SWITCH AS-PRESSURE 1270925 - Caterpillar

Table 1
Required Tools
Part Number Description Qty
8T-5320 Hydraulic Test Group 1
Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.
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.
Note: Before you perform this procedure, release the pressure from the steering system and from the braking system. Also, make sure that the steering frame lock is installed.Reference: For the correct procedure for machine preparation, refer to Testing and Adjusting, "System Pressure - Release".
Illustration 1 g01440177
Left side view
Illustration 2 g01455177
(1) Remote pressure taps
(2) Pressure port for the front service brakes
(3) Pressure port for the service brakes The remote pressure taps (1) are located behind the cab.
Remove the protective cap from pressure port (2) for the front service brakes. Install a 0 to 13800 kPa (0 to 2000 psi) pressure gauge.
Look at the pressure gauge. Before the engine is started, the oil pressure must be at 0 kPa (0 psi).
Start the engine and allow the hydraulic oil to reach normal operating pressure and temperature.
Depress either brake pedal and look at the pressure gauge. The correct brake pressure is 4310 350 kPa (625 50 psi).
If the brake pressure is not within the specification, but the pressure for the front brake accumulator is within the specification, service the service brake control valve.
Repeat this procedure at pressure port (3) for the rear service brakes. Note: The pressure for the rear service brakes should be approximately 210 kPa (30 psi) higher than the pressure for the front service brakes.
Illustration 3 g01440186
Left side view
Illustration 4 g00110244
(4) Pressure port for the front service brakes
Illustration 5 g00110245
(5) Pressure port for the rear service brakes
Note: Pressure ports for checking the front service brake pressure and the rear service brake pressure are also located inside the frame near the top of each axle housing.