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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin. |
| 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. |
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| Illustration 1 | g03142304 |
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(6) Service brake control valve
(8) Parking brake control valve | |
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| Illustration 2 | g03885104 |
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(G1) Lift rod end pressure
(G2) Parking brake pressure (G3) Left valve supply pressure (G4) Tilt head end pressure (G5) Lift head end pressure (G6) Tilt rod end pressure (G7) Right valve supply pressure | |
| Specifications | ||||
| Accumulator Pressure with Engine Running | Accumulator Pressure at which the Parking Brake Engages | |||
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The following procedure describes the system pressure test for the service brakes.
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| Illustration 3 | g02726620 |
| Required Tools | ||||
| Tool | Item | Qty | Part No | Description |
| B | B1 | 1 | 8T-0855 | Pressure Gauge |
| B2 | 1 | 6V-3989 | Fitting | |
| B3 | 2 | 6V-4143 | Quick Connect Coupler | |
| B4 | 1 | 177-7862 | Hose As | |
- Be sure that the machine is in an open area and that the area is clear of personnel.
- Place the steering frame lock in the stored position.
- Position the machine on a dry, hard, level surface.
- Attach a hydraulic hose and a
0 to 15850 kPa (0 to 2300 psi) pressure gauge to pressure port (A2). - Start the engine and allow the accumulator oil pressure to increase to the cut-in pressure.
Note: When the engine is running, the accumulator oil pressure will continue to increase to approximately
13790 ± 345 kPa (2000 ± 50 psi) . - Ensure the parking brake control switch is in the OFF position and stop the engine.
- Depress the brake pedal repeatedly until the parking brake warning comes on showing the parking brake has been applied.
- Look at the reading on the pressure gauge. The correct hydraulic oil pressure that automatically engages the parking brake should be below
6900 kPa (1000 psi) . - If the reading on the pressure gauge is not correct, the operation of the parking brake control valve is not correct.
Inspect the parking brake control valve for parts that are worn or damaged. If any parts are worn or damaged, replace the parking brake control valve.
- Remove the test equipment.