sticking brakes

[monacochris]

I've got a 68 monaco, 4 wheel drum brake. Replaced master cylinder, brake lines and wheel cylinders. Took brake booster off cleaned and painted it. Now when i drive car and push brake pedal it sticks down and i have to pull up with foot to release it. I'm leaning towards bad brake booster. Wondering if that is the place to start checking. With engine off pedal works fine.

 

[CBODY67]

There is a valve in the booster that might be having a problem. Not sure why it happened after the removal and cleaning, though.

Typically, with your foot lightly depressing the pedal, when you start the engine, you should feel the pedal move down slightly and take less pressure to keep applied. In the past, there were rebuild kits you could buy, but they might take some special tools to separate the booster halves and put them back together. You might keep playing with it and see if it acts like it wants to operate correctly.

Otherwise, a reman booster might be the best option (with a product warranty!). Keep us posted.

CBODY67

 

[traintech55]

Replace, or rebuild the booster. I had the same thing happen 44 years ago and wrecked the car because of it.

 

[Davea Lux]

I've got a 68 monaco, 4 wheel drum brake. Replaced master cylinder, brake lines and wheel cylinders. Took brake booster off cleaned and painted it. Now when i drive car and push brake pedal it sticks down and i have to pull up with foot to release it. I'm leaning towards bad brake booster. Wondering if that is the place to start checking. With engine off pedal works fine.

It sounds like the rubber internals of the booster have gone south. If you had a leaking master cylinder, that probably was the cause. Brake fluid degrades the rubber parts in the booster and usually a big internal vacuum leak is the result. It is time to rebuild the booster. If you have an original vacuum hose to the booster, be sure to replace that as well with a new vacuum rated hose.

Dave

 

[LocuMob]

Check the master cylinder as well. I had that symptom when I got my car and the single pot master failed mot long after. Still have the same booster,and with a loose fitting check valve, it has plenty of power assist.

 

[monacochris]

Thanks for input. It will give me a starting point. Car is stored now for winter, so will pick at it over coming months.