Anyone have any results on changing the booster? How did it feel before? and How does it feel now?
I've got about 3-4 cars that have the squishy pedal on track feeling. They all have BBK or newly rebuilt stock brakes. Several have new Masters cylinders as well.
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Does anyone have a part # or vendor they recommend for the booster? I looked on www.realoem.com and couldn't seem to find it.
I have flushed and bled my brakes over and over. Even had James at RRT flush the ABS with the Autologic computer. Still had a soft mushy feeling pedal. Wonger says the booster will fix it. I hope to find out for sure.
I have my new booster in hand. I might be able to start on it tomorrow but I may not have time to finish it. I hope to have it done for a track day on the 15th.
Done! I was able to work on it today and got it finished!
Replacing the brake booster has made a huge difference in the feel of the brake pedal! It's now firm and predictable, not mushy and vague like it was before. I'm a believer.
I completely removed the master cylinder and ABS unit together, I only had to undo the clutch feed line and the four lines coming out of the ABS unit. Then I was able to carefully coax the master cylinder and ABS unit out without having to separate them. With everything out of the way the booster was easy to get out. Under the dash was simple, remove the clip, pin and spring from the pedal and remove the four nuts holding the booster to the firewall.
I bled all four corners and got lots of bubbles. I think there still might be a little air in there but I ran out of fluid. I hope to get James at RRT to flush the ABS with the Autologic again and do another full bleed.
Look ma, no brakes!
The Culprit.
Part number.
New and old. You can see there is no adjustment on the clevis.
Master cylinder and ABS unit.
All done!
Wow. I bought a used master cylinder out of a m3 with 40k on it and hasnt been sitting a while. Im gonna throw that in and if I still have the low pedal, booster here I come. How long did it take you to do the whole job and how much of a pia was it?
Cant wait to hear the results after you are 100% done with the bleeding, etc.
It took me about five hours total. It wasn't too bad, I took my time and didn't try to force anything.
I'll bleed the clutch when flushing the ABS. I'm looking forward to the final results also.
All fixed. The brakes rock now. Replacing the booster was worth every penny and every bit of work.
Shit lol. Worst case I have to get a booster. Im probabaly just going to be getting a used one, mostlikely the one I am getting the master cylinder off of. It only had 40k on it and it hasent been sitting long, said the brakes were rock solid. Im gonna take my chances. Im replacing the master tommorrow. If it is still crap then I guess we have very conclusive evidence that the booster really is the problem area. Ill update tommorrow.
Welp guys, I just replaced my master cylinder today and the brakes feel a heck of a lot better. The pedal is still a little low but the mushiness is gone and it doesnt seem like you need to apply as much pressure anymore. I am going to pressure bleed the system since I got the abs to kick in a few times and then report back, but so far so good. Fingers crossed
After a few days with the new master, the pedal still doesnt feel like its on par with a friend of mine's pedal in his m3. It still feels a little vague and that it needs a decent amount of weight to get the brakes to stop. It also seems like only my driver side abs kicks in. Its hard to tell but it seems that way. So just to reinterate, are these symptoms similar to people's problems who changed the booster and corrected the issue?
I plan on throwing it in either way but it will help me sleep at night at least if the booster really did fix the issue.
Hey if the booster was as easy as the mc was to replace I would have done that first. I bought a used master cylinder for a reason haha. Im just going to buy the used booster from the same m3 I got the mc from (40k miles on it and hasent been sitting long) Ill have the booster by tuesday so tuesday night will be a long night im guessing. Im going to need some more superblu as well. Just one other thing... I havent bled the clutch line since the intial bleed after replacing it with a ss line. Should I be bleed it again after this? Im sure it will help some but it ultimately only creates a bit of a mushy feeling in the brake pedal correct? I no longer seem to have that, it just has a long pedal travel and takes a lot of effort to really get the brakes to work. Thanks for everything guys, definately be reporting back with my results.
Bleeding the clutch won't do a thing for your brakes. The only thing the clutch and brake hydraulics share is a common fluid reservoir. And that reservoir is divided internally with plastic baffles such that you could could use tin snips to sever your clutch line and still not lose your brakes.
It's a good idea, for the health of your clutch slave and clutch master cylinders, to bleed the clutch every couple years with the 7mm bleed screw on your slave cylinder. But it's not going to do anything to address the problems you've described in this thread.
Dave Zeckhausen
Yea i didnt think it would but people say every now and then that you get an air bubble here and there that could have contributed to the issue. I just did the clutch this time last year with a new slave and clutch line so I dont think I have an issue. Cant wait to replace the booster and give you my conclusions.
Ok guys another crappy pedal solved. Rack another point up for bad booster. My brakes are amazing now, feels like a new car
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