# Car off, brake pedal doesn't pressurize from pumping it??



## EnIgMa '06 (May 13, 2004)

Hey everyone. I drive a 1992 Corrado SLC. I have stock sized brakes all around with new front calipers, new MKIV aluminum rear calipers, all 6 stainless steel lines, newer rotors, new Hawk HPS pads and new Super Blue brake fluid. After installing all of this I bled the lines with my pressure bleeder (I bled an entire bottle of Super Blue through). After bedding in the pads, the pedal felt better, but the first bit of travel didn't feel so great (it stopped amazingly well, but it felt a little soft).
So today I bled the master cylinder and slave cylinder (something that I don't think has ever been done to my car before). I bled each several times to make sure I got all the air out (master first, then slave). For all bleeding I followed the procedure in the Bentley manual.
I still have a weird feeling pedal. When the car is off and I pump the brakes, the pedal doesn't get stiff like it does in all the other cars I've driven (most recently a Boxster S, so maybe I'm just not being fair to my VW).
Is this the sign of a greater underlying problem?
Also, I've had an ABS light on for like 3 years. I don't really pay attention to it as when I hook it up to VAG-COM it never tells me that anything is wrong.


_Modified by EnIgMa '06 at 4:42 PM 5-8-2009_


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## EnIgMa '06 (May 13, 2004)

*Re: Car off, brake pedal doesn't pressurize from pumping it?? (EnIgMa '06)*

Bump


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## spitpilot (Feb 14, 2000)

*Re: Car off, brake pedal doesn't pressurize from pumping it?? (EnIgMa '06)*

If you have bled system to be sure there is no air in it, and you see no external leaks..but you still have very soft pedal then I'd suspect the MC seals..they can fail and let fluid go back into the tank instead of fully pressurizing the brakes....if the last seal fails you can even fill your booster with fluid!







All will look good from the outside...nothing leaking anywhere and still the system won't be able to develope full braking power!


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## ECS 1.8T (Jun 23, 2008)

*Re: Car off, brake pedal doesn't pressurize from pumping it?? (spitpilot)*


_Quote, originally posted by *spitpilot* »_If you have bled system to be sure there is no air in it, and you see no external leaks..but you still have very soft pedal then I'd suspect the MC seals..they can fail and let fluid go back into the tank instead of fully pressurizing the brakes....if the last seal fails you can even fill your booster with fluid!







All will look good from the outside...nothing leaking anywhere and still the system won't be able to develope full braking power!









x 2
if there is fluid in the booster, it'll eat away at the diaphram inside.


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## EnIgMa '06 (May 13, 2004)

*Re: Car off, brake pedal doesn't pressurize from pumping it?? (ECS 1.8T)*

This would be fail. So basically if I rebleed and still have this problem (I assume the pedal not pressurizing when the car is off _is_ a problem?), then I should basically assume my master is bad?
I hate my car.


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## spitpilot (Feb 14, 2000)

*Re: Car off, brake pedal doesn't pressurize from pumping it?? (EnIgMa '06)*

Whether the engine is off or on..you should get rock hard pedal if all seals and lines are OK..if the pedal sinks to the floor either slow or fast then you have a leak of the hydraulic pressure needed for braking power. If your pedal is soft and you can find no leak from wheel caliper seals, hoses, lines or fittings..no fluid visible leaking anywhere..then leak's gotta be internal to MC...the seals in the MC are supposed to seal off the access to the tank and build pressure in the lines and they are not doing it..either fluid is bypassin 'em back to the tank or bypassing the last seal in the cylinder and running into the booster..either way its new MC time!








PS: If you let system go unmaintained for years and years..no system fluid flush...then change a leaking caliper or decide to go to SS brake lines say...and you bleed the heck outa the system you can ruin your MC seals in the process of bleeding..if you do any pump bleeds (like the Bentley reccomends even after pressure bleeding) you can run the MC seals across areas in the cylinder bore where they don't go in normal system operation...and in those areas is a bunch of crud from not having flushed system like you should..that crud can ruin the seal lips and cause MC failure!
























_Modified by spitpilot at 7:48 PM 5-10-2009_


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## EnIgMa '06 (May 13, 2004)

*Re: Car off, brake pedal doesn't pressurize from pumping it?? (spitpilot)*

Superb. I'll do a pump bleed but otherwise I'll start saving.


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