TUBE AS 9W1618 - Caterpillar

Personal injury or death can result from sudden machine movement.Sudden movement of the machine or release of air pressure or oil pressure can cause injury to persons on or near the machine.To help prevent possible injury before testing and adjusting any air system or hydraulic system, perform the procedure in the Testing and Adjusting, "General Information" section.
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
Tools That Are Required    
0 to 20680 kPa (0 to 3000 psi) gauge    
Illustration 1 g02505157
Location of the pressure test port
Illustration 2 g02538216
The test port for the parking brake
Install a 0 to 20680 kPa (0 to 3000 psi) pressure gauge on the pressure test port.
Pull out the parking brake control knob in order to engage the parking brake. Start the engine and allow the pressure in the brake accumulators to increase to approximately 15500 to 16500 kPa (2250 to 2400 psi).
Push in the parking brake control knob in order to release the parking brake.
Read the oil pressure on the gauge. When the parking brake is released the correct hydraulic oil pressure should be, 15500 to 16500 kPa (2250 to 2400 psi). Stop the engine.
Depress the brake pedal rapidly several times until the parking brake control knob automatically moves to the engaged position. The parking brake control knob will move outward all the way.
Read the oil pressure on the gauge. The correct hydraulic oil pressure that automatically engages the parking brake should be below 2400 kPa (350 psi).
If the control knob did not move out fully, the operation of the parking brake control valve is not correct. Perform the next two Steps in order to check control components.
Start the engine and allow the accumulator oil pressure to reach 15500 to 16500 kPa (2250 to 2400 psi). Engage and disengage the parking brake in order to check for proper cable and valve movement. The movement should be smooth and free.
Check the parking brake cable for the proper adjustment. If the cable is properly adjusted, replace the parking brake control valve.
A new valve should be tested for proper operation. Recheck using Steps 2 to 7.
Remove the test equipment.