TANK AS-EXPANSION 1743235 - Caterpillar

Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.Always use a board or cardboard when checking for a leak.
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.
Specifications
Table 1
Specifications
Pump Cut-out Pressure 21000 350 kPa (3046 51 psi)
Cut-in/Cut-out Valve Cut-in pressure 12066 345 kPa (1750 50 psi)
Cut-out pressure 15513 345 kPa (2250 50 psi)
Hydraulic System Pressure Anticipated Action Actual Result
Less than 700 kPa (100 psi) The parking brake control knob will move outward full stroke Introduction
This procedure will test the parking brake control valve for the pressure at which the parking brake will automatically engage.Required Tools
Illustration 1 g02726620
Table 2
Required Tools
Tool Item Qty Part Number Description
B B1 1 8T-0852 Pressure Gauge
B2 2 6V-4143 Quick Connect Coupler
B3 1 6V-3079 Hose As
B4 1 6V-3966 Fitting Test Preparation
Prepare the machine for testing by completing the procedure that is specified in the Service Manual module Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.Test Procedure
Illustration 2 g06275926
(3) Parking brake control valve
Illustration 3 g06275927
Pressure Ports for Checking the Brake Pump Discharge
(1) Pressure test port for rear brake accumulator
(2) Pressure test port for front brake accumulator
(41) Brake accumulatorsThe operator cab and the platform have been removed for clarity in this view.
Attach the correct hose to pressure tap (1). Use the correct pressure gauge.
Start the engine and allow the accumulator oil pressure to increase to the cut-in pressure.Note: Keep the engine running. Allow the accumulator oil pressure to reach cut-out valve pressure of 15513 345 kPa (2250 50 psi).
Place the parking brake control knob in the disengaged position. Verify that the parking brake is disengaged. Stop the engine.
Push 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.
If the hydraulic pressure decreases to less than 700 kPa (100 psi), the parking brake control knob should move outward full stroke. 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.Note: The parking brake control valve is designed as a manually released valve.
Start the engine and allow the accumulator oil pressure to reach cut-out pressure. Engage and disengage the parking brake in order to check for proper cable and valve movement.