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Yeah, weird ABS airlock issues are fun.

I had to flush the brakes in the 993TT with alcohol to fix an ABS sludge issue. It's the last ditch thing before you spend enough money to buy a whole E53 to get the ABS pump rebuilt. Fortunately it worked, even if it was a damned weird feeling.

My 2 cents --- Aside from air being trapped in the ABS system which requires the pump to be activated, there are often high spots in the system (eg. front brake hoses) that require a good flow to get get the air flushed out (8 PSI is not going to do it) and having a second person on the pedal is the best way to get that. Air trapped in and just below the master can require some patience to let air bubble up through the compensating port. Vacuum bleeders will draw air from around the bleed screw so there is no way to tell if/when fluid is clear. They are nice for brake flushing though.

Quote:

Originally Posted by Effduration (Post 1224965)

I think the only way to bleed these cars after opening the system is use a pressure bleeder AND run the ABS Bleed procedure with INPA or some other 2nd level scanner.

for a simple brake fluid flush, you can get by with just a pressure bleeder, but anything more you have to activate the ABS bleed routine with a scanner.

The worst part of it all was that two shops (both German auto repair facilities) attempted and neither were successful.. The first guy I've known so long he felt bad enough to not charge me anything. I'm not sure what kept me thinking it was air but I think I'm finally winning the war! Pedal's at about 90 % +\- at the moment and I think an additional bleed, this weekend, should have me back to 100%.

Quote:

Originally Posted by workingonit (Post 1224967)

We tried a combination of pressure bleeding with ABS bleeding (via Foxwell), drip bleeding with Foxwell, and using vacuum at the bleeders, again with the Foxwell ABS bleeding program. Couldn't tell much difference between the three methods.

My Motive Power unit wasn't as good as I thought it should be, since I could never get over 8-10 psi (I had a different brand years back that'd give twice that). Drip method (just adding to the MC as it was needed) was useless while the ABS program was running, and the Pittsburg (Harbor Freight) vacuum bleeder drew lotsa bubbles out, but never clear fluid on the last bleeder.

I hope a professional shop will have the right equipment, the personnel needed, and the honesty to fix it cheaply, without firing a parts cannon at it. But my wife says "get 'r done" regardless. Oh well.

The irony is that two repair shops had attempted it as well, I screwed up the flare fitting on one of my lines which is what caused it to go to shop 1 in the first place, once we got it all back together - and keep in mind I've done brake work to this car a half dozen times in my ownership - it wouldn't bleed, no matter what was tried, pedal never improved.

That resulted in it going to shop 2 - my mistake, I should have just taken it home then - because there was the suspicion of it being a "larger problem" than maybe just bleeding. Shop to worked their magic, said everything was sound, sealed and ready for bleeding... and after numerous attempts, couldn't get the pedal to improve anymore than feeling really great at just less than the last inch of travel.

That's when I brought it home and finally just put in the energy to run fluid through it until I got a pedal - don't get me wrong, it felt like insanity, but as I noted in post 1, there were micro bubbles and my wife confirmed that I wasn't crazy - at least at that moment :rofl:

I think what helped me the most was stopping and activating each circuit independently in the ABS menu as I bled that circuit. If yours isn't fixed yet, I wish you all the best of luck, I know how frustrating it can be!!

Quote:

Originally Posted by andrewwynn (Post 1224972)

There are two distinct bleed procedures you need to do with the scanner. I only saw the one mentioned.

Hi AW, please, please let me know what I've missed, maybe that's the last 10% I don't seem to be able to get?

Ran the ABS, also ran the individual ABS circuits as I bled that circuit, that's all I've ever needed to do in the past, would LOVE to know what I'm missing so that I don't do that it again - stupid hurts! (and takes up way too much time :bustingup)

Thanks!!

Quote:

Originally Posted by noodlesandsam (Post 1224977)

I have a 2005 mini r53. It had a rusted thru rear brake line - I replaced it, and the Master. I used the motive pressure bleeder, and I had the car running when I bled. The rears were uneventful, but the left front caliper blew an amazing amount of air from the bleed valve. Pedal feel after that has been fine.

Heard that!! I could have dried my hair (I don't have much) with all the air that came out of my lines when I had the privilege of discovering they rust out right under the driver side floorboard... So with that said, I guess I've had two "Oh shit" moments with this car - DOH :D

Quote:

Originally Posted by nick325xit 5spd (Post 1224985)

See, I am almost to that point, I say micro bubbles, but something in the back of my mind said "sediment" of some kind, that "stuff" looks almost like little micro grease bubbles vs air. Again, I'm about 90% +\-, going to see what comes up this weekend and it they improve... I'm not poking that bear, yet.

Quote:

Originally Posted by 80stech (Post 1224994)

Thanks 80stech! - I think that's a solid idea!

I ran my Motive at 20 pounds and actually started the process (in shop 1) with "the buddy" system, open, push, hold, close, lift and repeat. I'm thinking this weekend I will probably do a quick ABS bleed and then finish up with the buddy system to see if I can get that pedal back to 100% and call this job complete. I'm hoping that driving it this week will walk the air down the lines and make this weekend the "cherry on top" job.

Some ABS gravel road panic stops before bleeding again might help as well.
I can't believe I need to say it, but DO NOT re-use the brake fluid.

Quote:

Originally Posted by Purplefade (Post 1225003)

Well, the 993 has a known issue with sludge in the ABS unit. I'd be loath to recommend the alcohol flush out without a specific reason.