Challenger 35, Challenger 45 and Challenger 55 Agricultural Tractors Implement, Steering and Brake Hydraulic Systems Caterpillar

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Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.

Test Preparation

Prior to mounting the steering control on the test bench, manually test the input shaft of the steering control. Make sure that the nominal travel of the input shaft is 340 degrees.

The input shaft must rotate freely and the input shaft must return to the centered position when the input torque is removed. The maximum torque that causes the input shaft to contact the mechanical stops should not exceed 4 N·m (3 lb ft).

Determine the Position for Zero Input

The steering control should be mounted onto a test bench for this test.

During the test, measure both the angle of the input position and the input torque for each position of the input shaft.

1. Slowly rotate the input shaft from the initial position to 10 ± 1 degrees in the clockwise direction.

   1. Record the angle when the input torque is 0.5 N·m (4.4 lb in).

2. Return the input shaft to the initial position.

3. Slowly rotate the input shaft by 10 ± 1 degrees in the counterclockwise direction.

   1. Record the angle when the input torque is 0.5 N·m (4.4 lb in).

4. Rotate the input shaft clockwise to the initial position.

5. Determine the position for zero input.

   1. The position is the midpoint between the angles that were recorded in Steps 1 and 3.

      Note: The position for zero input is the starting point for plotting the test data for the functional test and the leakage test.

Leakage Test

Illustration 1	g00508946
(AR) Output port for right turn (AL) Output port for left turn (T) Drain port (RP) Port for reduced pressure (P) Supply port (1) Screw (2) Locking nut

For this test, the steering control should be mounted onto a test bench. The oil should be at 27°C (80.6°F).

1. Block outlet ports (AR) and (AL) .

2. Connect port (T) to a measuring device for flow.

3. Install a 0 to 1000 kPa (0 to 145 psi) pressure gauge into port (RP) .

   1. Connect the 5P-3501 Adapter to the 8T-0854 Pressure Gauge .

   2. Remove the plug.

   3. Install the adapter and the pressure gauge into port (RP) .

4. Apply a flow of 10 ± 1 L/min (2.64 ± 0.26 US gpm) at 2500 ± 100 kPa (362 ± 14 psi) to port (P) .

5. Adjust the plunger in order to achieve 390 ± 20 kPa (56.6 ± 2.9 psi) at port (RP) .

   1. Loosen locking nut (2) .

   2. Rotate screw (1) .

   3. Tighten locking nut (2) .

6. Rotate the input shaft in the clockwise direction from 5 degrees to 165 degrees from the position for zero input.

   1. There should be no more than 1.1 L/min (0.291 US gpm) of leakage from the drain port during this condition.

7. Rotate the input shaft in the counterclockwise direction from 5 degrees to 165 degrees from the position for zero input.

   1. There should be no more than 1.1 L/min (0.291 US gpm) of leakage from the drain port during this condition.

8. Rotate the input shaft from 5 degrees in the clockwise direction to 5 degrees in the counterclockwise direction.

   1. The leakage should be no more than 1 L/min (0.264 US gpm) during this condition.

9. If the leakage from port (T) is too high, perform the functional test. Refer to "Functional Test". Then, repeat the leakage test.

Functional Test

Illustration 2	g00508946
(AR) Output port for right turn (AL) Output port for left turn (T) Drain port (RP) Port for reduced pressure (P) Supply port (1) Screw (2) Locking nut

For this test, the steering control should be mounted onto a test bench. The oil should be at 49°C (120°F).

1. Install a 0 to 1000 kPa (0 to 145 psi) pressure gauge into port (RP) .

   1. Connect the 5P-3501 Adapter to the 8T-0854 Pressure Gauge .

   2. Remove the plug.

   3. Install the adapter and the pressure gauge into port (RP) .

2. Install a 0 to 2000 kPa (0 to 290 psi) pressure gauge onto each of ports (AR) and (AL) .

   1. Use two 5P-3501 Adapters to attach the 8T-0849 Pressure Gauges to the ports.

3. Apply a flow of 10 ± 1 L/min (2.64 ± 0.26 US gpm) at 2500 ± 100 kPa (362 ± 14 psi) to port (P) .

4. Purge the air from the steering control.

   1. Rotate the input shaft in the clockwise direction from the position for zero input to 60 degrees.

   2. Open the output line in order to purge the air from the steering control.

   3. Rotate the input shaft in the counterclockwise direction from the position for zero input to 60 degrees.

   4. Open the output line in order to purge the air from the steering control.

5. Adjust the plunger in order to achieve 410 ± 10 kPa (59.5 ± 1.5 psi) at port (RP) .

   1. Loosen locking nut (2) .

   2. Rotate screw (1) .

   3. Tighten locking nut (2) .

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Illustration 3	g00508105

6. Slowly rotate the input shaft in the clockwise direction from the position for zero input to 165 degrees.

   1. Record the pressure at port (AR) for each degree of rotation.

   2. The recorded values must be within three percent of the values that are in Illustration 3.

   3. The pressure at port (AR) must be at least 1400 kPa (203 psi) when the input shaft is at 165 degrees.

7. Slowly rotate the input shaft from 165 degrees in the clockwise direction to the position for zero input.

   1. Record the pressure at port (AR) for each degree of rotation.

   2. The recorded values must be within three percent of the values in Illustration 3.

   3. Note the values from 60 degrees to the position for zero input. These values must be no more than 35 kPa (5.08 psi) different from the values that were recorded for the same range in Step 6.

8. Slowly rotate the input shaft in the counterclockwise direction from the position for zero input to 165 degrees.

   1. Record the pressure at port (AL) for each degree of rotation.

   2. The recorded values must be within three percent of the values that are in Illustration 3.

   3. The pressure at port (AL) must be at least 1400 kPa (203 psi) when the input shaft is at 165 degrees.

9. Slowly rotate the input shaft from 165 degrees in the counterclockwise direction to the position for zero input.

   1. Record the pressure at port (AL) for each degree of rotation.

   2. The recorded values must be within three percent of the values in Illustration 3.

   3. Note the values from 60 degrees to the position for zero input. These values must be no more than 35 kPa (5.08 psi) different from the values that were recorded for the same range in Step 8.