966G Series II Wheel Loader and 972G Series II Wheel Loader 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 work tool to the ground and engage the parking brake. Stop the engine and remove the key. Block the wheels and install the steering frame lock.

The implement cycle time can be checked in order to verify a complaint about slow implement speed. This test will also help to determine whether all functions are slow or only one function is slow.

Note: For all cycle time tests, the work tool must be empty.

Machine Preparation

1. Perform the torque converter stall test in order to verify that the engine is developing adequate power.

   For more information about performing the torque converter stall test, refer to the Service Manual module Troubleshooting and Testing and Adjusting, "Torque Converter Stall and Implement Pump Double Stall - Test" for the machine that is being serviced.

2. Move the machine to an open area so that the work tool can be fully raised.

3. Shift the transmission to neutral.

4. Warm the hydraulic oil to normal operating temperature. The hydraulic oil must be at a temperature of 65 ± 3°C (150 ± 5°F) in order to obtain accurate results.

Cycle Time Check

RAISE

1. Move the work tool to the TILT BACK position.

2. Lower the work tool completely.

3. Increase the engine RPM to high idle.

4. Move the lift control lever to the RAISE position. Hold the lift control lever in this position until the lift cylinder reaches the end of travel. Record the amount of time that is required for the work tool to travel from the ground to the full RAISE position.

   Refer to Table 1 for the correct cycle time for the machine that is being serviced.

LOWER

1. Position the work tool so that the work tool is flat on the ground.

2. Raise the work tool to the maximum height.

3. Increase the engine RPM to high idle.

4. Move the lift control lever to the full LOWER DETENT position.

   Note: Ensure that the lift control lever is not in the FLOAT position.

   Record the time from the full LIFT position to the ground.

   Refer to Table 1 for the correct cycle time for the machine that is being serviced.

DUMP

1. Position the lift linkage at the midpoint of travel. Tilt back the work tool as far as possible.

2. Increase the engine RPM to high idle.

3. Move the tilt control lever to the full DUMP position. Hold the tilt control lever in this position until the work tool is at the full DUMP position. Record the time to the full DUMP position.

   Refer to Table 1 for the correct cycle time for the machine that is being serviced.

TILT BACK

1. Position the lift linkage at the midpoint of travel.

2. Position the work tool in the full dump position.

3. Increase the engine RPM to high idle.

4. Move the tilt control lever to the full TILT BACK position. Hold the tilt control lever in this position until the work tool is against the stop. Record the time from the level position to the full TILT BACK position.

   Refer to Table 1 for the correct cycle time for the machine that is being serviced.