FITTING SCREW 1481160 - Caterpillar

A change in the braking characteristics or a low pressure warning may be an indication of a failure in one of the brake circuits. Personal injury or death may occur if the machine is operated before repairs have been made or before all circuits have been checked. Always check the brakes after brake repairs have been made and before the machine is put back into use.
Use two 8T-0849 Pressure Gauge Group in order to check the delivery pressure for the service brakes on both sides of the machine. Connect the gauges to delivery ports (4) and (6).
Illustration 1 g00627729
Service Brake Control Valve (1) Plunger boot (2) Plunger (3) Rubber spring (4) Delivery port (5) Inlet and exhaust valve (6) Delivery port (7) Inlet and exhaust valve (8) Exhaust portApply the service brake control and release the service brake control multiple times. Check the delivery pressure on the test pressure gauges in order to verify that the air pressure changes. The air pressure should be the same amount for both the left service brakes and the right service brakes when the pedal is moved.Apply the service brakes fully. Release the service brakes. Immediately after releasing the service brakes, the reading on the test pressure gauges should read 0 kPa (0 psi).When the air pressure in each section of the air tank is identical, the delivery air pressure should be within 35 kPa (5 psi) of each test pressure gauge. This is normal for this service brake control valve.Remove the pressure gauge groups and install hoses to ports (4) and (6) .Check the Service Brake Control Valve for Leakage
Keep the air pressure at 795 to 965 kPa (115 to 140 psi) while you apply the service brakes and hold. Apply a mixture of soap and water on exhaust port (8). Permissible leakage is a 25.0 mm (1.00 inch) bubble in three seconds. If the leakage is more than a 25.0 mm (1.00 inch) bubble in three seconds, repair the service brake control valve. After the repair has been made retest the service brake control valve.