RE: R1100GS Master Cylinder

[RoboBoxer <roboboxr@xxxxxxxxxxxxx>]

Thanks Tom,

The rebuild kit is available according to the on-line parts fiche at Max
BMW. I use only Castrol LMA. What you say makes sense about the crystallized
brake fluid. I think that is what I am seeing. Looks like my best bet is to
replace the piston/seal assembly and put on a new rubber boot.

Regards,
Paul T. Donoghue
Highlands Technologies, Inc.
 

|-----Original Message-----
|From: owner-oilheads@xxxxxxxxx 
|[mailto:owner-oilheads@xxxxxxxxx] On Behalf Of Tpcutter@xxxxxxx
|Sent: Saturday, January 08, 2005 7:48 PM
|To: oilheads@xxxxxxxxx
|Subject: Re: R1100GS Master Cylinder
|
|In a message dated 1/8/05 5:34:33 PM Eastern  Standard Time, 
|roboboxr@xxxxxxxxxxxxx writes:
|<<I have been having  reoccurring problems with the front 
|brake lever hanging up. Upon disassembly  of the front brake 
|lever, and removing the rubber boot on the master  cylinder, 
|some type of corrosion is found. I've removed the master 
|cylinder  piston twice and cleaned up the bore. I've cleaned 
|the piston and seals, and  re-installed using the original 
|components. The corrosion came back once. I'm  not sure if I 
|just need a new rubber boot to seal better or should go ahead  
|and replace the piston and seals as well as the rubber boot? 
|
|Anyone  experience this type of problem before?>>
|
|I  think you will have trouble getting a rebuild kit for that 
|master cylinder. I  know that some are unavailable. 
|
|What kind of brake  fluid are you using? If you are using 
|DOT5, that's your trouble. Use Castrol  GT-LMA (Low Moisture 
|Absorbing) DOT 3/4 brake fluid and change it annually. This  
|will eliminate the corrosion problem pretty well.
|
|If  the seals are leaking, the buildup you are seeing is not 
|corrosion per se, just  dried up, crystallized brake fluid. 
|The leak is a warning sign to fix the  trouble before you lose 
|brake pressure.
|
|Tom Cutter  
|

------------------------------