WRT to your rebuilding question, it's possible to rebuild anything if you're willing to search for parts, BUT a quick check of the BMW parts diagram shows that BMW will only supply the clutch slave as a unit, so you'd be on your own looking for rebuild components.
When I did mine years ago, I thought I'd just be doing a rebuild, but ended up replacing the whole unit because BMW doesn't provide parts for rebuilding.

21522333433 OUTPUT CYLINDER CLUTCH - D=20 0.32 1 $134.25

http://www.maxbmwmotorcycles.com/fiche/DiagramsMain.aspx?vid=51717&rnd=03192010

I am just wondering if it's possible to upgrade the bearing and seal ?

I took it apart and I can't get the bearing out of the piston , any ideas ?

Can the clutch system be changed over to silicone fluid ?

Isn't silicone compatible with bearing grease,trans fluid,and motor oil ? i.e. no seal issues.

Note that I did not use any tools to remove the push rod and there is what looks like
plier marks on the rod. Maybe the dealer did this from the prior slave install ?


What do ya guys think ?

Thanks Tom

 

You can also get a new slave cylinder from beemer boneyard, for about $80 as I recall.

 

Thanks for the photo Tom, now I won't have to take mine apart to see what is inside. A usual habit of mine and I guess yours too I understand your question about converting the system to another fluid and I cannot answer that question. However, that is a good question for someone who is an expert in hydraulic control systems.

I can tell you that I just ordered a new aftermarket slave cyl. from Beemer Boneyard for $85. For that price, I can't justify trying to rebuild my old one, which is not leaking, by the way, I just have it out to do the weep hole procedure and @ 65k miles the replacement is a preventive measure.

 

Tom, is the end of the pushrod bent or is it an optical "delusion"? I'm referring to the turned down end, to the left in your picture.

If it's bent better get a new one of those on the way too.

Loren

 

Several years ago I sent a couple failed slave cylinders to a friend who designs hydraulic mining equipment. He found that as the rubber plunger wears it sheds very small balls of material that eventually gather at the sealing surface and create a space for the fluid to leak. His supplier of such items recommended a slightly different material and I bought a bag of them. I have now rebuilt and reinstalled five of them and have not encountered a failure. BTW only one went on my bike the others went in bikes while they visited Jeff's Strip Joint. The part is actually a metric U cup N14 x 20 x 4 and the original is nitrile rubber. The replacement parts I was sent were actually Buna material, whateverthehell that is. I think I eneded up paying $4.39 plus shipping for 25 of them. Still have a drawer full of 'em in the garage.

 

Several years ago I sent a couple failed slave cylinders to a friend who designs hydraulic mining equipment. He found that as the rubber plunger wears it sheds very small balls of material that eventually gather at the sealing surface and create a space for the fluid to leak. His supplier of such items recommended a slightly different material and I bought a bag of them. I have now rebuilt and reinstalled five of them and have not encountered a failure. BTW only one went on my bike the others went in bikes while they visited Jeff's Strip Joint. The part is actually a metric U cup N14 x 20 x 4 and the original is nitrile rubber. The replacement parts I was sent were actually Buna material, whateverthehell that is. I think I eneded up paying $4.39 plus shipping for 25 of them. Still have a drawer full of 'em in the garage.

Thats it. I was trying to get one in viton, which stands up to temp better. How much for you to send me one? Buna and viton are just types of rubber compounds. It probably the same since buna, I believe IS Buna Nitrile.

Zeke

 

To wa1200lt : That is an optical illusion in the pic but I'm still gonna replace the rod because the scratches are worse they look in the pic.

To jeffklt : Thanks for the info. How did you get the bearing out ?

To Charlievt : thanks for that excellent website .

I plan to order a new cylinder from Beemer boneyard and install it with a new rod,seals, clutch,and more seals.
But if perhaps someone knew that upgrading the seal,bearing and or fluid might work then we all could justify it because clutches aren't cheap and even though I enjoy tearing the bike apart to achieve that sense of satisfaction when it's all done I'd rather spend the time and money on some new farkles or gas and miles.

 

Thats it. I was trying to get one in viton, which stands up to temp better. How much for you to send me one? Buna and viton are just types of rubber compounds. It probably the same since buna, I believe IS Buna Nitrile.

Zeke

There is no temp problem at the slave cylinder. It never gets hot enough to be a problem with the standard seals. The temperature range of Viton is of no help here, but wear and fluid resistance may be.

 

I would not try to use Silicone brake fluid here. Silicon fluid was designed for racing brake systems, where high temperature is a problem. It should NEVER be used to replace normal DOT 4 fluid, because absolutely every trace of DOT 4 has to be removed from the system first. Also, Silicone fluid can cause worse corrosion problems because moisture will not be absorbed into the fluid like in DOT 4, where it is so distributed into the system that it takes a considerable moisture buildup before corrosion is a problem. With Silicone, moisture will gather at the lowest points in the system, such as the bottom of cylinders, where it starts rust in a small area.

Unless a system is designed for Silicone fluid, and factory filled with it, trying to switch over from system originally filled with DOT 4 helps nothing, and causes problems that did not exist previously.

 

Thanks for saving me from screwing up my clutch system dshealey
What you say makes perfect sense because someone I know converted his car brake system over to silicone and just recently mentioned having to replace some brake lines due to rust.

So does that leave viton or buna or buna nitrile seals as an option ?

Tom

 

Ok I did a little research and found some sites that may be of interest to some

http://www.motorcycleproject.com/motorcycle/text/cows-brakefluid.html

http://www.advancedgasket.com/pages/orings/oringdata.htm

I am now convinced to just buy and change out the slave cylinder ,motor and trans seals, drill the weep holes to try and prevent another clutch contamination.

no sense in trying to reenvent the wheel when you veterans have already done my homework and showed me the cheat sheet so i'll become an conformist

Once again Thanks to all of you guys for this forum which makes owning a k1200lt less taxing from the stealers.

 

You also need to remember that the slave cylinder was upgraded sometime during 2001 (?), with the same part number. What the upgrade consists of I do not know. So depending on what slave cylinder you have, I would just go with a new one.