I am having a brake problem where the brakes stay locked or engaged after pressing them hard. All four wheels will be engaged.

To release them, you either have to pop the bleeder on one of the front wheels or you can depressurize the booster.

Bad Booster? Or Master Cylinder?

This is a CMC race car, so I don't have ABS and the front brakes are upgraded to LS1 calipers and rotors.

Thanks,

James

 

Can one collapsed brake line cause this?

 

The front lines are brand new braided lines. The rears are stock rubber.

 

how did you completely remove the abs or just disable it?
how do you depressurize the booster?

 

This is a race car, so I just removed the ABS unit and rebuilt brake lines.

Depressurizing the booster by simply pulling the vacuum hose out of the booster itself....and vacuum pressure will be released.

 

i'm pretty sure the brake booster hose connects to the check valve on the booster, and the check valve prevents the booster from getting depressurized

at least thats the way it is on my 3rd gen, havent really checked my 4th gen
thats why it doesnt really make sense to depressurize it by removing the hose, it should still hold its vacuum

are you doing this while the engine is running or not?
if you do this while the engine is running, do the brake release when you shut off the engine?

 

I can pull the valve out of the booster with the engine hot or cold, or engine running or not.....and it doesn't matter. Once the vacuum is released out of the booster....the brakes will release and not until the vacuum is released will the brakes release.

They will not release even if sat over night as long as the booster is still holding vacuum.

I am thinking is just about has to be the booster and will probably change it out this weekend to see, but I was curious if anyone else had had this problem.

 

if your pulling out the boosters check valve then yes i would say the fault is in the booster