# Brakes and Vacuum pump..Please Help??



## jnesbitt (Dec 24, 2009)

I have a killer brake issue..on my 83 Rabbit 1.6 turbo diesel.I have replaced my rear brakes, bleed after bleed after bleed..all new hard ware and lines on the rear and new Master I still have the same problem I started with before replaceding anything. I'm able to pump the peddal and it holds firm, as soon as I start the car the peddal goes slowlly to the floor and I have to pump to get it firm again..but it doent stay firm. Also when I pump I hear a swish swish sound coming from the peddle. I am certain there is no air in the lines and I may have a bad vaccum pump or seal..or possible bad booster..any deas on how to test or know if I have a bad or leaking vacuum pump. The peddal has no pressure at all and my front brakes lock up if I give normal pressure, it real bad if I have to hit them hard.


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## shelby987 (Dec 16, 2009)

I have had a similar problem, bleed after bleed left me with a firm pedal for a min.....then to the floor. I traced it yesterday to the rear brake pressure regulator valve, it looks kinda like a wheel cylinder with 4 brake ports in it. The section that has the rubber cap has a plunger attached to the rear suspension, it was sucking in air when I hit the brakes and negating my bleed of the system. My new valve in already in the mail....might be the source of your problem too.


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## jnesbitt (Dec 24, 2009)

*Re: (shelby987)*

Thank you..Please let me know if this works for you..it a $100 part and the next step in my trouble shooting..I have replaced everything..let me know if this does the trick. Funny thing is I pulled the valve and ran the line directly to the MC and it still did the same thing...


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## shelby987 (Dec 16, 2009)

The short answer is the valve was replaced tonight, and I believe it was part of the problem......but it was not the solution. I don't want to hijack your thread....so I started my own. I will update yours when I find a solution.


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## jnesbitt (Dec 24, 2009)

*Re: (shelby987)*

ok took her to two shops first guy VW guy couldnt figure it out..put new master clyder in her...same problems. I took it to another shop and put new pads and clipers in her..they said the master was bad and also the brake booster..leaking fluid between the two. The probem is fixed and the brakes work great now.


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