Brake pedal stays down won't fully return

[toomanycars]

I'm working on the 73 Cuda and the Brake pedal stays partially down and won't fully return. The brakes work great and the pedal is solid but I have to pull the pedal up the last inch or so for the brakes to release otherwise the wheels stay locked. I've tried 2 master cylinders and tried adjusting the push rod but no luck. The car has new hoses calipers and pads. The only thing I haven't changed is the vac booster but I did try it with the vac line disconnected and it didn;t make a difference. Any thoughts or suggestions would be appreciated.

 

[cuda joe]

I looked underneath the dash and saw the brake pedal arm contact the brake light switch and i can still pull it the pedal back about an inch ..and i don;t have a problem with the brakes locking up have you tried making the rod shorter ? mine is a manual front disc brakes

 

[toomanycars]

Yes I did try shortening it, I had it back about 1/4 inch but they still lock. I'm going to pull the booster I guess, I never had to mess with those before.

 

[cuda joe]

it sounds like a weird problem ..do you have a disc brak mc one large one small resavoir ?

 

[toomanycars]

Yes it is, everything lined up with the one removed. The only other part I haven't replaced is the proportioning valve.

 

[cuda joe]

I would pull the booster too i don;t think a proportioning valve would do that. good luck

 

[Quiny]

Are the rear brakes drum or have they been converted to disc? Also did they used to be OK or did this problem just start, was any work done before it happened? If they are drum brakes there is a check valve incorporated into the master cylinder. If you have calipers you don't want that check valve there. There is also the possibility that you have a master cylinder for a 4 wheel drum brake setup. Good luck, strange problem.

 

[toomanycars]

It is an original disk front and drum back car. The car had been sitting for many years and the brakes didn't work so I did lines, calipers, pads, master and rear cylinders. The master has a large and small reservoir so it should be good.
Maybe I need to hit it with "Illudium PU-36. (only you will get that)

 

[Quiny]

It is an original disk front and drum back car. The car had been sitting for many years and the brakes didn't work so I did lines, calipers, pads, master and rear cylinders. The master has a large and small reservoir so it should be good.
Maybe I need to hit it with "Illudium PU-36. (only you will get that)

I dont think an explosive space modulator will help

 

[toomanycars]

Seems like the best option most days.

 

[Quiny]

Seems like the best option most days.

Another thing to try that is free is to remove the vacuum check valve, as well as hold vacuum in the booster when the engine stalls it also allows relieves excess vacuum to equalize both sides of the diaphragm when the pedal is released. It could be slow.

 

[cuda joe]

is it the front or rear wheels locking up or both ?

 

[cuda joe]

when you put in the new brake lines could the back and front lines be switched on the mc stuff happens once i connected the fuel line to the carb vent took awile to figure out why it flooded all over the place

 

[340 Slapstick]

I had an old Panhead Harley (don't stop reading) and the rear brake was locking up. turned out to be the brake hose was deteriorated and not flowing correctly. I replaced the brake hose and that fixed it. Just from what I read here, and I may have missed something)-maybe your brakes can be depressed but not enough pressure to bring the fluid back so the pedal stays down.

 

[toomanycars]

Thanks for all the advise! I think I got it. I pulled the booster and master, went over all the moving parts for the pedal and now it's coming back up like it should. Must have been binding somewhere.

 

[cuda joe]

great I;m happy you got it .like your name thats what my wife says