# Help! Brake Pedal "Sticks" and does NOT return Up!!!



## Katmandu (May 26, 2004)

I just picked up an 81 Rabbit Diesel that had been sitting for about (2) years.
It had a broke RR brake line when I bought it and I just repaired it and cleaned up the rear brakes (appeared fine). The fronts looked OK as well. I bled the brake lines out as well. The brake pedal feels good and firm (when the car is off).
Anyways, the brake pedal STICKS in the down position (Not to the floor) *while the engine is running*. I have to stick my toe under the pedal to pull it back up into position and release the brakes.








When the engine is off, the brake pedal feels normal and comes right back up to position. ???
What's going on here ??


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## phatvw (Aug 29, 2001)

*Re: Help! Brake Pedal "Sticks" and does NOT return Up!!! (Katmandu)*

I think that symptom indicates a bad master cylinder or vacuum brake booster or perhaps both?


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## Katmandu (May 26, 2004)

*Re: Help! Brake Pedal "Sticks" and does NOT return Up!!! (phatvw)*

Here's a reply I received elsewhere....

_Quote »_The vacuum brake booster between the pedal and the master cylinder may be sticking. Remove the master cylinder from the booster and check for brake fluid leaks into the vacuum booster that could gum up the booster causing sticking. 
If there are no fluid leaks, and the pedal will return to the proper position after turning off the engine and pumping the pedal several times, then the vacuum system in the booster may be stuck, always applying full boost to the pedal rod preventing it from fully returning. There may be a stuck vacuum check valve in the booster that can be cleaned or replaced. 



_Quote, originally posted by *phatvw* »_I think that symptom indicates a bad master cylinder or vacuum brake booster or perhaps both?


Roger that.
How does one diagnose either of those ??










_Modified by Katmandu at 10:16 AM 5-2-2006_


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## phatvw (Aug 29, 2001)

*Re: Help! Brake Pedal "Sticks" and does NOT return Up!!! (Katmandu)*

On the intake manifold, there should be a vacuum hose going to a big drum-shaped thing near the brake fluid reservior. It shoudl look different than other hoses because it shold have a lump (check valve) in-line. The other vacuum hoses will just be flat. Try disconnecting that hose and see if the symptoms change.
The brake pedal should be much harder to push in because now you don't have power brakes, but if the vacuum booster is indeed busted, it shouldn't stick any more.


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