (2) increases, the volume of leakage oil also increases. The volume of leakage oil that flows through drain line (3) from cushion-hitch pump (2) is one indication of the condition of cushion-hitch pump (2) .If a bench test is performed, the maximum leakage rate for cushion-hitch pump (2) is 4.8 L/min (1.27 US gpm) at 2000 rpm and 16000 350 kPa (2321 51 psi).In order to test a cushion-hitch pump that is mounted to the machine, proceed to step 1.
Make sure that the hydraulic oil tank is filled with hydraulic oil. Start the engine. Operate the scraper bowl until the temperature of the hydraulic oil is 63°C (145°F) to 68°C (155°F).
Depress the push button on the joystick in order to turn off the cushion-hitch. Turn off the engine.
Disconnect the end of drain line (3) from cushion-hitch pump (2). Place the disconnected end of drain line (3) into a