143H and 163H Motor Graders All Wheel Drive Caterpillar

This is the procedure for inspecting the displacement spool valve. The displacement spool valve is located in the distribution valve. The distribution valve is located in the all wheel drive piston motor. The displacement spool valve causes the displacement of the all wheel drive piston motor to change. The displacement spool valve receives a displacement signal from the all wheel drive control valve.System Operation

Reference: Refer to Troubleshooting, "Piston Motor (All Wheel Drive)".

Test Step 1. Perform the following test: Machine Preparation for Troubleshooting

Results:

• OK - Proceed to test step 2.

Test Step 2. Perform the following test: Hydraulic Pressure - Release

Results:

• OK - Proceed to test step 3.

Test Step 3.

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NOTICE
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

1. Remove the housing from the all wheel drive piston motor. Remove the spring and the displacement spool valve from the distribution valve.

2. Inspect the spring and the displacement spool valve for wear or damage.

Reference: Refer to Troubleshooting, "Piston Motor (All Wheel Drive)".System Operation

Reference: Refer to Troubleshooting, "Piston Motor (All Wheel Drive)".How...

Reference: Refer to Troubleshooting, "All Wheel Drive Motors".

Expected Result:

The spring and the displacement spool valve are in good condition.

Results:

• Yes - Proceed to test step 4.

• No - Proceed to test step 5.

Test Step 4.

1. Clean all parts prior to installation in the all wheel drive piston motor.

2. Install the displacement spool valve and the spring to the distribution valve.

3. Install the housing to the all wheel drive piston motor.

Reference: Refer to Troubleshooting, "All Wheel Drive Motors".

Expected Result:

The displacement spool valve and the springs have been installed in the all wheel drive piston motor.

Results:

• Continue - Proceed to test step 6.

Test Step 5.

1. Replace the worn parts or the damaged parts. Use a new Caterpillar part for replacement.

2. Clean all parts prior to installation in the all wheel drive piston motor. Install the displacement spool valve and the spring to the distribution valve.

3. Install the housing to the all wheel drive piston motor.

Reference: Refer to Troubleshooting, "All Wheel Drive Motors".Specifications

Reference: Refer to Troubleshooting, "Wheel Drive".Parts

Reference: Refer to Troubleshooting, "114-6577 HOUSING GP-MOTOR PIN 5AK1-UP. PART OF 104-3636, 104-3637 MOTOR GP-PISTON".

Expected Result:

The worn parts or the damaged parts have been replaced.

Results:

• Continue - Proceed to test step 7.

Test Step 6.

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NOTICE
This procedure must be completed before operating the all wheel drive system. Failure to do so can result in damage to the front motor pistons due to lack of lubrication.

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NOTICE
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

1. Fill the all wheel drive piston motor with hydraulic oil.

Reference: Refer to Troubleshooting, "Wheel Drive - Lubricate".Specifications

Reference: Refer to Troubleshooting, "Wheel Drive".

Expected Result:

The all wheel drive piston motor has been filled with hydraulic oil.

Results:

• OK - Stop.

Test Step 7.

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NOTICE
This procedure must be completed before operating the all wheel drive system. Failure to do so can result in damage to the front motor pistons due to lack of lubrication.

Show/hide table

NOTICE
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

1. Fill the all wheel drive piston motor with hydraulic oil.

Reference: Refer to Troubleshooting, "Wheel Drive - Lubricate".

Expected Result:

The all wheel drive piston motor has been filled with hydraulic oil.

Results:

• Repair Complete - Stop.