| Required Tools | |
| Part Number | Description |
| 1U-5481 | Pressure Gauge Group |
 |
Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak. |
 |
|
Personal injury or death can result if two persons are not used in the following procedure. |
|
| 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. |
Machine Preparation
- Stop the engine. Place the transmission direction selector in the NEUTRAL position.
- Engage the parking brake.
- Depress the brake pedal repeatedly in order to release all oil pressure from the brake circuit.
- Remove the protective cap from test port (1) in order to test the oil pressure of the rear service brakes. Install a 0 to 15850 kPa (0 to 2300 psi) pressure gauge.
 | |
| Illustration 1 | g00293357 |
Brake Control Valve (1) Test port for the rear service brakes. (2) Test port for the front service brakes. | |
Testing Procedure
- Look at the pressure gauge. Before starting the engine, the oil pressure must be at the pressure of the hydraulic oil tank.
- Start the engine and allow the hydraulic oil to reach normal operating temperature and normal operating pressure.
- Hold down the brake pedal and look at the pressure gauge. The brake pressure should be at 6895 ± 345 kPa (1000 ± 50 psi).
- If the brake pressure is not in the correct range but the brake accumulator charging valve is functioning correctly, replace the brake control valve.
- Repeat this procedure at test port (2) in order to test the oil pressure of the front service brakes.
Note: The pressure from the upper brake port should be approximately 207 kPa (30 psi) higher than the pressure from the lower brake port.