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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine. |
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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand. |
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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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates. |
Introduction
The following procedure is designed to check the pressure for the front brake manifold. The pressure comes from a pressure reducing valve on the pilot/differential manifold that is located under the cab. This pressure is used to supply all the functions that are on the manifold. These functions include the service brakes, the front differential lock, and the parking brake.
Note: The pressure reducing valve also supply to the rear differential lock.
Refer to the Operation and Maintenance Manual and Disassembly and Assembly manual for weights and procedures to remove the cab.
Note: Use validated gauges for this test
Note: Warm up the system to a minimum of 54° C (130 ° F)
Required Tools
| Required Tools | |
| Item | Description |
| AA | 34475 kPa (5000 psi) pressure gauge |
Machine Preparation
- Move the machine to level ground. Install the frame lock.
- Stop the engine. Parking brake will engage.
- Turn the key switch to the ON position. Do not start the engine.
- Close the cab door. Press the arming button on the keypad. Depress all the pedals. Move the joysticks.
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| Illustration 1 | g02641456 |
- Turn the key switch to the OFF position.
- Raise the cab to gain access to the brake accumulator. Refer to the Operation and Maintenance Manual for instructions to raise the cab.
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| Illustration 2 | g02654018 |
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| Illustration 3 | g02652636 |
Location of the accumulator | |
- Open the brake accumulator drain valve. This action will drain the oil out of the accumulator. Close the brake accumulator drain valve.
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| Illustration 4 | g02657699 |
Location of the brake accumulator drain valve on the rear manifold. | |
Test Procedure Front Brake Manifold
- The test procedure requires two people to perform the test.
- Remove the cover from the front frame.
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| Illustration 5 | g02639656 |
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| Illustration 6 | g02705978 |
Location of the Front Manifold | |
- Remove the protective cap from pressure tap (1) in order to test the oil pressure of the front brake. Connect the 34475 kPa (5000 psi) pressure gauge (AA) .
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| Illustration 7 | g02668779 |
Location of Pressure Tap (1) Pressure tap for the front brake manifold. | |
Note: The pressure tap for the front brake is located on the front manifold.
- Look at the pressure gauge. Before the engine is started, the oil pressure must be 0 kPa (0 psi).
- Close the cab door.
- Start the engine and allow the hydraulic oil to 54° C (130 ° F) normal operating pressure. Press arming button (2) to activate the machine functions.
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| Illustration 8 | g02639801 |
- The front brake manifold pressure should be at 11032 kPa (1600 psi).
- If the front brake manifold pressure is not correct, follow the procedure to adjust the pressure reducting valve on the pilot differential manifold. If the pressure is correct, shut off the machine. Remove the pressure gauge. Install the cover.
Adjust Procedure for Pressure Reducing Valve
- Leave the pressure gauge hooked up.
- Tilt the cab to access the pressure reducing valve on the pilot differential manifold.
- Unlock the set screw on pressure reducing valve (3). Turn in to increase pressure, turn out to decrease pressure. Set the pressure to 11032 kPa (1600 psi). Tighten the locknut on pressure reducing valve (3) .
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| Illustration 9 | g02669438 |
(3) Pressure reducing valve | |
- Shut the engine off. Lower the cab. Remove the gauge. Install the cover.