R1150RT Clutch Slave rebuild

I can't get the new seal fitted. It's a tough old bird and my thumbs aren't strong enough. Anyone done this successfully?

Can you make up some sort of guide from a plastic bottle. Then lubricate the said bottle and seal. slide seal up the guide and onto the piston?

Let the seal soak in brake fluid for 24hrts prior to mounting it, think of it as of a sponge, and it will get on.

Dan.

I can't get the new seal fitted. It's a tough old bird and my thumbs aren't strong enough. Anyone done this successfully?

Morning Lee

I have only done a couple so not sure I have the best answer but I just put the seal out in the sun on my asphalt driveway to heat it then used Hydraulic brake assembly lube for rebuilding brake calipers to lubricate & they went right on with finger force (but I have strong fingers).

Without having any "Hydraulic brake assembly lube for rebuilding brake calipers" handy then Dan's soaking in brake fluid might be the next best thing.

Many experts on these BMW Boxer forums feel that a Slave Cylinder rebuild kit is a waste of time and money. It's the pathetic little under-specified ball-bearing race that invariably fails, because throughout all your years of enjoying the thrill of riding a BMW 6-speed boxer motorcycle, that little pathetic ball-race is permanently spinning at crankshaft speed.

Leading to leaking DOT4 and bearing grease combining to cause contamination of the gearbox output shaft's Input Seal that lies deep in the cavity in which the slave cylinder spends its brief, benighted life.

When that cocktail of foul-smelling liquid climbs inside the cavity up to the height of the long actuation pushrod tube, the poison migrates along the rod, passing by the little, short anti-rattle felt sleeve ( it's ~n o t ~ a lube barrier ) and there goes your clutch friction plate. Thereafter, big trouble, señores y señoritas....

So it's more sensible simply to buy the better-quality non-Magura slave cylinder that's made in Italy, not Slowakia from where BMW buys the OEM part for about ten snoojits apiece. And charges 150 each to us. And which seems to be made of used Wrigleys chiclets.

And Incidentally I don't understand ( but then I'n no expert ) the reason for the larger ball-race that sits inboard of the gearbox Output Shaft's newly-specified viton Input Seal that you have to buy when doing this job. The pushrod tube doesn't rotate, it's the rod inside the tube that spins. So why is there a ball-bearing there ?

Mind you, as some wise person on this forum said not long ago, "The hydraulically-actuated clutch fitted to the 6-speed BMW bikes was the combine's answer to a question that no rider ever asked."

Never was a truer word spoken - what the feck is wrong with a CABLE-operated clutch ?

Doh - what a bozo am I. "A little knowledge is a dangerous thing". Well said, Mr. Aristotle or whoever....

OF COURSE the sodding tube rotates, that the actuation push rod slides through - it's got the spline on the other end, you knucklehead ! That's why there's a ball bearing race in the bottom of the cavity that the Clutch Slave Cylinder sits in.

I realised that when being scared sh*tless by watching this rare Chris H video on how to fit a new splined Gearbox Input Shaft. :-

Al - cap in hand with head bowed in sunny Andalucía. Give him five hours of detention.

For my money the complete replacement slave cylinder is the only way to go. Total agreement with Alan above. Remember, the tiny little bearing in the slave cylinder piston is turning at crank shaft speed at ALL TIMES when the engine is running, NOT just when the clutch lever is pulled. And WHEN that little bearing fails it takes the clutch disc out, too. That's why you drill a weep hole in the bottom of the slave cyl housing.

For just getting that seal on, I'd soak it in hot water for 30 seconds, put a few drops of P-80 on it and slide it on. Then I'd throw it away and order Alan's slave cyl.

For my money the complete replacement slave cylinder is the only way to go. Done Total agreement with Alan above. Remember, the tiny little bearing in the slave cylinder piston is turning at crank shaft speed at ALL TIMES when the engine is running, NOT just when the clutch lever is pulled. And WHEN that little bearing fails it takes the clutch disc out, too. That's why you drill a weep hole in the bottom of the slave cyl housing. Done

 

For just getting that seal on, I'd soak it in hot water for 30 seconds, put a few drops of P-80 on it and slide it on. Then I'd throw it away and order Alan's slave cyl.

Hi Guys, Im noticing lately that my clutch lever bites almost straightaway without having to let it out a lot. As the clutch is not slipping I was wondering if perhaps it will be the clutch slave instead but im not seeing any leaks.Any advice ? 2004 r1150rt 50,500 Miles  

34 minutes ago, dougiedickson said:

Hi Guys, Im noticing lately that my clutch lever bites almost straightaway without having to let it out a lot. As the clutch is not slipping I was wondering if perhaps it will be the clutch slave instead but im not seeing any leaks.Any advice ? 2004 r1150rt 50,500 Miles  

Morning dougiedickson

That is usually a sign that your clutch hydraulic system has some air in it. Try a good clutch bleeding with new fluid, if the problem goes way then you had air in the system.

If the problem then returns at a later date  suspect that you have a bad slave cylinder that is pumping air in as it works.

Thx for the quick reply bud !! I thought that too and thought if i pumped the lever a few times then I would notice a difference but it was just the same. I,ll have to get a nipple then for the pipe. Do you recommend I buy a speed bleeder nipple?

22 minutes ago, dougiedickson said:

Thx for the quick reply bud !! I thought that too and thought if i pumped the lever a few times then I would notice a difference but it was just the same. I,ll have to get a nipple then for the pipe. Do you recommend I buy a speed bleeder nipple?

 

Morning dougiedickson

You really don't need a speed bleeder for the clutch as you can easily reach the lever & the bleed screw.

You will need a bleeder screw that has the proper pointed end so it opens the check ball in the quick-fill adapter.  (BMW p/n-  34212330310)  -- you can use a standard (I believe 10mm x 1 bleed screw if the  point is correct (or you grind the point to work)

Or you can just remove the factory quick-fill adapter & throw it away  (it is ONLY needed for first factory clutch fill).

Then the bleeder nipple (or speed bleeder) can be screwed directly into the hose.

You just have to be ultra careful in removing the quick-fill adapter  as it usually takes some heat to loosen the threads & there is a very fine line between ENOUGH heat & TOO MUCH  heat. With just a little too-much heat the hose end will pull off rendering the hose useless to retain fluid.   

If bleeding with factory fill adapter still  in place then you have to adjust the added bleeder screw to open the inner check ball to get fluid to flow out.

Opinions differ about the use or not of the original SpeedBleeder nipple item from the USA. 

I'm a real fan; with two on the Rockster's front Tokico calipers, ( the small-thread nipple Part Number SB7100S is needed ) plus one on the rear Brembo caliper and one replacing the "factory chunk"  ( Werkstück )  useless-load-of-crap that's Loctite®'d on the end of the clutch slave bleeder hose, the short tube.

DR is quite right about care needed when heating the Werkstück in order to be able to undo it.  In his previous incarnation as Affordable Beemer Services in Manchester, N.H., our great mentor Chris Harris - now ensconced at his new base in the depths of a magical forest in Maine - has a very useful short video on the Toob showing what you do.

https://www.youtube.com/watch?v=cYPAmrUyiyA

And at only 9 or so snoojits apiece, direct from a friendly girl called Whitney in the sales off ice at the US factory, why on earth would you mess around with the old Squeeze-open-shut-Letgo-and-then-repeat-65-times routine ?  The main thread on the SB even comes already coated lightly with a smear of Loctite®.

So you just open the ball-valve nut on the end of the SB with your 8mm ring-spanner and then squeeze away at the lever to your heart's content, whilst watching the level in the fluid reservoir on the h/bar to make sure it doesn't drop too low.  When all the air bubbles and other gunge have rolled down your transparent tube into the waste bottle, just nip up the nipple-nut.

Kushtie....

Old topic but past experience on my r1150GS and again just this past weekend on my r1150RT:

• Slave cylinder rebuild kits are generally a waste of time and money, as the failure is usually caused by the slave piston spinning inside and wrecking the cylinder bore
• Honing the slave cylinder bore to remove  the piston spin-grooves is not only time consuming, but removes too much metal, The new seal will usually still leak afterwards as it is not spec'd for the increased bore size
• The cause of the failure is usually a partially seized slave bearing anyhow (which doesn't come with the rebuild kit) which contributes to the piston spinning and wrecking the bore
• Having tried the rebuild process a couple of times in the past with supposedly fresh and quality kits (ASE certified mechanic, with a part-time shop and about 50 years of experience), I can honestly say that refitting the piston and seal into the bore without fecking it up is nearly impossible regardless of tricks. It totally sucks and takes way too long.(Nice that beemerboneyard.com refunds these shit-kits and applies the cost against a quality slave cylinder replacement) 
• If you have ever taken a slave cylinder out of an r1150RT (which has even less room to work than the GS), you won't want to take a chance on a questionable rebuild shortcut, as getting the old one out and the new one fitted, as well as bleeding the system afterwards is a fiddley and time consuming project to put it mildly.

Lots of good how-too's on the slave cylinder replacement. But be prepared for it to take longer than expected, disassembling more than you think you should have to, and cussing more than your family, friends or even your dog should hear. Cocktails afterwards are generally warranted, as is Advil. Good luck!