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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: sfrligo on January 20, 2016, 04:45:32 PM

Title: Rear Brake Fluid Intake Problem
Post by: sfrligo on January 20, 2016, 04:45:32 PM

1994 K75

Realized last week my rear brake had leaked dry. Hooked up the MightyVac, put some fluid in the reservoir, and started pumping. Got lots of air, a little bit of fluid, but the level in the reservoir barely went down: fluid wasn't getting pulled into the line. I tried bleeding at caliper and ABS both, and tried combinations of pumping the foot pedal while toggling the bleeder open/closed.

Has anyone had similar issues? Any advice on how to find the leak/check whether it's the master cylinder plunger/get more fluid into the system?

Thanks!
Seth

Title: Re: Rear Brake Fluid Intake Problem
Post by: Inge K. on January 20, 2016, 05:29:30 PM

Sounds to me that the smallest port from the reservoir is blocked, or the pedal is wrong adjusted (it should
be a few mm play between the pedal and piston).

http://www.motobrick.com/index.php/topic,7738.msg54905.html#msg54905 (http://www.motobrick.com/index.php/topic,7738.msg54905.html#msg54905)

Title: Re: Rear Brake Fluid Intake Problem
Post by: sfrligo on January 20, 2016, 05:38:33 PM

Thanks for the suggestion. I haven't changed the pedal adjustment since it was working fine and was professionally adjusted. I'm pumping with the reservoir open, so it shouldn't be an issue with a hole being blocked, correct? The rear reservoir on mine is cylindrical, and just has one big hole going out the bottom. The pedal bottoms out, and pushes material through, but doesn't seem to suck any in...

-Seth

Title: Re: Rear Brake Fluid Intake Problem
Post by: Inge K. on January 20, 2016, 05:44:31 PM

Maybe this link would make it easier:

http://www.k100-forum.com/t1301-brake-seizure#47349 (http://www.k100-forum.com/t1301-brake-seizure#47349)

Title: Re: Rear Brake Fluid Intake Problem
Post by: K1300S on January 20, 2016, 06:44:06 PM

brake fluid doesn't evaporate.  if system was dry, it leaked out somewhere....find the leak.   there should be a wet spot somewhere.

Title: Re: Rear Brake Fluid Intake Problem
Post by: Brad-Man on January 20, 2016, 08:47:04 PM

Roll the bike in flour...