SEAL 1479142 - Caterpillar

Personal injury or death can result if two persons are not used in the following procedure.
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, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Refer to Troubleshooting, "Machine Preparation for Troubleshooting" before you perform this procedure.
Table 1
Required Tools
Part Number Description Required Amount
8T-0851 Pressure Gauge (0 to 16,000 kPa (0 to 2,300 psi))(1) 1
6V-4143 Coupler 1
8T-4188 Union Adapter 1
177-7860 Hose As 1
(1) There is one 8T-0851 Pressure Gauge in the 1U-5481 Pressure Gauge Group.Testing the Cut Out Pressure, Cut-In Pressure and Precharge Pressure
Move the machine to a dry, level surface. Stop the engine.
Engage the parking brake. Completely remove all of the oil pressure in the brake circuit by pushing the brake pedal several times.
Illustration 1 g00570463
(1) Accumulator charging valve
(2) Test port
Remove the dust cap from test port (2) for accumulator charging valve (1). Assemble the following components and connect to the test port: 6V-4143 Coupler, 177-7860 Hose As, 8T-4188 Union Adapter and 8T-0851 Pressure Gauge (0 to 16,000 kPa (0 to 2,300 psi)).
Before the engine is started the oil pressure must be 0 kPa (0 psi).
Start the engine. The pressure reading on the gauge should increase to the cut out pressure. Refer to Specifications, "Accumulator Charging Valve" for the appropriate pressures for your machine.
Apply the service brakes several times while the engine is operating. Make sure that the pressure drops consistently. The pressure reading on the pressure gauge will rapidly increase when the cut-in pressure is reached.
After the brake accumulators have been charged, stop the engine.
Turn the engine start switch to the RUN position. Do not start the engine.
Illustration 2 g00570464
(3) Low brake pressure indicator
Apply the brakes several times. When the pressure on the gauge decreases to the cut-in pressure, low brake pressure indicator (3) on the dash will turn on. This indicates that the low brake pressure switch and the alert indicator work.
There will be a point when the reading on the pressure gauge will drop rapidly. This pressure is the approximate precharge pressure of the accumulator. Refer to Specifications, "Accumulator" for the appropriate accumulator precharge pressure. Note: The number of brake applications before the rapid decline in pressure should be between four and six.
Refer to Testing and Adjusting, "Brake Accumulator - Test and Charge" if the accumulator precharge pressure is not correct. Continue to Step 12 only if the cut out pressure is incorrect. Adjusting the Cut-In Pressure and the Cut Out Pressure
Turn the engine start switch to the OFF position.
Completely remove all oil pressure from the brake circuit by pushing on the brake pedal many times until there is no brake pressure. Make sure that there