Dakota 4WD V8-5.2L VIN Y (1998)
Brake Proportioning/Combination Valve: Description and Operation
GENERAL INFORMATION
The combination valve contains a pressure differential valve and switch and a rear brake proportioning valve. The valve is not repairable and must
be replaced as an assembly if diagnosis indicates this is necessary.
Pressure Differential Valve
The pressure differential switch is connected to the brake warning light. The switch is actuated by movement of the switch valve. The switch
monitors 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 to the low pressure side. Movement of the valve
pushes the switch plunger upward. This action closes the switch internal contacts completing the electrical circuit to the red warning light. The
switch valve will remain in an actuated position until repairs to the brake system are made.
Proportioning Valve
The proportioning valve is used to balance front-rear brake action at high decelerations. The valve allows normal fluid flow during moderate
braking. The valve only controls fluid flow during high decelerations brake stops.