TRAVEL GEAR 0993665 - Caterpillar

Table 1
REQUIRED TOOLS    
Part Number     Description     Quantity    
175-5507     Nitrogen Charging Group     1    Testing and Charging the Return Accumulator
Stop the engine. Release the pressure from the return hydraulic system. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release".Gas pressure is variable with temperature. Check the temperature of the air around the accumulator. In order to check the amount of charge in an accumulator, the accumulator must be at the same temperature as the surrounding air.Note: The temperature of the accumulator may change as the accumulator is being charged due to the expansion or compression of the nitrogen charge. It may be necessary to charge the accumulator in several steps in order to ensure a correct charge.
Table 2
Charge Pressures and Temperatures    
Temperature     Pressure    
-25°C (-13°F)    
220 kPa (31.9 psi)    
-20°C (-4°F)    
225 kPa (32.6 psi)    
-15°C (5°F)    
229 kPa (33.2 psi)    
-10°C (14°F)    
233 kPa (33.8 psi)    
-5°C (23°F)    
238 kPa (34.5 psi)    
0°C (32°F)    
242 kPa (35.1 psi)    
5°C (41°F)    
247 kPa (35.8 psi)    
10°C (50°F)    
251 kPa (36.4 psi)    
15°C (59°F)    
256 kPa (37.1 psi)    
20°C (68°F)    
260 kPa (37.7 psi)    
25°C (77°F)    
264 kPa (38.3 psi)    
30°C (86°F)    
269 kPa (39.0 psi)    
35°C (95°F)    
273 kPa (39.6 psi)    
40°C (104°F)    
278 kPa (40.3 psi)    
45°C (113°F)    
282 kPa (40.9 psi)    
50°C (122°F)    
287 kPa (41.6 psi)    If an accumulator has less than half of the required amount of precharge pressure, the accumulator should be charged. Oil in the accumulator will give an inaccurate precharge reading.
Illustration 1 g00997057
Accumulator (Typical Example) (1) Cap
Illustration 2 g00457381
175-5507 Nitrogen Charging Group (2) Pressure gauge (3) Connection to the nitrogen cylinder (4) Regulator (5) Valve (6) Pressure gauge (7) Pressure regulating screw (8) Valve handle (9) Chuck
Make sure that valve (5) is closed.
Remove cap (1) from the accumulator.
Rotate valve handle (8) on chuck (9) counterclockwise until the valve handle reaches the full out position. Install chuck (9) on the accumulator.
Turn valve handle (8) clockwise until the valve is completely open.
Check the pressure reading on pressure gauge (6) . Refer to Table 2 for the correct charging pressure and temperature relationship for the accumulator.
If the pressure reading on the gauge is too high, use the following steps in order to purge the nitrogen from the accumulator.
Slowly open valve (5) .
Purge the nitrogen pressure until the pressure reading is within the specification.
Close valve (5) .
Turn valve handle (8) on chuck (9) counterclockwise until the valve is completely closed.
Remove the test equipment. Replace cap (1) .
If the pressure is too low, use the following procedure to charge the accumulator:
Turn valve handle (8) on chuck (9) counterclockwise until the valve is completely closed.
Connect the 175-5507 Nitrogen Charging Group to the nitrogen cylinder with connection (3) .
Connect the other end of the hose