MODULE AR-EXH 4940358 - Caterpillar

Table 31
Accumulator Precharge Pressure/Temperature Relationship for a Typical Accumulator with a Precharge of
4500 kPa (650 psi)    
Temperature     Pressure    
-18 °C (0 °F)    
3905 kPa (566 psi)    
-12 °C (10 °F)    
3990 kPa (579 psi)    
-7 °C (20 °F)    
4075 kPa (591 psi)    
-1 °C (30 °F)    
4160 kPa (603 psi)    
4 °C (40 °F)    
4245 kPa (616 psi)    
10 °C (50 °F)    
4330 kPa (628 psi)    
16 °C (60 °F)    
4415 kPa (640 psi)    
21 °C (70 °F)    
4500 kPa (653 psi)    
27 °C (80 °F)    
4585 kPa (665 psi)    
32 °C (90 °F)    
4670 kPa (677 psi)    
38 °C (100 °F)    
4755 kPa (689 psi)    
43 °C (110 °F)    
4840 kPa (702 psi)    
49 °C (120 °F)    
4925 kPa (714 psi)    
54 °C (130 °F)    
5010 kPa (726 psi)    
60 °C (140 °F)    
5095 kPa (739 psi)    
66 °C (150 °F)    
5180 kPa (751 psi)    
71 °C (160 °F)    
5265 kPa (763 psi)    
77 °C (170 °F)    
5350 kPa (776 psi)    
82 °C (180 °F)    
5435 kPa (788 psi)    Refer to Service Manual module, RENR2171-02, "Testing and Adjusting, 988G Wheel Loader Hydraulic System", "Ride Control Accumulator - Charge Procedure". The precharge pressure in Step 13 is incorrect. The corrected step is given below.
Adjust pressure regulating screw (12) in order to obtain a pressure reading of 4500 kPa (650 psi) on gauge (5) .Note: 4500 kPa (650 psi) is the appropriate pressure for the accumulator when the ambient temperature is 21 °C (70 °F). If the machine has been running for some time the temperature of the accumulator may be different from the ambient temperature of the outside air. Refer to Table 31 for the proper pressure.