Clutch Slave Cylinder

[Beemer1150]

... back again after a move from the UK to SW France!

On the way to the English Channel ferry to bring the bike over here to France the clutch slave cylinder gave up the ghost - at 0600 in the morning!

Wonderful service by BMW dealers CW Motorcycles in Dorchester had me back on the road by lunchtime (but at a cost!) and on the night-time ferry.

At only 15,000 miles on an '03 bike I was surprised at the failure, but browsing the threads now we're settled here I found that this might not be an isolated incident.

Does this happen often, any guidence on why?

(PS it was worth it... almost empty French roads and 30 degrees in late summer are bliss! It's about 5 degrees now and the bike's under its cover in the garage, but they say Spring comes early here...!)

[Arbreacames]

What were the symptoms? (noisy bearing, no clutch, etc.) What was the problem (seal, rough bearing, overheat due bearing). Was the condition of the clutch fluid responsible?

Remember that your 30 degrees are not our 30 degrees! I was feeling sorry for you until I remembered too!

[CycleRob]

30C=86F
5C=41F


DOT-3, 4, and 5.1 brake fluids are extremely hygroscopic. Slave failures are almost always caused by absorbed moisture/water that goes to the low point (the slave) where it works it's dastardly deeds, 24/7/365, for years. Low mileage, low usage makes the chance for corrosive damage more likely, not less. The clutch should be thoroughly bled every year, need-it-or-not.

[Beemer1150]

Thanks all, I'll take Cyclerob's advice and bleed the clutch through annually - it was a proper job to replace, on any vehicle they seem to start with one component and then build the car or biike around it around it. Judging by the bill and the amount they had to remove I guess it's the slave cylinder on the R!

[Johan_SA]

Hi
I also experienced clutch failure on my 2002. I could see the brakefluide dripping out - very slowly. It turned out that it was not the slave cylinder that was faulty but the seal where the hydraulic pipe joins the cylinder that had come loose.

Apparently another common problem in areas where you have high humidity is that the steel part of the hydraulic pipe has a sheath over it. Moisture collects between the pipe and the sheath and then the pipe rusts through. I pulled the sheath up as far as possible and tied it down with a cable strap at the top to prevent water from entering the sheath and also to prevent the sheath from sliding down.

Johan

[awagnon]

Apparently another common problem in areas where you have high humidity is that the steel part of the hydraulic pipe has a sheath over it. Moisture collects between the pipe and the sheath and then the pipe rusts through. I pulled the sheath up as far as possible and tied it down with a cable strap at the top to prevent water from entering the sheath and also to prevent the sheath from sliding down.

I just tore into my '02 RT to lube the splines. I found hydraulic fluid dripping from the clutch hose where the rubber meets the metal part of the banjo connector at the slave cylinder. Called all over the US, and no dealer stocks the hose. Ordered one for $96 plus S&H. Ouch..!! Will take at least 7-10 days to get it. Bummer.....

[boxermania]

awagnon

You have the rubber hose variant....there is another option, maybe less expensive, look into the SS braided aftermarket hoses, for the future that is.

BTW, all of the newer models at least the Rocksters, are using these type.

[awagnon]

look into the SS braided aftermarket hoses, for the future that is.

Good idea. I should have thought of that. I may call the dealer Tuesday and see if he's already placed the order. Probably too late.

[MikeCam]

Rob, Al - might be a good time to post the link to (or write a newer post) about the clutch bleed. A fairly straightforward and user do-able procedure.

Where to find the clutch bleed hose? How to replace the hose plug with a bleed nipple (and which part number to find/buy/try)? The three handed, four eyed method for bleeding while not introducing air, the self-test and final check.

Maybe also (Phil) could clean up and re-post the clutch slave cylinder how-to that was here a few months ago.

[awagnon]

Rob, Al - might be a good time to post the link to (or write a newer post) about the clutch bleed. A fairly straightforward and user do-able procedure.

I vote for Rob doing it. I'm a just a novice.

[dnat928]

How timely. I just did the clutch bleed yesterday. The only snafu was the bleed nipples - at my first attempt to screw it in, it did not seem to fit and I did not want to force it. I went back to the BMW dealer where I bought them - they reassured me it was the correct one. On the second attempt, I got it going, but it was not easy. The pointed end contacted the fluid ball stop when I tried to thread it in, which means it was dripping fluid as I was working on engaging the threads. I just kept pushing and working to get a good engagement. Eventually, with the right amount of twisting and force, I achieved thread engagement, then used wrenches to get the correct amount of penetration. I used my vacuum bleed apparatus, then slowly pumped the clutch lever. Each pump caused the fluid level to drop a bit. Kept topping it up until new fluid was evident. Done!

[Beemeridian]

678

[awagnon]

I have a couple of bottles of brake fluid outside that are half full, have been tightly sealed, but are over a year old,
Are they still good,

No.

should I buy a new bottle just to be on the safe side

Yes.

[MikeCam]

Courtesy of Whaycoc from 2005...

"At the dealer they call it a "clutch bleeder" nipple.

Part number 34212330310

You must remove the plastic tubular thing around the end of the clutch hose (right side rear of bike up under the right passenger foot rest). Screw this nipple in and then use it as you do the brake nipples with the Mity VAc or other bleeding device. "

Courtesy of Sunbeemer from 2007...

"AND, the BMW clutch bleeder screw is part #34 21 2 330 310,
OR the Speed Bleeder for bleeding the clutch (at the filler adapter) is # SB1010S"

Courtesy of CycleRob, Phil and Al 2007...

"...the slave has gone south. That fluid should not be dark. I bleed mine about every other year and its always still almost clear.

DJ, you will have to take off the bottom end of the rear shock and raise the frame about a half inch to get the slave cylinder to slide out once you undo it. I would do this before I'd haul it to a dealer. Once it's out you can replace it with a new part or clean it good and put it back in, depending on its condition. After its all reassembled and the shock is back on, you just fill it back up with DOT 4 and bleed it out good. " Phil

"...clutch slave cylinder......the pressure you build starts leaking either out or back to the low pressure side, in the first case the level of the master cyl will go down, not so in the second case. Rebuild or replace. " Al

"The puzzle pieces are forming an answer to this question of why the clutch lever goes soft and dysfunctional. Besides the left HandGuard contacting the lever's ball end preventing it from fully releasing, can we point the finger at Mobil-1?

I had the same dead lever problem about 4 or 5 years ago. The clutch lever progressively went soft and the DOT4 system fluid got smelly and dark. The reservoir was full, dark with Aluminum glitter to it & rankisly smelly. I did a roadside bleed and recovered function. Then it did it again later on in the same ride. It turned out the upward migrating left HandGuard was not allowing the clutch lever to go to full release, somehow overheating the slave fluid to boiling.

I believe I was running Mobil-1 in the transmission back then. I changed out the Mobil-1 the next 6K service because I noticed it did not shift as smoothly as other heavier weight synthetics. I noticed a harsher "sting" of gear dog engagement as I was shifting. I continued to use Mobil-1 GL-5 in the rear drive because of it's low hand-spin rotational friction and noticeably cooler to the touch running temp. No other problems ever happened after the handguard repositioning and trans fluid change, now with 56,090 miles (90,268km].

To think that Mobil-1 swelled or softened the transmission seal(s), as some rumors say, makes me wonder how very right they are. I say "wonder" because no gear oil leaks have ever occurred on my bike.

Getting back to DJ's problem . . . . Being winter there, my advice is for DJ to take the clutch release system all apart for cleaning, diagnostics and selective replacement. Like Boxer said, the frame has to be loosened and lifted a little to get the clutch slave out, but it's not difficult, just simple multi-operation busy work that one person can do using tiedowns. There aren't many individual internal parts to the clutch release system, so erase your fears and dig in. You'll also be able to clean the (removed) rear shock and swingarm area really good. The 69MegaByte PDF file of the BMW manual walks you thru the process, but it does not spoon feed you. Internal snapring pliers are prolly the only special tool you'll need (to take apart the master cylinder and slave).

A few tips: loosen tight banjo bolts before dismounting the slave or M/Cyl. You can contact me and I'm sure Boxer (Phil] & BoxerMania (Al) if you get in a jam. We all have digital cameras, fast net access and (speaking again for Phil & Al) a willingness to help. DJ has lots of crappy cold weather indoor time and a very sick bike." Rob