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View Full Version : Recentering Brake Proportioning Valve



Mtn WJ
07-22-2004, 04:19 PM
I seem to be having some inconsistant braking issues. At times I seem to have much less braking power and the pedal goes to the floor more than it should. My pads and rotors are in good shape and I bled the brakes. I have had bad master cylinders in other vehicles and I do not think it is the MC. Once the pedal is pushed it does not creep down any farther like a bad MC would do. I have heard of similar issues with a bad proportioning valve. One guy said I may need to recenter it. Has anyone had this issue and or has anyone recentered a proportioning valve on their WJ/ZJ. I replaced my brake lines in January and this may have been when my proportioning valve issue started. Any suggestions would be appreciated.

Keith S

anthonyh75
01-18-2005, 05:24 PM
i am having the same problem with my brakes. I replaced the proportionng valve and that didnt solve the problem. My problem started when I replaced my MC.

OverkillZJ
01-18-2005, 05:59 PM
Intereesting... I thought Ive had air leaking somwhere into the system, but maybe I'm having similar problems as well.

JpRngr
01-18-2005, 09:42 PM
Keith,
Usually an uncentered valve will turn on a brake light. It was a front hose that blew, correct? Try having someone mash down the pedal(engine off), while opening the opposite rear bleeder screw. Doing this is usually how we recenter the valve when the light is triggered.

Also, is it possible that you sucked some air into the ABS when it blew? Did the MC go dry?


Corey

anthonyh75
01-19-2005, 10:13 AM
Yeah usually the light will come on. This is what I have found on checking it.

METERING VALVE
Metering valve operation can be checked visually with the aid of a helper. Observe the metering valve stem while a helper applies and releases the brakes. If the valve is operating correctly, the stem will extend slightly when the brakes are applied and retract when the brakes are released. If the valve is faulty, replace the entire combination valve as an assembly.

PRESSURE DIFFERENTIAL SWITCH


Have helper sit in drivers seat to apply brake pedal and observe red brake warning light.
Raise vehicle on hoist.
Connect bleed hose to a rear wheel cylinder and immerse hose end in container partially filled with brake fluid.
Have helper press and hold brake pedal to floor and observe warning light.
If warning light illuminates, switch is operating correctly.
If light fails to illuminate, check circuit fuse, bulb, and wiring. The parking brake switch can be used to aid in identifying whether or not the brake light bulb and fuse is functional. Repair or replace parts as necessary and test differential pressure switch operation again.
If warning light still does not illuminate, switch is faulty. Replace combination valve assembly, bleed brake system and verify proper switch and valve operation.