EDGE-CUTTING 4T6372 - Caterpillar

Illustration 1 g00804260
(1) Solenoid valve (2) Port (pressure switch) (3) Port (accumulator) (4) Check valve (5) Test port (6) Pump port (7) Tank port (8) Port (parking brake)
Illustration 2 g02463423
(1) Solenoid Valve (4) Check Valve (5) Test Port (9) Accumulator (10) Pressure SwitchThe brake control valve (parking) serves two purposes. The first purpose is the operation of the parking brake. The second is the engagement of the parking brake when there is no power in the electrical system.The brake control valve (parking) is located inside the right side of the rear frame and in front of the center axle.Pump port (6) is connected to the piston pump for the braking system. Port (3) is connected to accumulator (9) for the parking brake. The brake control valve (parking) is connected to the ECM by the connection to solenoid valve (1) .When the parking brake control in the cab is moved to the DISENGAGED position, the solenoid valve is energized. The spool of the solenoid valve is moved against a spring. Oil flows from pump port (6) and port (3) to port (8) which is connected to the parking brake. The parking brake is disengaged.When the parking brake control in the cab is moved to the ENGAGED position, the solenoid valve is de-energized. The spool of the solenoid valve is moved by a spring. Oil from pump port (6) and port (3) is blocked by the spool. The spool directs oil from the parking brake to tank port (7). The parking brake is engaged by spring force.Check valve (4) maintains pressure in the accumulator if pressure in the line from the piston pump falls below the oil pressure inside the accumulator.Pressure switch (10) sends a signal to the ECM. When there is no pressure in the line to the parking brake, an indicator light in the cab is activated. This indicator is activated in order to show the engagement of the parking brake.