re-sleeving the master cylinder

[Milo_357]

Has anyone here ever re-sleeved a master cylinder in the right handle unit?

What was involved?  I was thinking of going to a machine shop.

[Matt Chapter]

Last time I had trouble with my master cylinder, I just replaced it.  Ordered it from motobins, it's about 140 USD plus shipping.  Plug and play, once you get it bled life is good again.

[wa1udg]

How bad is it?  You can polish out a little corrosion with a dremel mounted conical wire brush.  You don't need or want a mirror finish, it's like cylinder bores which are ittentionally cross hatched.

[montmil]

Larry Stonestreet, aka: Stoner, recently wrote on the Airhead List:

"I talked to Cycleworks a year or so ago when I was replacing a lot of MCs, and Dan thought he could sleeve these things for around $70. Once I bought a new $66 piston kit from BMW it wasn't cost effective because new handlebar-mounted MCs retail for under $200. I never pursued it, but if you want to just give him a call."

Personally, I've seen complete MC prices run to $400. Do not know if the $200 price is current or not.

Monte

[Justin B.]

I have thought about it.  If somebody could come up with just the rubber bits for cheap it would make it worth pursuing.  It's a simple casting so I would think one could make up a brass sleeve and press it in fairly easy.

[Milo_357]

It's frustrating to know what to do..  I just do NOT have ~ $400 bucks right now...

I've read a few things that implied re-sleeving and using the old piston will solve the leakage problem, other the exact opposite.

Here appears to be the replacement piston.

http://www.beemerboneyard.com/32722302356.html

Justin, I may be wrong, but I think this has all the rubber bits in place you where talking about.  And the price is pretty goo.

Monte, got that email from Larry.  I already have a message in with Cycleworks and hope to have a response soon.


So what do ya'll think?  New piston or resleeve?

[Semper Gumby]

Hmm.  My 16mm is a little strong for the dual Brembos.  Could I sleeve it and make it a 15mm?

There is a chart somewheres that says this would be a good thing...

[Barry]

There is a chart somewheres that says this would be a good thing...  

Here it is

http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1290616014/3#3

[Justin B.]

You could theoretically make the sleeve any size you as long as you had a piston and rubber bits.  $36 is not bad for the piston assembly but it would be nice to be able to just get the rubber for $5 - $10 and then machine a SS piston, re-sleeve the cylinder with brass and you would basically have something that would never wear out except for the occasional rubber re-new!

[Milo_357]

You could theoretically make the sleeve any size you as long as you had a piston and rubber bits.  $36 is not bad for the piston assembly but it would be nice to be able to just get the rubber for $5 - $10 and then machine a SS piston, re-sleeve the cylinder with brass and you would basically have something that would never wear out except for the occasional rubber re-new!

Justin, is there a trick to getting the piston back in the sleeve?  When I took my MC apart to clean it, the larger, upper seal tore apart.  It was the seal that was reverse shape of the cylinder.  

Was was told that the piston was SUPPOSED to come out easily. Ha!  Any thoughts?

Thanks,

Dell

[montmil]

Anybody else beside me that subscribes to Motorcycle Classics magazine? The American-published vintage bike mag outta Kansas?

The latest Sep-Oct 2011 issue has a four-page, step-by-step, color photo article on rebuilding the Brembo F08 brake caliper.

That's the one on the front of our favorite Airhead and used by just about every European bike manufacturer in the mid-70s up to the early 1990s. Discounting the few ATEs on some early model R65s.

This article is going into my tech manual binder.