Bad brake problem, please help!

[broke30]

Well hey all,
I have been looking on these forums for quite some time after wandering over here from bf.c. Anyways, I am having a brake problem. First of all, my abs light is always on even after replacing the computer and relay (with a used one). The main problem is with the brakes locking up. When you first begin to drive the car the pedal will move about 2-3 inches then brake, however after driving for a short distance the rear brakes seem to seize up and it brakes on its own and the pedal is completely stiff. I just put new calipers, rotors and pads. Any other suggestions? Thanks in advance
Max

[Mike325]

Hey, welcome to the forum. Sounds like the poportioning valve may be no good. This will limit the pressure to the rear brakes so they won't lock up. Could also be a bad master.

[broke30]

I may not have typed my description very clear but that is whats happening. The rear brakes will lock up and start smoking... The pedal will have almost no movement and the rear brakes will just stop the car without me pushing on the pedal...
Max

BTW Thanks for the welcome!

[Mike325]

Oh, so the rear brakes will lock up without any pedal imput from your foot? Seems like you could have a bad master. Like maybe it is only putting pressure to the rear brakes. Could be a clogged port in it.

[broke30]

I thought about that, but the brakes bled just fine, and its only when the car kind of "heats up" I guess. After a little travel time... I almost thought it was an abs problem but I'm really not sure...

[Mike325]

So just to clarify, the rear brakes lock up totally by themselves?

[broke30]

Yes, exactly...
Max

[broke30]

Well now all four calipers as of today are starting to seize up after driving a short distance... Any more suggestions anyone?
Max

[Mike B.]

Check your brake booster / non-return valve.

[broke30]

What is a non-return valve?
Max

[Mike B.]

It's the valve that helps maintain proper vacuum in the booster. Follow the line from the intake to the booster and you will see it inline.

You may also want to see if your ABS pump is functioning properly.

[broke30]

Thats what I was originally told is that it was the abs pump. I bought another one and I will check it tonight. Is there any way to check it? Like if I pulled the abs fuse that would disconnect it but would the valves inside still cause problems?
Max

[Mike325]

I would pull the fues yes. Have you tried bleeding the brakes ever? There was a member a little while ago that had an abs pump not work on him. His brakes would not bleed, but there was pressure into the abs pump, but not out of it.

[broke30]

Yes I have bled the brakes numberous times as stated in my first post. I am still suspecting the abs pump I guess, I pulled the fuse and haven't really had the problem however I haven't driven too far yet...
Max

[netcsk]

Still sounds like the proportioning valve to me. Sounds like the valve is not working correctly by not letting the fluid return back completely once the pedal is pressed in.