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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: k11pfc on May 20, 2011, 02:43:57 PM

Title: Master cylinder rebuild
Post by: k11pfc on May 20, 2011, 02:43:57 PM
Tomorrow I do my MCR I am not massively confident I know what I'm doing but gonna try so wish me luck and any last minute tips would be welcome.
Title: Re: Master cylinder rebuild
Post by: frankenduck on May 20, 2011, 03:08:18 PM
I hope you read this:

My front/rear master is leaking, should I rebuild/replace it? (http://www.motobrick.com/index.php?topic=343.0)
Title: Re: Master cylinder rebuild
Post by: k11pfc on May 20, 2011, 05:11:56 PM
"Regardless, the first thing you want to do is pull the master cylinder apart and assess it's current condition before deciding upon a course of action or spending money"

Well I've already bought a rebuild kit on advice from another forum so I may as well replace it after stripping and cleaning etc. I'll let you know tomorrow if this was sucessful.
Title: Re: Master cylinder rebuild
Post by: frankenduck on May 20, 2011, 05:16:14 PM
What year and model?  (It helps others help you if you put that info in your signature. (http://ehub23.webhostinghub.com/~motobr5/smf/index.php?action=profile;u=2;sa=forumProfile))

Front or rear?
Title: Re: Master cylinder rebuild
Post by: k11pfc on May 21, 2011, 07:48:25 AM
Sorry it was a front cylinder rebuild on a 1997 K1100rs, and to my great delight I have completed it in 2 hours, the most difficult part, (for me) was finding retaining screws. Otherwise a doddle. Just going out for a fast hard run to check it out. If I don't post again you will know I buggered it up!!!  ;D
Title: Re: Master cylinder rebuild
Post by: mystic red on May 21, 2011, 10:57:27 AM
When I bought my K11LT I had a sticky front caliper. Bike came with all maintenance records and I went through it. No mention of brake fluid change.
I did the bleed and what came out was atrocious. Caliper still sticky. Against strong advice from across the pond I bought a caliper rebuild kit and did the work.  I was told by this person across the pond that invariably, if you split the caliper, it would leak. Not so.....
Anyway, I figured that the master cylinders were going next and I had the source handy for the kits so I pulled the trigger on the front and rear. They still sit in a parts drawer, untouched....maybe someday.
Title: Re: Master cylinder rebuild
Post by: k11pfc on May 21, 2011, 03:00:39 PM
No leaks whoopee do.. ;D
Title: Re: Master cylinder rebuild
Post by: mystic red on May 21, 2011, 03:13:49 PM
Gotta love that...
Title: Re: Master cylinder rebuild
Post by: Lawrence on September 20, 2011, 11:17:53 PM
On the K100RS of 1985 vintage, the front brake m/c reservoir is retained by three long bolts.  I noticed some weeping for brake fluid at the base.  I'd experienced this on airhead m/c too.  There is an o-ring seal at the reservoir base that grows tired.  Anyway, with the bolts that hold the cap on removed, on the airhead m/c you can simply pull the reservoir off the actual master cylinder.  Not so on the K100RS. I check the parts schematic and can't for the life of me see what's holding it in place.  Anyone?
Title: Re: Master cylinder rebuild
Post by: Inge K. on September 21, 2011, 04:23:49 AM
Pull straight up, could be some corrosion that make it stubborn.

Inge K.
Title: Re: Master cylinder rebuild
Post by: blakey on September 21, 2011, 08:11:15 AM
No it won't pull straight up...there's a small Phillips head screw that comes up from underneath that holds the reservoir on.
Title: Re: Master cylinder rebuild
Post by: Inge K. on September 21, 2011, 05:49:02 PM
Sorry for the wrong answer, did not remember that last screw
(have to blame the age or the beer or both).

Inge K.
Title: Re: Master cylinder rebuild
Post by: Lawrence on September 21, 2011, 06:54:22 PM
Thanks for saving me from myself, Blakley.  I went back and had another look at the exploded view of the m/c and found the screw in question.  I don't know how I overlooked it the first time.  Wait!  I know... old age  ::) ::)