Front brakes not releasing

Boats90GT · Sep 15, 2026

1990 GT, Front brakes (both) not fully releasing . Car had the issue when I bought it so threw money at it with new hoses, calipers and pads, inspected and repacked bearings. Still not releasing fully. Car came with Wilwood proportioning valve so the factory one is long gone. Would like to remove that and put back OEM one but anyway. Anyone know what else I can check? Also just realized when I start the car they release but when I hit the brakes with car still running they don't fully release, Kind of doesn't make any sense. Thanks

nickyb · Sep 15, 2026

When you bleed the calipers how was the flow? Could be kinked/clogged line.

Boats90GT · Sep 15, 2026

nickyb said:
When you bleed the calipers how was the flow? Could be kinked/clogged line.

flow was good no issues.

rednotch · Sep 15, 2026

What master and booster? The push rod probably needs adjustment if nothing else is causing it to hold pressure.

FastDriver · Sep 15, 2026

Bad booster or caliper? Both sides binding? Doesn't have a line lock, does it?

nickyb · Sep 16, 2026

Also check that the calipers slide on the pins freely,they maybe hanging up

Qtrhrse23 · Sep 16, 2026

Calipers.

rednotch · Sep 16, 2026

Both sides means sometimes holding the pressure, only thing he didn't swap was the master and booster... Doubt its the prop valve since everyone mounts those for the rear bias... Either booster rod too far out or MC psiton seals messed up one of them isn't allowing it to fully release.

FastDriver · Sep 16, 2026

Yep. Why I asked about the booster first. When the booster is compromised, it can build a vacuum that brakes the front. With engine shut off, that goes away. This was a year-long painful issue to work through with a brand new LMR 93 Cobra booster.

AeroCoupe · Sep 16, 2026

Went back and read the fist post and the OP said the factory proportioning valve is gone. With that I am gonna have to ask the OP an important question...what do you mean by the facoty proportioning valve is gone? Did the previous owner remove it from the factory combination valve and and leave the rest of it intact such that you have factory plumbing or did they remove the combination valve completely and all you have is a manual proportioning valve for the rear brakes and some custom plumbing?

For reference this is the factory combination valve with instructions on what to remove to delete the proportioning valve side of it.

Boats90GT · Oct 25, 2026

AeroCoupe said:
Went back and read the fist post and the OP said the factory proportioning valve is gone. With that I am gonna have to ask the OP an important question...what do you mean by the facoty proportioning valve is gone? Did the previous owner remove it from the factory combination valve and and leave the rest of it intact such that you have factory plumbing or did they remove the combination valve completely and all you have is a manual proportioning valve for the rear brakes and some custom plumbing?

For reference this is the factory combination valve with instructions on what to remove to delete the proportioning valve side of it.

Factory proportioning valve is no longer in the car. There is an adjustable one installed I gues for the rear drums. UPDATE. No better off than I was a month ago. The booster and MC look pretty new to me. I am pretty sure they just installed the stuff and didnt make the necessary adjustments to the rod. I feel to do it correctly I need to remove booster and MC and measure it on a workbench.

Front brakes not releasing

Boats90GT

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nickyb

I gotta say i never painted my nuts, Never Ever

Boats90GT

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rednotch

I'd like to remain having one chocolate starfish

FastDriver

I was uncomfortably high & wearing a helmet

nickyb

I gotta say i never painted my nuts, Never Ever

Qtrhrse23

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rednotch

I'd like to remain having one chocolate starfish

FastDriver

I was uncomfortably high & wearing a helmet

AeroCoupe

lube between the nut and the face. I know my lubes

Boats90GT

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