Clutch Slave Cylinder

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Photoguy
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Clutch Slave Cylinder

Post by Photoguy »

I've been reading up on the slave cylinder for the clutch and have learned that without proper maintenance it could lead to a work of problems. Just the other day I discovered where it was and truthfully had given no thought to this at all, but it makes sense to me that after 17 years and 30k miles it should probably be looked at. Just digging into the research now and have a quick ? for anyone that's been there done that...This is probably the first of many ?'s

-Is it a given that the SC needs replacing? Or...is there some kind of maintenance to do to it? ...ofr more likely does it 'just depends' on what I find?

- I presume that the SC can be removed once the rear wheel and rear shock is out of the way, but is the internals of the unit sealed...or will brake fluid escape once the cylinder is removed? I think I saw that there was a gasket there and just trying to understand what I'll find inside.

-To do a bleed I presume that the <insert proper name here> plug that is on the extension hose secured to the right rear bike frame should be replaced with a speed bleeder?

And, as always, thanks for any insight-
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EasyBee
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Re: Clutch Slave Cylinder

Post by EasyBee »

Replacing the clutch fluid is described on page 59 of the maintenance manual
https://www.dropbox.com/s/8cb55xst44iw3 ... S.pdf?dl=0

Can't help you with removal.

Found this from Sykospain.
Taking half the bike apart https://www.youtube.com/watch?v=HmaW3QekTG0 although he writes in the comment "Here's how to access it WITHOUT ripping the bike in half."

Found this, but it's a R1200 GSA https://www.youtube.com/watch?v=HmaW3QekTG0

Mind you : Totally different fluid, R1150 manual says DOT 4.
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Photoguy
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Re: Clutch Slave Cylinder

Post by Photoguy »

Thx Mr. Bee. This gives me something to dig into a little further. Hoping to avoid a situation and be ready for what I might encounter. This is a little premature as I'm trying to be proactive and get things in order before proceeding. Have you gotten into this item on your bike?
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Re: Clutch Slave Cylinder

Post by two wheel tango »

I’ve reflected on proactive maintenance on this but decided to dig into it if/when there’s a hint of a problem... either dark/contamination of clutch fluid or noticing a related drivability problem. I think those would be early warning signals.

FWIW- 130K miles and has not been a problem. Not sure if it’s a given that they all will fail at some point or whether some are just prone to failure because they were not greased right from the factory. Also curious to learn more...
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Photoguy
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Re: Clutch Slave Cylinder

Post by Photoguy »

two wheel tango wrote:I’ve reflected on proactive maintenance on this but decided to dig into it if/when there’s a hint of a problem... either dark/contamination of clutch fluid or noticing a related drivability problem. I think those would be early warning signals.

FWIW- 130K miles and has not been a problem. Not sure if it’s a given that they all will fail at some point or whether some are just prone to failure because they were not greased right from the factory. Also curious to learn more...
I'm just parroting what I've read elsewhere but it did make sense to me which is why I've started to think about this. Essentially though my interpretation of what I've been reading is a combination of factors: delicate design, light on the lubrication and that the DOT 4 fluid that is used retains water which makes it's way down into the slave cylinder and without any visible signs outside of the unit can do some bad stuff to the bearings and seals in the SC and ultimately affect the clutch at significant cost to repair....as in thousands.


And for the record, I'm really confused if this is one of those things that get written about with a sense of alarm of if it's *really* an issue. Maybe step one would be to bleed the clutch and take a look at the fluid that comes out as a sign what might be lurking inside the SC?

Also, it's a $200 part, fwiw.
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Re: Clutch Slave Cylinder

Post by Sunbeemer »

Maybe step one would be to bleed the clutch and take a look at the fluid that comes out as a sign what might be lurking inside the SC?
That's a good approach...bleeding the clutch fluid is a routine maintenance item. DOT 4 brake fluid used in it is hygroscopic and needs to be changed every once in a while same as it does in the braking systems, although it doesn't undergo the same type of heating & cooling cycles as it does in the brakes so I suspect it should be less degraded over time.
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Re: Clutch Slave Cylinder

Post by Buckster »

I change mine every year when I change the brake fluid. I think it calls for it to be done every other year.
I really don't worry about slave cylinders, splines, final drive anymore. If it happens it happens....I have had 78K miles virtually trouble free. I love this bike.
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Re: Clutch Slave Cylinder

Post by Boxer »

Photoguy, It has been a while since I had my R1150R and worked on that SC, but I DID take it off and Cyclerob and I did the preemptive hack on it to avoid the dreaded DOT4 fluid migration over to the clutch plates. The problem being, that the seal would leak and the fluid would find its way along the pushrod into the dry clutch housing and foul the clutch plates, causing clutch slippage, etc. That never happened on mine but I didn't want it to be a potential problem so Rob and I did the little hack job on it. It effectively allowed the fluid to drain out on the ground instead of working its way over to the clutch, in the case of a leak. I have a pic here somewhere...This is the back side of it with the little thin gasket. The whole unit will detach with the fluid hoses attached, but to do this hack, we took off all the hoses and just refilled/bled the cylinder after reinstall.

Image

To answer your question, the SC acts like a brake master cylinder and has a bleed nipple on it to bleed it if needed (I may be in error on that bleed nipple). Inside the hydraulic cavity where the fluid rests is a plate that pushes the rod, which in turn pushes the clutch plates.When you detach it, it slides off from the pushrod and will NOT dump fluid all over, if I recall properly. It is kind of hard to access since a frame connector is positioned right in the way...but it CAN be done. Because I did it and I didn't have to remove that frame bar under there. Hope this helps.
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Re: Clutch Slave Cylinder

Post by Bogdan »

I assumed everyone changed the clutch fluid when you did the brake bleed. In my mind it wan't an option. Mine looked clean the two times I did the deed; the fluid was in there around two years..Last time I changed to the speed bleeder. The YouTube video guy did it with every thing apart and the line removed. I, for obvious reasons, wanted to do it with the line still attached and so I did. You need some torque to remove the o OE bleed piece. I accessed a portable vice to hold the line in place. Like a lot of jobs, way easier with two people. Didn't lose much fluid. I like speed bleeders. In this case the change makes even more sense as you don't need the special unit to bleed.
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Re: Clutch Slave Cylinder

Post by Photoguy »

Thx for the input guys...very helpful.

I think I'll start with a bleed and see what the fluid looks like before digging further into it. It's one of those things that in some circles this is discussed as a time bomb waiting to go off and take the clutch with it, and in some ways that makes sense to me. The SC's are old, the fluid collects water and in time will probably fail. But, what's the likelihood? I'd bet that while there may be some bikes with issues there are probably many that are in fine shape with lots of miles under them. So, I'll bleed and see if that tells me anything. first order of business is to figure out how to get the plug out and replaced with a speed bleeder. Interesting to me that BMW would use that system since this *is* the bleed point, right?

And, I'm slightly hesitant to casually replace the SC for a few reasons- 1.- finding the time and 2.-without a bike lift this is a lay on the garage floor after taking a bunch of things off the bike to gain access to the slave cylinder. And the slave cylinder is a $200 part that I'd rather not spend if it isn't really necessary.

Also wondering, I've read that 5.1fluid may be a good substitute for 4 as it's less hydroscopic? Which as Boxer mentioned, is the issue. Fluid (water) that collects in the brake fluid makes it's way to places it shouldn't be.
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Re: Clutch Slave Cylinder

Post by Hoof »

Changing the clutch slave cylinder is easy compared to splitting the bike in half to replace the clutch if the SC fails. If it looks good and there is no migration of oil visible behind the starter motor it's still IMHO worth drilling the safety hole in case of failure.....I wish I'd done that!
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Re: Clutch Slave Cylinder

Post by Hyja1 »

Just wanted to add that I replaced the original factory clutch end plug with a speed bleeder and it was not difficult. It came off with two wrenches, a firm grip and turn. Much easier than I thought it would be after reading that it was going to be a tough go.... At least that was my case.
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Re: Clutch Slave Cylinder

Post by Bogdan »

Lucky you, Hyja1. In my case there was some German version of red Loctite holding it together....needed the help of a portable vise.
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Re: Clutch Slave Cylinder

Post by Tundra Dweller »

Hoof wrote:Changing the clutch slave cylinder is easy compared to splitting the bike in half to replace the clutch if the SC fails. If it looks good and there is no migration of oil visible behind the starter motor it's still IMHO worth drilling the safety hole in case of failure.....I wish I'd done that!
Please post where said hole should be drilled and approximate diameter.
Thank you!
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Re: Clutch Slave Cylinder

Post by Photoguy »

I'm curious too. I remember seeing a video but it's been a while. I'll try to find it and post it up if I can.
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Re: Clutch Slave Cylinder

Post by sweatmark »

Tundra Dweller wrote:
Please post where said hole should be drilled and approximate diameter.
Thank you!
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Re: Clutch Slave Cylinder

Post by Mrclubike »

Tundra Dweller wrote: Please post where said hole should be drilled and approximate diameter.
Thank you!
This is definitely on the to do list :smt003
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Re: Clutch Slave Cylinder

Post by Photoguy »

Thx for posting that photo. That would make perfect sense to me except I guess I don't understand how the whole thing works.

So, just trying to understand- presumably the 'piston' slides inside of this housing, it 'lives' in the piece that was removed to expose this housing. I'm wondering how does water migrate from the piston end to here? Bad seals? And if water migrates doesn't hydraulic fluid?

Thx-
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