950G Wheel Loader, 962G Wheel Loader and IT62G Integrated Toolcarrier Hydraulic System Caterpillar

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Sudden movement or accidental starting of the machine can cause personal injury or death to persons on or near the machine. To prevent personal injury or death, perform the following: Park the machine on a smooth, level surface. Lower the bucket and/or attachments to the ground and engage the parking brake. Stop the engine and remove the key. Block the wheels and install the steering frame lock.

An initial test for lift cylinder drift should be done before isolating the lift cylinder.

Reference: Testing and Adjusting, SENR1390, "Lift and Tilt Cylinder Drift - Check"

This test will help to determine whether the lift cylinder is causing a drift problem. When the oil port at the end of the lift cylinder is blocked, the lift cylinder should not move during a drift test. If the lift cylinder moves, there is internal leakage in the lift cylinder.

1. Start the engine. Move the transmission direction control switch to the NEUTRAL position.

2. Engage the parking brake.

3. Move the steering frame lock to the locked position.

4. Raise the bucket off the ground approximately 1 m (3.3 ft). Place a support block under the bucket. Lower the bucket onto the support block.

5. Stop the engine.

6. When the engine has stopped, turn the engine start switch key to the ON position. Move the hydraulic control levers to all positions in order to release the pressure in the hydraulic system. Place the lift control lever in the FLOAT position. Place the tilt control lever in the HOLD position.

7. Push in the plunger for the hydraulic tank breaker relief valve in order to relieve the pressure in the hydraulic oil tank. Push down on the plunger until all pressure is released from the hydraulic oil tank.

8. Release all hydraulic pressure before any fitting, any hose, or any component is loosened, tightened, removed, or adjusted.

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Illustration 1	g00298838
Hose Assemblies (Head End)

9. Remove one hose assembly from the manifold. Install a 6V-9511 Face Seal Plug in the hose that connects to the head end of the lift cylinder. Install a 8L-9137 Flared Cap on the manifold.

10. Start the engine. Warm the hydraulic oil to normal operating temperature of approximately 54° to 82°C (129° to 180°F).

11. To check the lift cylinder, raise the bucket to the maximum height and move the control lever to the FLOAT position. Place the hydraulic lever lock in the OFF position.

12. Stop the engine.

13. Turn the engine start key to the ON position. Place the lift control lever in the FLOAT position. Check the distance of rod movement according to the following chart.
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    Table 2

    Approximate Lift Cylinder Drift
    Oil Temperature	Maximum Drift	Time
    38° to 49°C (100° to 121°F)	13.0 mm (.51 inch)	5.0 minutes
    50° to 65°C (122° to 149°F)	13.0 mm (.51 inch)	2.7 minutes
    66°C (150°F) or more	13.0 mm (.51 inch)	1.7 minutes

14. If the amount of cylinder drift is within the specification, this lift cylinder is not causing the drift problem. If there is too much drift, the lift cylinder has an internal leak. Look for a scored cylinder and/or worn piston seals.

15. Start the engine. Lower the bucket to the support block.

16. Place the support block under the bucket. Make sure that the weight of the bucket is on the support block.

17. Stop the engine and release the hydraulic system pressure.

18. When the engine has stopped, move the lift control lever and the tilt control lever in order to relieve the pressure in the hydraulic system.

19. Push in the plunger for the hydraulic tank breaker relief valve in order to relieve the pressure in the hydraulic oil tank. Push down on the plunger until all pressure is released from the hydraulic oil tank.

20. Remove the plug from the hose connection and the cap from the manifold. Reconnect the hose assembly.

21. Repeat Steps 9 through 20 for the other lift cylinder.