What are the signs of a bad proportioning valve? I tried the search, but that was worthless. Also, where can I find a new one? Thanks.

 

Signs? Well, what's happening with your brakes to make you think you need a new prop valve?

Ah ha, I'm a senior member once again. Hello 500th post. Where's my social security check?

Edit: Did you see this thread and this one?

 

Jack up the rear end of your car.
Place jack stands under the rear axles.
Put car in drive and hit the brakes.

Wheels stop - valve probably OK
Wheels don't stop - valve maybe not OK.

I just removed the prop valve from my car before. It gave the back brakes a little too much grab, but at least they worked again.

The prop system in the GTA's sucks. Most people recommend getting a Willwood system.

 

first make sure that therear brakes dont need replaced or adjusted out it is comon for the adjusters in the rear to sieze up over the years due to rust and not adjust out in which will keep the pedal low all the time when you stop, will need excessive pedal travel to stop and wont go away until you get new adjusters and put the shoes all the way out to the drums

check that first

its VERy rare for a combo prop valve to go bad

extremely

i would suspect this last

after eveything else

good luck

 

Good points. I think in my case, there may have been some stiction in the rear calipers and removing the prop valve gave them enough pressure to start working again.

 

Well then this is most likely not a bad proportioning valve thats wrong then. The problem is the car pulls to the right(most of the time) and always squeals on the right front. Everything possible is new except the master cylinder and proportioning valve of course. I have replaced the calipers twice and pads twice. One thing that got me this time was that the pads had cracks in them. They were the cheapest ceramic pads you could by but a lot more expensive then the cheapest pads. But the right side had more cracks then the left...tells me more stress was going on the right side then the left. This whole time we were not sure if it was a sticking caliper, or a misadjusted caliper. Well i replaced both side calipers again and they were put on at the same time so i know they are the same...i cleaned up the rotors and pads and the squealing and most the pulling went away for about a week. Its back and its intermidiate...like some days it squeals a lot others it doesnt. Temperature im sure.

Sorry i write a lot. I think I/We are going to return the pads and get a more expensive brand...who knows...

Thanks for the help.

 

My 91 RS has this same problem only on the driver side and I tryed the cheap $36 ceramic pads at advance auto and I had the same cracking on the pads. They were also rainbow colored as if they got too hot. Yesterday I got the cheapest set of semi mettalic pads and changed my driver side rotor (the ceramic pads tore it up bad!) and I will tell you guys what happens. I did not do much but skim this thread but did you try changeing the flex lines to the calipers? That will be the next thing I try.

 

Yes we did. I think that was the original problem. The passenger side was leaking so we changed that one first and left the driver side alone. We were told that this would cause uneven diameters in the hoses since one was new and the other old causing fluid to get to the passenger side first and thus make the car pull this way. However, having the driver's side hose changed only helped a little and the caliper that we pulled off the passenger side had the piston stuck partially out. So it still pulls to the right needless to say and it's getting quite frustrating.

 

Wow thats not good I will be working on mine some today and I will keep you guys posted if I get any other ideas.

 

If you got a situation where partial pedal braking (normal braking) and it doesn't pull, and pulls hard to one side when brakes are applied forcefully (such as an emergency stop) then I would bet you have some bad rubber brake lines. That's if the car is driving straight down the road and doesn't pull to one side. This was the situation I had-replaced both lines at the same time, front and rear, problem solved. You have already checked the caliper pistons, and as long as they are working properly, I would suspect those hoses.

They're not that expensive and should be replaced anyhow if you went through the rest of the brakes already, completes the job and one less thing to worry about in the future. First time the some 'old lady' pulls out in front of you, you'll be glad you did!

 

The rubber lines have all been changed. The only things that haven't are the proportioning valve, master cylinder, brake booster, and some of the actual brake line. I know it's not my alignment as that pulls to the left. What's funny is the brakes don't pull ALL the time. Even on the same stretch of road, sometimes they will pull sometimes they won't, but that right side almost always squeaks. I think I'm going to return the crappy pads and try another new set.

 

I love brake problems