front brakes not releasing

[REDse86]

Alright here it goes.

A couple of weeks ago I purchased my first Fiero, a 86' SE. It has sat for 3 years so the brakes were in pretty poor shape. So far I have replaced everything brake related in the rear end, excluding the left rear flex line. (I plan on doing that soon) In the front I replaced the rotors and the pads.

When I bleed my brakes, the rear works perfect, no binding or anything. The fronts however are giving me problems. The first time I apply the pedal the fronts grab the rotor and don't let go. I have come to believe that something is not letting the fluid back into the reservoir.

I understand that the combination / proportioning valve blocks off the front or rear if there is a big leak. I have also thought that maybe the flex lines have collapsed in such a way that it will let fluid through but it wont let it return.

Any suggestions on what to do? Should I replace the proportioning valve? Does anyone have a exploded view of it? :scratch:

Thanks for the help!

[The Dark Side of Will]

I'd replace the front flex lines first.

[REDse86]

I just removed the LF caliper. When I removed the flex line from the caliper the piston did not retract into its bore. Shouldn't it release the rotor?

I used a C clamp to press the piston into the caliper. It was quite tough going back in. I removed the caliper and pushed the piston out and found no rust or corrosion anywhere. I believe the calipers need to be replaced.

[Dirty Sanchez]

Since your car has been sitting so long it probably needs the calipers rebuild, you also should replace the rubber brake lines with new ones. The old ones tend to swell on the inside and can act as one way valves preventing the brakes from releasing.

[The Dark Side of Will]

If the piston is stiff but not corroded, you can usually free it up by cycling it in and out several times.

[REDse86]

thanks for the replies guys! Ill work on getting parts Tuesday.

[Mlevair]

sometimes the clamps that hold the flex hose rust and constrict the flow I just loosen the clamp on the hose and usually it fixes it.