Machine Preparation
- Move the machine to a smooth horizontal location. Move away from working machines and personnel. Lower the attachments to the ground.
- Allow only one operator on the machine. Keep all personnel away from the machine or in the view of the operator.
- Engage the parking brake.
Performance Test
Stall Test
The amount of oil flow that is produced by a pump will increase with the speed of the pump. First verify that the pump is operating at the rated speed in order to test the performance of a pump. Perform the torque converter stall test in order to verify that a pump is operating at rated speed.
- Shift the transmission to the NEUTRAL position.
- Start the engine. Warm the transmission oil to normal operating temperature of approximately 74° to 85°C (165° to 185°F).
- Lower the bucket and/or work tools to the ground.
- Fully depress the right side service brake pedal. Hold the brake pedal in the depressed position for the duration of the test.
- Release the parking brake.
- Shift the transmission direction and speed control to THIRD SPEED FORWARD position and fully depress the accelerator pedal.
| NOTICE |
|---|
To make sure that the transmission oil does not overheat, do not keep the torque converter in a stall condition for more than 30 seconds. After the torque converter stall test, reduce engine speed to low idle, move the transmission control to neutral and increase the engine speed to approximately 1500 rpm to cool the oil. |
- Allow the engine rpm to stabilize. Then, observe the tachometer. The correct torque converter stall speed is 2150 ± 65 rpm.
- Reduce the engine speed to low idle. Shift the transmission to the NEUTRAL position.
- Apply the parking brake and release the right side service brake pedal. If necessary, open the ball valve by turning the lever to OPEN position (B) .
Allow the engine coolant and the transmission oil to cool. Wait for at least two minutes between tests in order to allow the transmission oil to cool.
If the torque converter stall speed is more than 2215 rpm, the engine power output could be too high or the torque converter could have excess slippage.
If the torque converter stall speed is less than 2085 rpm, the engine may not be developing full power. There may be a parasitic load on the engine.
Note: The stall speed should be corrected before the performance of the implement pump can be properly tested.
Reference: For more information on the torque converter stall test, refer to the Service Manual module Testing and Adjusting, "Torque Converter Stall and Implement Pump Double Stall - Test" for the machine that is being serviced.
Implement Cycle Time
The speed of the implements is affected by the amount of oil flow that is produced by the implement pump. Check the implement cycle times in order to determine if there may be a problem with the implement pump.
- Perform the machine preparation for testing.
- Warm the hydraulic oil to normal operating temperature of approximately 65° ± 3°C (150° ± 5°F).
- Begin the test for the lift cycle time with the bucket flat on the ground.
- Increase the engine speed to high idle.
- Pull the lift control lever back to the full RAISE position. Measure the lift cycle time. Record the lift cycle time.
- Raise the boom to the full raised position.
- Tilt the bucket to the full TILT BACK position.
- Move the control lever to the full DUMP position. Measure the tilt cycle time. Record the tilt cycle time.
- Lower the boom and place the bucket flat on the ground.
- Reduce engine speed to low idle.
- Stop the engine.
| Cycle Time for Lift Cylinders | Speed |
| RAISE from ground to lift kickouts (empty bucket) | 7.0 ± 0.4 seconds |
Note: In order to perform the cycle time tests for the tilt circuit, the lift arms must be raised to the maximum height.
| Cycle Time for Tilt Cylinder | Speed |
| DUMP from full tilt back position to full dump position (empty bucket at maximum height) | 2.8 ± 0.3 seconds |
Compare the test results with the cycle times that are listed in Tables 1 and 2. The implement pump should be working properly if the implement cycle times match the cycle times that are listed in Tables 1 and 2.
If the cycle times are not correct for both the lift and tilt functions one of the following conditions are present:
- The main relief valve pressure setting is not within the specifications.
- The pump is not upstroking.
- The pump may have excessive wear.
The main relief pressure should be measured. If the main relief pressure is low, the cycle times should be retested after the main relief pressure has been corrected.
Reference: For more information on testing and adjusting the main relief valve, refer to the Service Manual module Testing and Adjusting, "Relief Valve (Main) - Test and Adjust" for the machine that is being serviced.
If the cycle time is slow for only one of the implement circuits, the circuit with slow cycle time should be tested for one of the following conditions:
- Low relief valve setting
- Leak in the circuit
- Control spool that is not shifting fully
Reference: For more information on troubleshooting the hydraulic system, refer to the Service Manual module Testing and Adjusting, "Hydraulic System Troubleshooting" for the machine that is being serviced.