Sam92Teg

I have searched all day reading many many posts, and I haven't come across one defective proportioning valve post or one that was malfunctioning.

My 92 RS has a severe bias to the rear brakes. My calipers are fine, they don't drag at all, and I have lubed all the slider pins with silicone grease as required, and all brakes have the same type pad. The rear brakes dust up the rims in the back within a few days and the front brakes are perfectly clean. I have replaced the rear pads 3 times since I have had the car, and the fronts still look 50%. And you can tell that most of the braking is at the rear, which is pretty dangerous.

I believe the car must of sat up for a long time before I purchased it. I am wondering if maybe while it sat, the proportioning valve got all rusted up inside or corroded enough to cause the pressure to all go to the rear brakes and none to the front.

Once again, the calipers don't drag at all when not in use, but most all brake force is going to the rear. The only other thing that I can image causing this would be very weak front brake hoses that might be bulging instead of pushing the caliper piston. Maybe I will just source another valve and swap it in, but would love to hear some ideas before that.

SGVridgerunner

Sounds like air in the front lines. I didn't read that you bled them, maybe try that.

OR... you could adapt your driving style to it and be the best FF drifter in the world!!

RTI

I have never heard of a proportioning valve going bad, but I suppose nothing is impossible. Are you sure the rears are not dragging? If you had all rear and no front brakes you would lock up the rears at every stop since the front normally does almost all the braking on FF cars.

Sam92Teg

Ya, that's whats got me so confused. I have never heard of one going bad. The brakes are bled, and the rears get hot while the fronts are cool under braking and I have only locked the rears up a couple times, but if it is a dirt road, they lock up quick. But they are not seized, after braking, they free spin as normal.

I guess I have the worlds only defective 4040 proportioning valve and no, I won't be shady and sell it to someone in classifieds.

RX3

The proportioning valve adjust the bias from left front to right rear and right front to left rear. As there are two proportioning valve in the same body like you said the chances are both did not fail at the same time. What I have seen is the rubber break line go bad and not let the cailpers retract. And rears are a long run of rubber lines. Hope this help you.

Sam92Teg

Thanks for your replys, I am wondering if I pull the proportioning valve, it there is any way to test it. I have the Helms, and it doesn't even mention the proportioning valve in the brake section.

RX3

I do not know any way to test them. The number stamped on them is the the raito R front to L rear L front to R rear.