[jhines_06gli]

Dealing with a 2005 545i, when braking at slower speeds(below 45). You can apply the brakes "Normally" with regular pressure and vehicle will begin to slow down, then pedal gets ROCK HARD and feels like you are gliding to a stop. I checked the brake fluid and it was a nasty ruby-color and smelled like burnt trans. fluid.......thoroughly flushed systema dn will have to do again this weekend as some circulated through while activating ABS.
But anyways, seems like there is an issue with the brake assistance or the booster or something. Just wanting some input and to see if anyone has had this issue before. The vacuum pump driven by the camshaft is working and producing 30"HG, and both the large and small lines coming from it seem OK. Pulled the plug out of the booster and there is no fluid or water in the booster. Just new to the whole BMW side and not sure how that dual-stage brake booster works and all.
Car is not all that safe driving in traffic because when stopping, almost have to stand on pedal to bring the car to a quick stop. Also, brakes were all replaced when I bought the car and do not seem glazed, but I'm sure they are not OEm.....a next step is to tray and hone the brake discs and resurface the pads, see if that helps. But seem almost certain it is something to do with the booster or the assist.
Thanks in advance guys, still learning the BMW side(a lot diff. from VW/Audi that I am used to)
-J. Hines

 

[witeshark]

As important as the obvious safety issues are, you may well wanna consider having a brake shop or dealer service the brakes ASAP.

 

[BimmerE39]

You mention that your brake fluid looks strange. Do you happen to know what type of fluid it is by any chance?

 

[jhines_06gli]

I do work for a delaership, just not BMW.....work for VW. I know the brakes are OK, pads are a little harder than stock Euro pads usually are. But the rotors are not glazed really and show minimal heat damage.

The fluid was a ruby-red color. I called a friend who is a service writer at BMW here in town and he said that should be DOT4 fluid. Even the race fluids you see are usually blue. But by no means was the previous 70-year-old man who bought this car new in need of "race" fluid.

Not really sure at this point. Think I will conitue to flush the system til it is the nice yellow-clear color of standard DOT4 and go ahead and dissasemble the brakes and rotors and scuff down pads and hit the rotors with a disc-hone. I'm out of ideas past that point other than internal issue with booster??
-J. Hines

 

[BimmerE39]

Your situation seems very odd. If I were you I would flush the fluid with Ate Super Blue or something similar.

 

[jhines_06gli]

So yea........brake fluid is pretty clear now, all pads are good and filed down glazing just to be sure. Re-honed rotors and checked everything out.....all seems OK. My contact at BMW is saying that the dual-stage booster has gone out. I am new to this BMW parts thing, so who are some good vendors that would have anything/everything for BMW. I have had ZERO luck finding this part outside dealer so far.

And he said that by part #, the local dealer has installed 20 of this exact one alone!! Common issue?
-J. Hines

 

[BimmerE39]

Bavarian Autosport generally has that kind of stuff. Search by the part number and see if you can find it.

 

[jhines_06gli]

Looks like it will be a dealer-bought item unless my last resort has it.....we'll find out tomorrow morning. Otherwise it's a little over $500 and a few hours my time....oh well.
-J. Hines

 

[BimmerE39]

Good luck with the repair!