Brakes in all 4 corners locking up at startup.

[terrence]

Yea, I have a 95 s14 that I have been having problems with my brakes for a while now. At first I thought it was the front calipers because only they were locking up after the car had been sitting for awhile. Bleed the system and it rolled just fine. Took it around the block and locked up again after about 2 miles. Replaced the BMC and took the car out again, no problems (only went about 5miles away and back).

Go to move the car about 1 week later and locked on all four corners. Come back a week later and jack the car up, all 4 wheels spin freely. Start the car and all 4 corners lock up instantly.

I have no idea where to go from here and it is pretty much a roadblock for any future projects.

[ta2maki]

Come back a week later and jack the car up, all 4 wheels spin freely. Start the car and all 4 corners lock up instantly.

That sounds like the brake booster is bad. Disconnect vacuum to the booster and test.

[shinobis13hb]

how does the pedal feel?

[racepar1]

I've seen that before on a toyota truck, the brake booster was bad. Start there...

[Rockda240]

I had the same problem before when I replaced the brakes, you should rebleed them!

[terrence]

That sounds like the brake booster is bad. Disconnect vacuum to the booster and test.

Disconnected the vacuum and nothing changed. Whenever I released the bleed screw all 4 wheels rolled again so I guess that has something to do with it. This is what I have done before to get the car rolling, but it is only a temporary fix. They always lock up again whether it is sitting or going for a short drive they do lock up again.

how does the pedal feel?

Very stiff at first, then I release pressure from bleed screw they went back to normal.

I've seen that before on a toyota truck, the brake booster was bad. Start there...

How do I know for sure that it is the booster?

I had the same problem before when I replaced the brakes, you should rebleed them!

Bleed them many times since the problem has risen, only temporarily fixes it.

[Sam_Well.13]

Brake booster is your only way out of this problem, if you done what you said you did. Then the only problem could just be the brake booster. Not alot of parts for brake system, just the matter of breaking it down. Unless you have ABS, but im not sure if that affects locking. It could but dont hold me up to it. I never owned any ABS S-chassis.

Goodluck though and post your verdict to w/e it maybe that fixes it.

[terrence]

So yea, bleed the breaks Sunday so that it could roll, left brake booster disconnected and let the car sit. Went out today to roll it again to see if it was locked and yea, all 4 wheels are solid locked. How would the booster lock them if it wasn't connected and the car was not running in between the time they were locked up and now locked up. So something has to be putting pressure on the fluid/calipers/something somewhere.

I'll try pulling the caliper tonight when I get off work, fuck working on the car in the open when it's 92 degrees outside.

Trouble shooting sucks..

[shinobis13hb]

go to the wrecking yard and pull off a booster and try it out.

[Jbma327]

Try getting a different brake booster. And you can also asjust the push rod(rod that pushs the brake master) on the brake booster. Try shortening the rod.