OPERATIONAL PERFORMANCE TEST / Component Test PRIMARY PILOT PRESSURE (Including Brake Circuit) CAUTION: If air is mixed in the brake system, the brake function is reduced, and serious hazard may occur. Bleed air from the brake system after removing and installing the pipe lines and replacing hydraulic oil. Refer to Troubleshooting B in Group T5-6. IMPORTANT: Primary pilot pressure circuit shuts off a circuit connecting to pilot relief valve if pressure in the accumulator is insufficient, and delivers primary pilot pressure to accumulator circuit.
At this time, primary pilot pressure reaches 15 MPa (153 kgf/cm 2 , 2180 psi) or high, so use a pressure gauge capable of measuring 15 MPa (153 kgf/cm 2 , 2180 psi) or higher. Preparation: 1. Stop the engine. 2. Push the air bleed valve on top of the hydraulic oil tank and release any remaining pressure. 3. Remove the hose end from the pilot filter inlet or outlet port. Install adapter (13/16-16UNF), nipple, pressure gauge and coupling. Hose (3/4-16UNF) Pilot Filter T4GB-04-05-001 4. Start the engine. Check for any oil leaks at the pressure gauge connection. 5. Maintain the hydraulic oil temperature at 50 ± 5 ° C (122 ± 41 ° F). : 22 mm, 24 mm, 27 mm Measurement: 1.
Set engine speed at fast idle. Depress the accel- erator pedal fully. 2. Measure pilot pressure without load by using a pressure gauge. 3. Repeat the measurement three times and calcu- late the average values. T1F3-04-05-001 Evaluation: Refer to the Performance Standard Table in Group T4-2. NOTE: When pressure in the service brake ac- cumulator is reduced during measurement of primary pilot pressure, the measured valve is increased to 15 MPa (153 kgf/cm 2 , 2180 psi) for several seconds. T4-5-1