Removing ABS module

[winkeldc]

My abs failure kicked in last summer, and I figure now is as good as time as any to get to fixing the problem. I have an '08. It was that no/low power failure when I hooked up the code reader. (I can't remember exactly at this point and of course can't find the print out, but I remember it being the one that Module Masters cures). The shop manual mentions that the brake fluid should be drained before removal of the module. I was wondering if that's really necessary. I have seem some posts on other forums that Module Masters prefills the abs module after repairing it, and one mentioned that the lines shouldn't have been drained to save a headache upon installation. It seems easier to cap the lines and leave all the brake fluid in the lines when I remove the module, so I can just do a simple fluid replacement when I install the repaired module instead of bleeding the entire system. I think I understand that I should also run that bleed test from the GS911 on the module after the fluid replacement, and the re-bleed the calipers to finalize everything. I just can't see the need to drain the lines first, but I'd hate to second guest BMW on this one.

If anyone has gone through this, any advice is most welcome. I just want to make it as simple as possible because I really hate bleeding brakes.

Thanks all!

[deilenberger]

As long as you can seal off the lines so there is no leakage - I don't see a problem. Brake fluid is one of the worlds most effective paint removers.

One trick someone mentioned on another forum - slightly depress the brake lever before disconnecting the modulator.

You probably want to relieve pressure at a caliper bleed before cracking the line on the modulator. Slightly depressing the master cylinder closes off the hole from the reservoir to the actual cylinder - so the brake fluid won't leak out since it can't get any air to replace it in the system. Same thing on the rear pedal. I imagine some tie-wraps could accomplish this.. (haven't done it so I don't have any photos or suggestions of where..)

[winkeldc]

Thanks! I read that too, but I just don't know enough to skip steps. Draining the fluid just didn't make complete sense to me. I have some vacuum caps to cap the lines I'm hoping will keep drips away. If I can get the brake pedal tied down I'll give that a go.

[peels]

i just yanked it all off last spring. LOL made a mess. oh well

edit: oops, this is r1200r. different thing... sorry.

[winkeldc]

Just as a follow up in case it helps anyone else out, I did not drain all the brake fluid from the system before removing the abs module. I zip tied the brake levers after cracking the bleeder valves to release the pressure. The front brake was straight forward, and the rear pedal I just zip tied to the center stand. When I removed the abs module, I took some vaccum valve covers and sealed the brake lines. It seemed to work as I had very little air in the system upon reinstalling the abs module and bleeding was mostly to exchange fluid. The abs module bleed test from the gs911 introduced a small amount of air, but nothing that wasn't quickly bled.