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Did I damage my master cylinder?

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Old Jun 29, 2011 | 07:17 AM
  #11  
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Yes, the first few pumps were to the floor then I pumped some more but didn't go to the floor, maybe a couple more times over subsequent attempts to firm up the brakes and release the piston. I have little to no resistance now with the car on.

I'm hopeful the bleeder arriving in a few hours will solve this. If not, I'll try to find someone with a VAG-COM (already put out a post in the midwest forum) or I may possibly buy one but it's really low on my list of "wants" right now (have a baby coming in the next few weeks and this brake job is getting exponentially more costly).

I may see if my buddy can convince a mechanic shop owner he knows to lend me his vag-com tool for a day (or rent it). Anyone ever have luck renting one from a shop?
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Old Jul 1, 2011 | 02:10 PM
  #12  
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Originally Posted by Just Me
when i do my brakes, the first couple of pedal pumps go to the floor as the pistons adjust. Then all is well.Have you doen that?
So I have another update... I was able to bleed my brakes of a TON of air with the motive bleeder and my car actually had enough resistance for me to actually stop. So here's what's happening now (add link to a thread of this has happened already to someone please):

When I have the car off, I can pump the brakes and get them back to normal resistance. When I turn the car on, I pump it lightly two times and my pedal firms up a lot. Then my next push I push slower and further and the pedal keeps giving way and eventually it'll hit the floor, or as far as it normally travels when the car is on. I then can try another slow but steady push and it'll do the same. I then can pump the brakes twice lightly and get my pedal pressure back but as soon as I push down again, it slowly sinks to the floor. If I hit the brakes harder, it'll give me resistance halfway down like it should but not as soon as I normally get it and also the car doesn't stop as well as it should. When I was doing my bedding-in run, I had to push the pedal close to the floor everytime to get the car to slow down and especially to stop at a stop sign (more like a california roll).

I'm not sure what to make of all this. My brakes should be cool now, I'll go try it again and see if it's doing the same thing.

Last but not least, I have no brake fluid leaks in my system, (at least that are leaking brake fluid) and my master cylinder seems to hold pressure just fine, at least up to 12psi when I had the bleeder hooked up to it.

I'm out of ideas now. I used two quarts of brake fluid pushing all the air out of the system and basically flushing the old fluid. I also used a rubber mallet and banged on the caliper a bunch to loosen up the air bubbles (this worked amazingly well).

I guess it's possible I could have banged something out of alignment or something but I find that hard to believe as all lug nuts are torqued properly and the rotors spun freely when I had the car on blocks.

Last edited by wibs; Jul 1, 2011 at 02:15 PM.
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Old Jul 6, 2011 | 08:11 AM
  #13  
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sounds like you have a leak?
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Old Aug 30, 2011 | 04:39 AM
  #14  
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Did you ever get it fixed? What was the problem?

I'm trying to troubleshoot a soft brake pedal.
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