CORE AS-RADIATOR 4175127 - Caterpillar

Hydraulic Motor Leakage Tests
A certain amount of internal leakage is needed for lubrication and cooling in the hydraulic motors. Leakage above the allowed value will reduce the rotation speed of the motor and prevent the motor from developing maximum torque. All the moving components of the hydraulic motors require lubrication. The components are sealed either by the use of seals or by matching surfaces which have been machined to high precision tolerances and finish.Internal leakage in a hydraulic motor occurs when oil passes from the supply line into the motor case where it returns to tank.
Refer to the on the first page of Troubleshooting.
When doing a hydraulic leakage test, the brake release hoses must be disconnected from motors. This allows the brakes to remain engaged during the test.The two types of internal leakage found in a hydraulic motor are piston and distributor leakage. Piston leakage is when oil passes from the supply line into the motor case, where it returns to the tank. Distributor leakage is oil leakage from the supply line into the return line of the loop circuit. Leakage can also be from the supply line into the motor case.Distributor And Piston Leakage Test
Drum Area
(1) Propel motor. (2) Brake release line.1. Disconnect brake release hose (2) from both front propel motors (1). Disconnect the brake release lines from both of the rear propel motors. Plug the ends of the hoses and the brake release port of each propel motor. The test described here is for the front propel motors. To test the rear propel motors, perform the test using the rear propel motors and rear motor return lines. This procedure should be performed on one motor at a time.
Caution must used when positioning wooden wedges under drum, to prevent machine movement at full throttle. To prevent possible personal injury, an operator should remain seated in the operators station while preforming this adjustment procedure.
2. Place wooden wedges under both sides of the drum.3. Disconnect the return line hose from the motor to be tested and install a plug in the end of the hose. Connect one end of a separate hose to the return line fitting on the propel motor being tested. Place the other end of this hose in a 19 liter (5 U.S. gal) graduated container.
To prevent overheating of the hydraulic oil and damage to the propel system components, do not run each test longer than 30 seconds.
4. Start and run the engine at 2200 rpm. Move the speed limiter valve to the maximum travel speed position. Pull the stop control upwards.5. Slowly move the propel control lever fully forward. When the lever is fully forward move the hose from the first graduated container to a second 19 liter (5 U.S. gal) graduated container. Allow the oil to run into the container for a period of 30 seconds. To obtain the leakage value in liter/min, multiply the value that is obtained during the 30 second test period by two. The value should be less than