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Clutch Slave Failure

hadabadachada

New member
The guy who I make do my chores ran away, I’m screwed…

2004 R1100S 67,000 miles
Replaced my original clutch slave at 50 some thousand miles, after I checked fluid and it seemed major brown. Figured I’d get ahead of a failure and replace with an EME part. Price is right, but ehhhhhh.
At pretty much 2000 miles on it, riding home on the highway, engagement started feeling weird, no clutch. Managed to get home with no issues, thank goodness it was later at night.
Complained that that seems major early to fail, we swapped for a new one. But not after a little back and forth. Put the old stock magura back in. The bearing turned nice and smooth on it, in comparison to the failed, obviously. Kept the EME no name part for back up.

Well today’s the day I need it. Riding to the bar after work, noticed the engagement point change and knew immediately. Praise the lord I was able to turn around on the highway and head back home, 50 miles, without having to stop, with no clutch. Amazing. Couple close ones.
So I’m taking everything apart now, bearing and everything is just trashed looks horrible.

Now the background is done, my current issues,
The EME replacement’s bearing is not smooth. There’s some roughness in there. Pretty rough compared to the stock magura bearing I mentioned above, after 50,000+ miles. So I’m expecting this one to fail quickly too. Im going to get some grease to pack in there tomorrow, maybe someone can help with what grease would be best? Hoping that will take some of the roughness out, doubt it.
So I’m going to order up an ol’ expensive OEM magura part from BMW to have when this one goes.

Can anyone chime in with any kind of wisdom in this situation? Im just curious what the people who actually know something have to say, because I don’t know much.

I do know that I have horrible luck with EME parts. These no name slave bearings seem like trash, and I wish there was some way I could replace them.
I’ve sent back two fuel pumps to them because they were INSANELY loud, both of them. Almost going to order some 50 dollar one off eBay to see if it’s any better, quieter.
So I’m probably looking to get OEM anything I need at this point after these issues. Thankfully they are great people and they’ve taken care of me with replacements and/or refunds.
Done rant, need to try and clean out the hole the slave cylinder goes in, can’t reach in for crap and there’s a lot of debris in there. Hopefully the fluid didn’t get on the clutch. Didn’t seem to slip riding home. And looked like most of the fluid wept out the missing cm of gasket I cut incase it leaked like I read somewhere.
 
Hoses eh? From a Hoser eh?

You might not be returning the fluid back to the Naster Cylinder because you got a flapper in a hose, you see, eh?

It's a very simple single circuit hydraulic system, very similar to what you might see on a dump truck.

Pump to cylinder, return to tank(master cylinder in this case).

Just about no practical way I can think of to confirm that but new hoses be a bit less money than a clutch starting to slip.
 
Guess I could buy a new hose…
If the fluid wasn’t going back to the master, wouldn’t the clutch potentially “slip”?
I’ve never had the clutch slip or feel like there was something amiss.
I guess the thought is that there is excess pressure on the throw out bearing causing them to fail?
But isn’t the bearing spinning all the time under pressure anyway?

I have no issue with this OEM slave bearing with 60,000+ miles going out today, I’ve done over 10,000 miles on it since it’s second start.
but the EME no name going out after 2000 miles is suspect.
And the rough bearing in this new EME that I’m about to throw in bothers me.

Anyone know a way to change the bearing in the slave piston? Think it’s possible?

Thinking of blowing the slave port on the bike out with air and spraying brake cleaner in there and wipe, bad idea? Don’t wanna mess up any seals.

Maybe the same slave is on another bike for cheaper? Or there’s another option? BMW has the slave cylinder for just under 300 now, steep.
 
Most conclude the Magura cylinder from BMW is the way to go. Bad results from cheaper aftermarket items.
 
The clutch line is synthetic - not rubber - no internal flap possible.

Lube bearing with high temperature wheel bearing grease
Pack thru the center of the bearing with a pencil eraser until fresh grease comes out the perimeter
Make sure any excess grease is kept away from the piston seal.
I lube the bearing every 50k miles as a PM.
Presently have 230k miles on my 1150GS on the original clutch slave.
Yearly flushing with fresh DOT4 also part of the regime.

Original Magura / BMW part comes chronically undergreased as the picture shows.
 

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Guess I could buy a new hose…
If the fluid wasn’t going back to the master, wouldn’t the clutch potentially “slip”?
I’ve never had the clutch slip or feel like there was something amiss.
I guess the thought is that there is excess pressure on the throw out bearing causing them to fail?
But isn’t the bearing spinning all the time under pressure anyway?

I have no issue with this OEM slave bearing with 60,000+ miles going out today, I’ve done over 10,000 miles on it since it’s second start.
but the EME no name going out after 2000 miles is suspect.
And the rough bearing in this new EME that I’m about to throw in bothers me.

Anyone know a way to change the bearing in the slave piston? Think it’s possible?

Thinking of blowing the slave port on the bike out with air and spraying brake cleaner in there and wipe, bad idea? Don’t wanna mess up any seals.

Maybe the same slave is on another bike for cheaper? Or there’s another option? BMW has the slave cylinder for just under 300 now, steep.

The bearing spins all the time, lightly loaded by the internal spring of the slave cylinder.
The bearing can be removed by piercing the bottom tin cover with a pointed awl or 1/8" drill. Use a grease gun with a pin tip and pressurize the back cavity, the bearing will lift.
Unfortunately the bearing is not for public sale from INA, I tried sourcing a few years ago. I was informed this is a BMW proprietary part.
 

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While you are in there cut back the sleeve on the pressure line.
It fills with water and eventually rusts out the banjo fitting.
Hold back with a zip tie.
 

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Great info, thank you.
I noticed the hose is very very expensive new, so hopefully I’m not too rusted out at this point.
I’ll be looking around for the best deal on an OEM slave before this cheapo “24” fails.

Seems like this should be a regular service item. Or is it and I just missed that section?
By your routine it seems could last forever! That’s a lot of miles!

Wish I had more time to do more riding.
 
I also notice in your photo the orientation of the hoses coming from the slave. That’s how it looked when I removed it the first time, but the BMW diagram shows them opposite, so I put them on like the diagram.
Does this really matter?
C26AB791-A763-4EF9-9D43-B7DA813CC519.png
 
I also notice in your photo the orientation of the hoses coming from the slave. That’s how it looked when I removed it the first time, but the BMW diagram shows them opposite, so I put them on like the diagram.
Does this really matter?
View attachment 87998

I have always replaced as per original.
The factory CD shows the pressure line to the back as well
The fiche is a part breakdown/id and is not an assembly manual

If yours was functioning correctly I would assume it would not make a difference, however you seem to have issues with fluid return.
It is possible that the piston seal could be partially blocking the forward port.
As the clutch wears the piston moves backwards and fluid in the reservoir rises . Your machine is higher mileage.

Change them back and see if your problem resolves.
 
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I believe the photo is correct and the part fiche illustration is incorrect. I replace my clutch slave cylinder several years ago and have the hydraulic lines oriented as the photo shows and have not had any issues whatsoever. I think a key indicator of how it is designed to be installed is solved the anti rotation tab for each connection. If routed correctly, the anti rotation tab keeps the banjo fitting from rotating further while torqueing the banjo screw. If you look at the brake calipers themselves and the hand brake lever master cylinder and clutch lever master cylinder (meaning anywhere else you have a hydraulic line with a banjo fitting) there is this anti rotation tab to aid in the installation. My 2 cents for what its worth, change is optional.
 
i bought my fuel pump and magura oem clutch slave cylinder from tills.de for $100. You wont find it in stock always though.
 
i bought my fuel pump and magura oem clutch slave cylinder from tills.de for $100. You wont find it in stock always though.

Thanks!
I’ll keep that in my bookmarks list for future reference.
I got a new fuel pump from quantum, suggested on another fork
, actually is quieter than OEM, so far so good, 100 USD for pump, pressure regulator, screen, filter, the works.
Ended up getting an OEM slave cylinder and some high speed high pressure grease and packed the bearing really good.
 
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