R2900G Load Haul Dump Hydraulic System Caterpillar

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Personal injury or death can result from sudden movement of the lift or tilt cylinders. Sudden movement up or down, can cause the clearance above your head to change rapidly. Do not stand under the lift arms when testing and adjusting the lift cylinders. Do not stand under the bucket when testing or adjusting the tilt cylinder.

This test will check the drift rate of the lift cylinders. The drift rates will change according to many conditions (hydraulic oil temperature, load in the bucket, etc). The values in the table are for an empty bucket.

Lift Cylinder

Note: Prior to the lift cylinder drift check, the machine should be at operating temperature.

1. Move the machine to an open area so that the lift arms can be fully raised.

2. Engage the parking brake. Stop the engine.

3. Install the steering frame lock.

4. If the machine is equipped with ride control, move the ride control switch to the OFF position.

5. Shift the transmission to the NEUTRAL position.

6. Start the engine. Warm the hydraulic oil to normal operating temperature.

7. Extend and retract the lift cylinders five times. This ensures that there is warm oil in the lift cylinders.

8. Raise the bucket to the maximum height off the ground. Move the joystick control lever to the HOLD position.

9. Turn the engine start switch to the OFF position.

Note: The operator station door must be in the OPEN position during Step 10 and Step 11.

10. Record the position of a lift cylinder rod.

11. Measure the distance that the lift cylinder rod has moved.

    Reference: Refer to Table 1 for the maximum drift that is allowed for the time and the temperature range for the hydraulic oil.

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    Table 1

    Oil Temperature	Maximum Drift	Time (Minutes)
    38 ± 3°C (100 ± 5°F)	13 mm (0.51 inch)	5
    49° ± 3°C (120° ± 5°F)	13 mm (0.51 inch)	2.7
    66° ± 3°C (150° ± 5°F)	13 mm (0.51 inch)	1.7

12. Start the engine. Lower the bucket to the ground. Turn the key start switch to the OFF position. Proceed to "Tilt Cylinder" in order to test drift for the tilt cylinder.

Tilt Cylinder

Note: Prior to the tilt cylinder drift check, the machine should be at operating temperature.

1. Move the machine to an open area so that the lift arms can be fully raised.

2. Engage the parking brake. Stop the engine.

3. Install the steering frame lock.

4. Shift the transmission to the NEUTRAL position.

5. Start the engine. Warm the hydraulic oil to normal operating temperature.

6. Raise the lift arms so the bucket will clear the ground in the full DUMP position. Extend and retract the tilt cylinder five times. This ensures that there is warm oil in the tilt cylinder.

7. Position the bucket so that the bottom of the bucket is parallel to the ground. Move the joystick control lever to the HOLD position.

8. Turn the key start switch to the OFF position.

Note: The operator station door must be in the OPEN position during Step 9 and Step 10.

9. Record the position of the tilt cylinder rod.

10. Measure the distance that the tilt cylinder rod has moved.

    Reference: Refer to the Table 2 for the maximum drift that is allowed for the time and the temperature range for the hydraulic oil.

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    Table 2

    Oil Temperature	Maximum Drift	Time (Minutes)
    38 ± 3°C (100 ± 5°F)	19 mm (0.75 inch)	5
    49° ± 3°C (120° ± 5°F)	19 mm (0.75 inch)	2.7
    66° ± 3°C (150° ± 5°F)	19 mm (0.75 inch)	1.7

11. Start the engine. Lower the bucket to the ground. Turn the engine start switch to the OFF position.

12. Place the steering frame lock in the stored position.