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Personal injury or death can result if two persons are not used in the following procedure. |
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| NOTICE |
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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 Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates. |
Machine Preparation
Prepare the machine for testing by completing the procedure that is specified in Machine Systems, "Troubleshooting" for the machine that is being serviced.
Test Procedure
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| Illustration 1 | g01588433 |
View of the Front Axle Housing (1) Air purge screws | |
The four air purge screws for the service brakes are located on the top of the corresponding axle housing.
Note: Perform this procedure for one service brake at a time.
- Check the hydraulic tank oil level. Make sure that the correct oil level in the hydraulic oil tank is maintained throughout the air removal procedure.
- Start the engine. Allow the oil pressure to increase to the cutout pressure.
- Fasten one end of a transparent tube that is 6.4 mm (.25 inch) in diameter to the air purge screw. Put the other end of the tube into a suitable container for collecting the hydraulic oil. The tube may also be routed back to the hydraulic oil tank. Loosen the air purge screw (1) .
- The operator should slowly depress the brake pedal. Hold the brake pedal in this position throughout Step 5.
- As the hydraulic oil flows through the tube, look for air bubbles in the oil. Allow the oil to flow into the container until no air bubbles are visible. Then, tighten the air purge screw (1). Release the brake pedal.
- Perform this procedure for each of the other service brakes. Make sure that all of the air purge screws are tightened.
- Fill the hydraulic tank, if necessary.
Note: If the brake pedal is spongy during the first hours of operation, perform this procedure again.