Dodge Durango

 Service Manual

Brakes » Base brake system » Description and operation
Combination valve

The combination valve contains a pressure differential valve and switch and a proportioning valve.

The combination valve/proportioning valve are not repairable and must be replaced as an assembly.

PRESSURE DIFFERENTIAL SWITCH

The pressure differential switch is connected to the brake warning lamp. The switch is triggered by movement of the switch valve. The purpose of the switch is to monitor fluid pressure in the separate front/rear brake hydraulic circuits.

A decrease or loss of fluid pressure in either hydraulic circuit will cause the switch valve to shuttle forward or rearward in response to the pressure differential. Movement of the switch valve will push the switch plunger upward. This closes the switch internal contacts completing the electrical circuit to the warning lamp. The switch valve may remain in an actuated position until repair restores system pressures to normal levels.

PROPORTIONING VALVE

The proportioning valve is used to balance frontrear brake action at high decelerations. The valve allows normal fluid pressure during moderate braking.

The valve only controls fluid pressure during high decelerations brake stops, when a percentage of rear weight is transferred to the front wheels.

Brake system

Service warnings & cautions

Brake pedal

Stop lamp switch

Red brake warning lamp

Power brake booster

Master cylinder

Combination valve

Front disc brakes

Drum brakes

Parking brakes

Brake hoses and lines