Quote:
Originally Posted by ard
I once emptied the braking system on an E39 during a 150 mile drive with a ruptured brake line... (younger and dumber)
As a result, when I repaired the hose and refilled- the bleeding would just not work. Tried it for hours, adding fluid, helper pumping brakes.
Gave up, had a master tech at the dealership do it. (Apparently you need to actuate the ABS system to drive fluid/air in/out of that.) Edit- This was before I had BMW tools on my laptop
He said it took 3 tries to nail it.
FWIW
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Thank you Ard for the contribution. Makes me feel 100% better about my situ. Was actually just going to post an update. I did empty a lot of the system before the ABS pump when swapping the booster, despite my best attempts at keeping fluid inside the master and capping the loose lines.
So the update. I took the X for a drive around the neighborhood just now. Brakes feel very good. Maybe 95% of "normal." No more lack of assist at all that I was experiencing last night. So letting it sit overnight after all the bleeding and then moving it back and forth actuating the brakes over and over must have gotten some air to exit at the master overnight. So I guess I'll throw another quart of fluid through it and that should "get 'er done." So relieved, was haunting my dreams last night, literally.
BTW, my bleed procedure:
- Hook up to ISTA-D with ICOM (complete identification required)
- Fill pressure bleeder with brake fluid and attach to master cylinder
- Pressurize bleeder bottle
- Navigate in ISTA > Service functions ‐ Chassis/Suspension ‐ Traction control systems ‐ Bleeding routine
- Add bleed routine to test plan and run it
- Open bleeder at right rear of truck
- Actuate the ABS pump using the bleed routine
- Close bleeder and pump pedal 5-10 times
- Tap on caliper with rubber mallet and open bleeder for a few seconds (stream is solid at this point) to try and free micro bubbles
- Close bleeder, clean area
- Repeat steps 6-10 for left rear, right front, and then left front
So, hopefully this is going to have a happy ending without any further monetary expense (beside another brake fluid bottle) or damage to my ego. I was starting to second guess my re-installation of the master on the booster as it doesn't seem to fit exactly flush on the bottom and pushes out a tiny bit when actuating the pedal. Thought I might have gotten the booster's push rod misaligned with the master cylinder piston when reinstalling, but if that happened I'd imagine it wouldn't brake as well as it now does. I was getting paranoid.