Rear brake

[Billk]

The rear master cylinder on my 1995 K75 was leaking. I removed it and honed it out with 0000 steel wool. No leak now. I am now unable to pressure / bLeed the system. I think I might have gotten some air into the ABS. I've used a harbour freight bleeder, I have tried to reverse bleed with no avail. When I tried reverse bleeding I did here a click from the ABS. Does anybody have any ideas? I was thinking of just getting rid of the ABS in the rear cause I'm sure it would be easier to bleed without it. If I got  rid of the ABC is it just a matter of buying a rear hydraulic brake line, like the bikes that have no ABS and by passing the ABS?

[Billk]

The saga continues. I took the master cylinder dust cover, the half circle rubber boot and noticed that the piston seemed stuck all the way back in the master cylinder's bore. There was a large space between the pedal and the piston bore. I have to remove the piston to see why she's stuck in the bore. The saga continues.

[ttown95LT]

Had the same issue back in April with mine, if you'll read the Clymer manual you will find it is virtually impossible to bleed the rear brakes with the hand operated vacuum brake bleeders.  I purchased a Power Bleeder from Motive Products, it even comes with the correct cap to fit the BMW reservoir. Had the job finished in less than 5 minutes.  You will be amazed at how quick this makes bleeding the brakes.

[Scott_]

If you have a friend in the HVAC service field ask if you can borrow his industrial grade vacuum pump.
I've go one that I use for brake bleeding on my bikes. Works like a charm.

If you watch for any medial equipment surplus auctions you may be able to pickup a used medial suction machine cheap, one of those would work good too. If you are lucky it may even come with the collection jar and tubing........

[Billk]

Installed a new rear master cylinder on my 1995 K75. I now have a functioning pedal but on the soft side, even though I used the Harbour Freight bleeder.
Ttown  could you give me the information on the Motive Product, Power Bleeder, where you bought it, price and does it come with the reservoir cap I need for a 1995K75.
Bill

[wmax351]

You could also use the 15 dollar venturi type vacuum pump from harbor freight. It works for HVAC stuff if you have a big compressor (I used it on my car) but even with a littler compressor, it will pull a 29 inch vacuum for a little while.

[johnny]

no soft pedals on my motobricks...

i think the trick is slow and methodically... this is what i do...

agitate brake lines in attempt to release any bubbles before and during the bleed process...

full reservoir... open abs bleed valve... slowly push pedal down... close abs bleed valve... slowly let up on pedal... repeat till fluid runs clear and all little tiny bubbles are gone...

full reservoir... open caliper bleed valve... slowly push pedal down... close caliper bleed valve... slowly let up on pedal... repeat till fluid runs clear and all little tiny bubbles are gone...

j o

[Grim]

95 would have ABS II would it not? I didnt see where you confirmed you got it out and bypassed.

If its still inline did you bleed the ABS modulator under the seat? Till you bleed that you will not get a good peddle.


I have had no problem pump bleeding on mine (pump peddle hold and open the bleed valve).

If air ir strapped in the caliper sometimes tapping it with a wrench will help. Same deal with the master. 

Another thing that might help is while using a vacuum on the bleed valve open it and push the pistons in. That will help get any sour fluid out. The bleed valve and inlet are on top so when you bleed you are not clearing the dirty fluid out and if the pads are worn that would increase that volume. Pushing them in with the bleed valve open will push most of the old fluid it out.
Make sure you pump it back up and get the pistons extended and top off the reservoir before going for your test ride.