TUBE A. 2D0167 - Caterpillar

Stop the engine.Nitrogen gas pressure varies with the temperature. To obtain the most accurate nitrogen charge, the temperature of the accumulator must be identical to the air temperature around the accumulator.If the accumulator has less than half of the required amount of precharge pressure, the accumulator should be charged. Then charge the accumulator again after you shift speeds repeatedly in order to prevent trapping oil in the accumulator. Oil in the accumulator will give an inaccurate precharge reading.However, the temperature of the accumulators could be higher than the air temperature around the accumulators. In this case, the temperature of the accumulator should be used instead of the surrounding air temperature.Note: The pressures in the following two tables are for an ambient air temperature of 20°C (68°F). Adjust the pressure for other ambient conditions, as required.
Table 1
Accumulator Precharge Pressure/Temperature Relationship for a Typical
1300 kPa (190 psi) Accumulator (Transmission Gearbox)
554 Forwarder    
Temperature     Pressure    
-10°C (14°F)    
1167 kPa (169 psi)    
-5°C (23°F)    
1189 kPa (172 psi)    
0°C (32°F)    
1211 kPa (176 psi)    
5°C (41°F)    
1233 kPa (179 psi)    
10°C (50°F)    
1256 kPa (182 psi)    
15°C (59°F)    
1278 kPa (185 psi)    
20°C (68°F)    
1300 kPa (189 psi)    
25°C (77°F)    
1322 kPa (192 psi)    
30°C (86°F)    
1344 kPa (195 psi)    
35°C (95°F)    
1366 kPa (198 psi)    
40°C (104°F)    
1388 kPa (201 psi)    
45°C (113°F)    
1410 kPa (204 psi)    
Table 2
Accumulator Precharge Pressure/Temperature Relationship for a Typical
1600 kPa (230 psi) Brake Accumulator
574 Forwarder    
Temperature     Pressure    
-10°C (14°F)    
1437 kPa (208 psi)    
-5°C (23°F)    
1462 kPa (212 psi)    
0°C (32°F)    
1491 kPa (216 psi)    
5°C (41°F)    
1518 kPa (220 psi)    
10°C (50°F)    
1546 kPa (224 psi)    
15°C (59°F)    
1573 kPa (228 psi)    
20°C (68°F)    
1600 kPa (232 psi)    
25°C (77°F)    
1627 kPa (236 psi)    
30°C (86°F)    
1654 kPa (240 psi)    
35°C (95°F)    
1682 kPa (244 psi)    
40°C (104°F)    
1709 kPa (248 psi)    
45°C (113°F)    
1736 kPa (252 psi)    
Illustration 1 g00558069
Location of accumulator (underneath fuel tank)
Illustration 2 g00535595
Accumulator (1) Cap. (2) O-ring seal. (3) Screw. (4) Accumulator valve.
Illustration 3 g00535589
Nitrogen Charging Group (5) Charging hose fitting. (6) Pressure gauge. (7) Valve body. (8) Knob. (9) Accumulator purge valve. (10) Charging hose. (11) Adapter.Note: The accumulator is located underneath the fuel tank on the left side of the front frame.
Remove cap (1) and O-ring seal (2) from the accumulator.
Loosen screw (3) half of a turn with an allen wrench.
Screw adapter (11) onto accumulator valve (4) .
Open accumulator valve (4) with knob (8). When the needle of the pressure gauge begins to move, turn knob (8) with one complete turn. Check the temperature of the air around the accumulator. The reading on the pressure gauge must be within the tolerances. For the correct charging