| Required Tools | |||
| Tool | Part Number | Part Description | Qty |
| A | Test Gauge Hose | ||
| 6V-4143 | Coupler(1) | 1 | |
| 177-7860 | Hose Assembly(1) | 1 | |
| 8T-4188 | Union Adapter(1) | 1 | |
| 6V-3966 | Fitting(1) | 1 | |
| B | Test Gauge | ||
| 8T-0859 | Pressure Gauge(1) | 1 | |
| 6V-4144 | Coupler(1) | 1 | |
| (1) | Part of 4C-4892 ORFS Fittings Group |
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Personal injury or death can result if two persons are not used in the following procedure. |
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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. |
| 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 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. |
- Move the machine to a hard, level surface. The surface must also be dry and free of debris. Engage the parking brake.
- Stop the engine. Place the transmission direction selector in the NEUTRAL position.
- Depress the brake pedal repeatedly in order to release all oil pressure from the brake circuit.
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Illustration 1 g00694410 Location of the Service Brake Control Valve
(1) Test port for the rear service brakes. (2) Test port for the front service brakes.Note: The service brake control valve is located under the operator's cab just behind the steering shaft.
Note: The 836G Landfill Compactor is not equipped with rear service brakes. The 836G Landfill Compactor is equipped with a test port for the front service brakes only.
- Remove the protective cap from pressure port (2) for the front service brakes. Install a 8T-0859 Pressure Gauge pressure gauge.
Reference: For more information on preparing the machine for testing, refer to the Service Manual module Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.
Testing and Adjusting Procedure
- Look at the pressure gauge. Before the engine is started, 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 pressure and normal operating temperature.
- Depress either brake pedal and look at the pressure gauge. Refer to the table below in order to determine the correct brake pressure for the machine that is being tested.
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Table 2 Brake Control Valve Service Brake Pressure Pressure Difference (Upper Port minus Lower Port) 834G Wheel Tractor and 988G Wheel Loader 172-9974 4310 ± 350 kPa (625 ± 50 psi) 210 kPa (30 psi) 200-0866 4726 ± 172 kPa (685 ± 25 psi) 170 kPa (25 psi) 836G Landfill Compactor 129-2359 4310 ± 350 kPa (625 ± 50 psi) N/A - 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 pressure port (1) for the rear service brakes.