Front brakes not releasing

B

Boats90GT

Member

Jun 10, 2026

4

1

13

FL

Tuesday at 2:03 PM

#1

• Tuesday at 2:03 PM

• #1

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

 

Last edited: Tuesday at 3:30 PM

nickyb

I gotta say i never painted my nuts, Never Ever

15 Year Member

Apr 3, 2009

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nevada

Tuesday at 2:18 PM

#2

• Tuesday at 2:18 PM

• #2

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

 

B

Boats90GT

Member

Jun 10, 2026

4

1

13

FL

Tuesday at 3:28 PM

#3

• Tuesday at 3:28 PM

• #3

nickyb said:

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

Click to expand...

flow was good no issues.

 

rednotch

I'd like to remain having one chocolate starfish

Founding Member

Aug 14, 2000

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south jersey

Tuesday at 4:01 PM

#4

• Tuesday at 4:01 PM

• #4

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

 

Last edited: Tuesday at 9:13 PM

Reactions: Shakerhood and AeroCoupe

FastDriver

I was uncomfortably high & wearing a helmet

SN Certified Technician

Sep 5, 2001

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Vass, NC

Tuesday at 11:19 PM

#5

• Tuesday at 11:19 PM

• #5

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

 

nickyb

I gotta say i never painted my nuts, Never Ever

15 Year Member

Apr 3, 2009

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nevada

Yesterday at 10:38 AM

#6

• Yesterday at 10:38 AM

• #6

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

 

Qtrhrse23

Active Member

Jul 2, 2024

72

28

28

Texas

Yesterday at 4:33 PM

#7

• Yesterday at 4:33 PM

• #7

Calipers.

 

rednotch

I'd like to remain having one chocolate starfish

Founding Member

Aug 14, 2000

1,428

654

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south jersey

Yesterday at 6:53 PM

#8

• Yesterday at 6:53 PM

• #8

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

I was uncomfortably high & wearing a helmet

SN Certified Technician

Sep 5, 2001

6,134

2,759

224

Vass, NC

Yesterday at 7:47 PM

#9

• Yesterday at 7:47 PM

• #9

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

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

Founding Member

Oct 28, 2001

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Claremore, OK

Yesterday at 9:20 PM

#10

• Yesterday at 9:20 PM

• #10

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.