KIT-BEARING 3054142 - Caterpillar

Top View
Location Of Brake Component Access Panel (Arrow)The parking brake control valve is located in the engine end frame of the machine under the access panel to the rear of the operator's platform. It is to the right of the two accumulators. The valve controls the flow of pressure oil to and from the parking brake actuator.
Top View Parking Brake Control Valve Location
(1) Parking brake control valve.
Parking Brake Control Valve (Parking Brake Shown In The Engaged Position)
(2) Pressure port from brake accumulators. (3) Parking brake control knob stem. (4) Spring. (5) Spool. (6) Return to tank port. (7) Spool. (8) Parking brake actuator port. (9) Retainer. (10) Spring. Hydraulic tank pressure above 210 kPa (30 psi) may result in parking brake control knob stem (3) being extended to the position shown (parking brake engaged).
Parking Brake Control Knob Pushed In (Parking Brake Disengaged)
(11) Parking brake control knob.When parking brake control knob (11) in the operator's compartment is pushed in (parking brake disengaged), spool (7) and retainer (9) move to the right to compress spring (10). This allows pressure oil to flow into the pressure port from accumulators (2), and out parking brake actuator port (8). From parking brake actuator port (8), the pressure oil flows to a cavity in the parking brake actuator assembly.When the pressure of the oil in the brake actuator cavity is high enough to compress the spring in the actuator, the brake will disengage. This oil pressure keeps the parking brake disengaged.
Parking Brake Knob Pulled Out (Parking Brake Engaged)
(11) Parking brake control knob.If parking brake control knob (11) in the operator's compartment is pulled all of the way out (parking brake engaged), parking brake control knob stem (3) stops the flow of oil from the accumulator to the parking brake. Moving parking brake control knob (11) causes spool (7) to move left. This stops the supply of oil from the accumulators and dumps the actuator oil back to the tank.With the drop in brake system oil pressure, the force of the spring in the brake actuator assembly is greater than the pressure of the oil in the cavity of the actuator assembly. This allows the spring in the actuator to engage the parking brake.If there is an oil pressure drop in the brake system during machine operation, the parking brake control valve will automatically engage the parking brake.With a loss of hydraulic oil pressure, the force of spring (4) will move spool (5) to the right. This blocks any flow of oil that would normally help keep spring (10) compressed. With no oil pressure compressing spring (10), the force of spring (10) moves spring retainer (9), spool (7), and parking brake control knob stem (3) out.
Alert Indicator And Master Action Light Locations
(12) Parking brake alert indicator. (13) Low oil pressure alert indicator. (14) Master action light.When the hydraulic oil pressure to the parking brake actuator drops below 6890 345 kPa (1000 50 psi), the Caterpillar Monitoring System will indicate a Category 3 warning.