Front brake bleeding advise needed, please!

[BMblB]

My front brake lever started going right to the grip. I could pump it up with a few quick squeezes. That didn't fill me with conficence to say the least.

Got a master cylinder rebuild kit from the BMW dealer. My mechanic (motorcycle mechanic, but not a BMW specialist) installed the kit. After bleeding the lever pumped up, but then the master cylinder to junction hose spouted a leak. Crap! Got that hose replaced.

After bleeding from via the calipers the lever went right to the grip. Crap!
After bleeding from the ABS unit under the tank it is better, but not great.

Any advice on getting the front brakes bled so they are good and hard? We are at wit's end.

[Dog Tyred]

There is a fantastic manual on how to bleed/replace the brake fluid on an R1100S with ABS EVO system on UK GS'er

I followed it and worked a treat.

Follow the link below and download the manual.

DT

Edit: Link doesn't seem to work. Drop me a PM with an email address and I'll send you a copy. Alternatively just gooogle R1100S ABS brake fluid change look for the UKGS'er link

[BMblB]

The bike in question is a 2001 R1100S with ABS. ABS only, not the fancy linked brakes.

[bfisher]

Issue resolved.

Root cause: faulty new bleed valve - there goes 5-6 hrs of my life i will never get back... Brake rebuilds.. i'll endeavor to avoid in future ; ) however you live & you learn..

[BMblB]

Issue resolved.

Root cause: faulty new bleed valve - there goes 5-6 hrs of my life i will never get back... Brake rebuilds.. i'll endeavor to avoid in future ; ) however you live & you learn..

Ummm…

So far my issue isn't resolved. Maybe you hit the wrong thread?

I'm hoping it is good enough to ride tomorrow. Fingers crossed!

[bfisher]

Oops.. your right... my 'caliper' issue are located @ http://boxertrix.com/phpBB2/viewtopic.php?t=20951

Good luck with yours...

B

[nab 301]

Any advice on getting the front brakes bled so they are good and hard? We are at wit's end.

I have a '99 11S which had abs originally. When it was operational I found I always needed a vacuum tool to do the job . I followed the manual to the letter . Bleed the pressure modulator (under the tank) first, Vr = front brake bleed screw, HR is rear ( before bleeding the calipers).

[BMblB]

My inclination is to try pushing the pistons back into the calipers (and holding them there with clamps), then reverse bleeding - pushing fluid from the calipers up to the master cylinder.

Any thoughts on that?

Also, the mechanic got the master cylinder twisted about 15 degrees toward horizontal compared to the clutch lever. Is that easy to rectify?

[BMblB]

To get the brakes back to normal I bled from the bottom up. I got a very large syringe (at a DIY store), attached tubing from that to the caliper. Attached a tube to the ABS unit, and pumped brake fluid from the caliper up and out the ABS unit.

Once I bled the calipers and lines through the ABS unit I closed up the ABS unit and pushed fluid up from the caliper into the master cylinder until I had filled (and emptied) the master cylinder a few times.

Getting the cylinder/lever/controls tilted back to normal required removing all the switch gear and loosening a single bolt. Twist to desired position and clamp down the bolt.

Does anyone know what this screw does?
Untitled by Brian Freitag, on Flickr
It seems to be secured with red Locktite.[/img]

[GerryB]

I've not stripped it , but my Suzuki has a similar screw that actually presses directly onto the brake plunger .

Looks to be the same, although its adjustable on Suzuki , not lock tite in .

[tanneman]

Resurrection.

That is the plunger acting on the master cylinder piston. Item 18 in the drawing. A real bugger to remove and best left alone as it is not necessary for disassembly of the lever. However adjusting it would give you control of the lever and piston travel.
http://www.realoem.com/bmw/enUS/showpar ... Id=32_0930

Something interesting I found whilst trying to get the brakes serviceable. Mine is non ABS and I have replaced the BMW brake lines with double brake line set up at the front. This makes it easier to bleed. However the bike is now 11 years old. No matter how many times I bleed the brakes the lever would come back to the bar. Bled the unions and in the end changed the crush washers as I thought that was at fault and sucks in air.

Took the caliper of, pushed the pistons back and pumped the lever. The piston moves on the pump stroke but on the release of the lever the immediate retraction of the piston by larger than normal amount had me looking somewhere else.

Over time the cup washer on the master cylinder piston hardens, item 13 in above drawing. It still pumps fluid but on the return it should allow for some fluid to leak past as it deforms a bit to fill the space in front. The caliper piston returns slowly and by small amount due to the restriction of the return choke to the reservoir. If the cup washer is hard then no fluid goes past it on the return hence the lever comes back to the bar as a large part of the travel is taken up getting the pistons to the brake disk.

Hope this helps with future problems. Big thanks to Peter at Scorpio Racing for pointing me the correct way.

[dysondiver]

tannerman , thats a good solve , well done .

[lesterzzzzzzzz]

http://advwisdom.hogranch.com/Wisdom/service_abs3.pdf. Not long did mine