Rear Brake Fix - Proportioning Valve Modification 8-24-02

History behind this modification:

Almost all '84-'88 Rear disc brake Camaro and Firebirds have rear brake systems that do not work correctly. The problem was originally thought to be the calipers and GM issued a recall for these cars but only if they where 5-speeds since the problem was affecting the e-brake. If you had an automatic, well lets just say you did not have to worry about replacing your rear brake pads. When I I was looking at mine when I bought the car the rotors looked like they had been freshly turned. They stayed that way for almost a year! Early in 2001 GM re-introduced the rear caliper recall kit which could be purchased at any GM dealership for around $140. It included a new piston, seals, and other misc. parts to do the job. I thought about doing the same for mine but then I heard about people who had bought the kit, installed, and their brakes still did not work so I held off on it.
Then about 2 months ago I found a link off of a thirdgen.org message board thread that went to a message on gmforums.com. A GM service guy had been trying to figure this out and found the answer. It is not that the calipers do not work, its the fact that no fluid is getting to them. The source of this is the proportioning valve. This is the valve that determines how much fluid travels to the front and rear brakes. The information below is what is needed to fix it.

* NOTE: if you '89 - '92 PBR Rear calipers, DO NOT DO THIS MODIFICATION.
If you are not sure if you have PBR calipers, look at the picture below. Notice the "ribs" on the sides of the calipers.

First, examine your entire brake system including rotors, pads, fluid level, master cyliner, lines, and any traces of brake fluid that might be leaking. If you see something that is not right, you need to fix it! Brakes are the most important part on your car, do not neglect them.

Tools needed for this modification:

* 13/16" socket and socket wrench
* Needle nose pliers
* 1 quart of brake fluid
* 5/8" - 18 3/4" intake plug
* 5/16" Hex (Alan) wrench
* Teflon tape
* Old rags or paper towels

1. You will want to remove the rubber boot convering up the proportioning valve (PV) bleeder point.

2. Lay down your old rags or paper towels under the PV to catch any fluid that might come out.

3. Take your 13/16" socket wrench and remove the the plug. There is a spring behind it so you will want to keep some pressure on it as you unscrew it. Once it is off you will see the spring and piston inside. Also notice that hardly any fluid came out. *That is the problem, it should be full of fluid.

4. Take some needle nose pliers and pull out the spring and the piston inside the PV. It should not take too much strength to pull it out. Also take your paper towl and clean threads off since you have the plug off.

5. Take the intake plug and wrap about two layers of teflon tape around it.

Here are some pics of the old and new plug side by side.

6. Take your alan wrench and screw the plug back in.

You will now need to bleed your rear brakes really good. Do not try to bleed the PV or master cylinder to get the air out. By bleeding the rear brakes you will fill the PV up and work the air out. It will take a while but be patient. If you do not know how to bleed your rear brakes consult a mechanic or maintance book for your car.

So far I am very happy with the results of from doing this modification. I have alot more pedal pressure and the car does stop quicker. It still does not stop as well as I would like it to but taking into consideration the brakes on most 3rd Gen F-body cars are too small anyway, I think they will work for now.

Maybe Santa Clause can bring me a Baer brake system for Christimas!!!