SPACER 1281842 - Caterpillar

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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products.Dispose of all fluids according to local regulations and mandates.
Table 1
Required Tools
Part Number Description
7S-5437 Nitrogen Charging Equipment
Illustration 2 g01211875
Location of the Brake Accumulators
(3) Accumulators
(4) Cap
(21) Hydraulic Oil Tank for the Brake and Implement Systems Hydraulic brake accumulators (3) are located in front of the hydraulic oil tank. This tank is located on the right side of the machine.Stop the engine. Depress the brake pedal repeatedly until there is no brake pressure.To ensure that the nitrogen charge is correct, each brake accumulator piston must be at the bottom of the accumulator cylinder. Nitrogen gas pressure varies with the temperature. To obtain the most accurate nitrogen charge, the temperature of each accumulator must be identical to the air temperature around the accumulators.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 table are for an ambient air temperature of 21°C (70°F). Adjust the pressure for other ambient conditions, as required.
Table 2
Accumulator Precharge Pressure/Temperature Relationship for the 5520 kPa (800 psi) Service Brake Accumulator
Temperature Pressure
−7°C (20°F) 5000 kPa (726 psi)
−1°C (30°F) 5105 kPa (741 psi)
4°C (40°F) 5235 kPa (760 psi)
10°C (50°F) 5340 kPa (775 psi)
16°C (60°F) 5420 kPa (787 psi)
21°C (70°F) 5500 kPa (798 psi)
27°C (80°F) 5605 kPa (813 psi)
32°C (90°F) 5735 kPa (832 psi)
38°C (100°F) 5840 kPa (848 psi)
43°C (110°F) 5920 kPa (859 psi)
49°C (120°F) 6000 kPa (871 psi)
Illustration 3 g00855511
Nitrogen Charging Equipment
(5) Nipple. (6) Coupling assembly. (7) Pressure gauge. (8) Hose assembly. (9) Coupling assembly. (10) Nipple. (11) Valve. (12) Pressure gauge. (13) Regulator assembly. (14) Pressure regulating screw. (15) Chuck for the nitrogen cylinder valve. (16) Valve handle. (17) Chuck. (18) Hose assembly.
Illustration 4 g00855446
(19) Cover
(4) Cap
(20) Nitrogen charging valve
In order to release any oil pressure that is in the accumulators, apply the service brakes repeatedly. This may require more than ten applications of the brakes.
Remove cover (19) from the brake accumulator. Remove cap (4) from the valve assembly on the brake accumulator.
Use a 20700 kPa (3000 psi) pressure gauge (12) to check the nitrogen charge in the brake accumulator.
Turn valve (11) and valve (16) clockwise in order to close the valves. Install chuck (17) onto nitrogen charging valve (20) for the brake accumulator.
OPEN valve (16) by turning counterclockwise slowly in order to check the nitrogen pressure that is in the accumulator. Refer to Table 2.
Check the temperature of the air around the brake accumulator. The