# brake still spongy after mc change and lots of bleeding



## clean (Dec 18, 2002)

so my girlfriend has a 98 cabrio and her brakes have been "spongy" for awhile. basically it's fred flinstone style w/ her brakes. so i go and bleed them, nothing. bleed again and again, nothing. so i assume its the master cylinder, go get a brand new one, bench bleed it then go through and bleed every calpier, nothing same damm thing. whats with the brakes? what else could be wrong? i looked at all the lines and there are no leaks, what gives? someone help me her sticker is over a year expired and I GOT A TICKET DRIVING HER CAR COSTING ME $135, so please any help would be appreciated.


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## clean (Dec 18, 2002)

*Re: brake still spongy after mc change and lots of bleeding (clean)*

anybody have an idea? I have searched on here and found nothing, i'm surprised there is even a brake forum.


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## Banditt007 (Oct 23, 2002)

*Re: brake still spongy after mc change and lots of bleeding (clean)*

make sure there arent any leaks anywhere...check all the brake line connections and lift up the dust boots on the calipers and check for leaks. there may be air still trapped in the system. if the bleeder screws do not point straight up, try bleeding them with them facing straight up (remove from carrier, and place a block of wood so the piston dosent go flying out of the caliper) and tap them w/ a wrench to 'un cling' air bubbles. tapping on the hardlines as well may work and loosen the bubbles so they can be released. possibly air trapped in the abs system? i'm unsure how that system works on the mk3 so i cannot comment, but i do know its common to have that happen on the mkiv if the reservour is sucked dry. and air gets in the abs unit.
how did this problem happen, just one day the brake pedal went mushy or after replacing a caliper/brake line type thing?


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## clean (Dec 18, 2002)

*Re: brake still spongy after mc change and lots of bleeding (Banditt007)*

she doesn't have abs. Im not sure how it happened, it's been this way since weve been together, just a couple months. her old boyfriend used to work on her cars. checked for leaks in all the lines the fluid would have to go somewhere like the garage floor right? could the calipers be bad?


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## Horus (Sep 28, 2005)

*Re: brake still spongy after mc change and lots of bleeding (clean)*

i had the same problem...for years...could never have figured it out..i had half the pedal dead.. so this could really help.


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## disphunktion (May 18, 2002)

*Re: brake still spongy after mc change and lots of bleeding (Horus)*

Back to the alive thread.
I have the same situation. New Master Cylinder which has been bench pressed, new lines, new calipers and did too many bleeding with a friend and it's still spongy.
Everything is new and there is no leak.
One thing which is weird, is when I try vacuum bleeding 
(with the Motive pump) and open the valve there is nothing coming out in the back caliper but when it's by "pumping" and opening/closing the bleeder there is tons of fluid coming out.


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## jetta coupe (Mar 30, 2009)

*Re: brake still spongy after mc change and lots of bleeding (disphunktion)*

friend of mine had the same problem. he changed to rear disc with drum proportioning valve and he says problem solved


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## aceperry (Aug 2, 2006)

*Re: brake still spongy after mc change and lots of bleeding (jetta coupe)*


_Quote, originally posted by *jetta coupe* »_friend of mine had the same problem. he changed to rear disc with drum proportioning valve and he says problem solved

That's a ridiculous solution. I have the same prob as disphunktion, where the rear doesn't bleed unless you pump the brake pedal. There has to be a better way. Anyone?


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## jetta coupe (Mar 30, 2009)

*Re: brake still spongy after mc change and lots of bleeding (aceperry)*

i do agree with you.that is just what he told me he did to fix his problem. my wife has a 96 that we have had for 4 yrs, with the same problem. another friend has a 86 with the same problem, turned out to be proportioning valve.


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## aceperry (Aug 2, 2006)

With some cars, like my B4 Passat, there is no mechanical proportioning valve. That function is done in the ABS unit and is controlled electronically by the ABS controller.


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## clean (Dec 18, 2002)

*Re: brake still spongy after mc change and lots of bleeding (disphunktion)*

it ended up not being the master after all. after looking at the calipers themselves i noticed the piston wasn't moving and had rusted itself in the caliper. so a little heat and a wack of a bfh and i solved the problem. she got a new master cylinder out of it. good luck


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