Potential Clutch issue?

[riceburner]

Had an odd thing happen this morning, and it's not something I seem to remember reading about from anyone else before.

Towards the end of a 40 minute ride, I was riding slowly through traffic, in first, slipping the clutch for about 100 yards.

I then turned into a side turning and released the clutch to ride normally, then pulled in the clutch to change down, slowing for a speed-bump.

When I released the clutch the lever became loose. and the clutch seemed to stick in the disengaged position (as far as I could tell).

I had a moments utter confusion, managed to get the bike into neutral, rolled for a short distance, with the clutch lever still loose, and not engaged with the mechanism (as far as I could tell).

I pulled over and the bike stalled. So I restarted it, and the clutch was suddenly working normally again - albeit feeling a little stiffer than before.

I completed my ride to work (about 100yards) with the bike seemingly behaving normally.


Has anyone had anything similar happen??

I'm not hugely familiar with the clutch systems, the bike has 87,000 miles on, and while it has been apart in that time to replace the clutch (amongst other things), I've not been in there myself (and don't really have the resources/time to do so). I don't believe the clutch fluid has even been changed, I've certainly never done it!


Any ideas from someone familiar with the clutch mechanism about why the clutch lever could become "loose" like that?

[riceburner]

ok - further thinking has lead me to believe the master cylinder piston jammed temporarily.

It's the only situation I can think of that would lead to the clutch lever flapping freely.

[Buckster]

No expert here....and it's never happened to me...but I would change that brake fluid for your clutch. It should be done every other year at least. I change mine once a year.

[sweatmark]

Burner, if it were me, I'd replace the clutch slave as preventive/corrective measure. Wonky clutch action is possible tell-tale of clutch slave woes.

[riceburner]

Have spoken to my main dealer, and they reckon it's the slave too.

I got home absolutely fine with it last night, but this morning it got a lot worse - the bite point slowly moved back to the bars, and the lever got softer and softer.

According to the dealer - the push rod sometimes gets "stuck" to the clutch mechanism, and so spins at high speeds (as opposed to being free and not forced to rotate), and this can damage the slave piston.

Main problem is that slave cylinder assemblies are in very short supply over here. And they're not expecting to have one in until the end of Feb. (They have an R1150GS Adventure in at the moment with a similar issue).

So - I'm now wondering how I'm going to get home tonight! I've got an offer to being the bike in for the diagnosis at least - which will get me a loan bike to get home tonight. But logistically that doesn't really help.


What's actually required to remove the slave cylinder?

The other issue of course is that really - if the push rod is stuck to the clutch mechanism, that would need fixing as well, otherwise I'm just going to wreck the replacement slave cylinder in short order.

hmmm.

[MALIBU02]

Burner -

I have been addressing a sticky downshift on R1150R. I had a discussion with the service dept at BMW dealer,
There was discussion about clutch needing lube on the clutch end of the transmission spline shaft.
I asked how to determine if lube was really needed. He said to put the bike in neutral and release the clutch fast or let go of it with motor running of course. If there is a delay in the clutch engaging (you can hear it) then it probably needs lube.
Worth considering since your clutch did not release.

Just a thought.

[riceburner]

MAlibu - you might be right ther - It'll have to wait until I can get the bike to bits now.

Got myself (and bike) transported home on tuesday evening and am commuting on 4 wheels (booooring!)

[MALIBU02]

Good Luck Burner,

Let us know how it turns out.

[riceburner]

Cheers - Bled the clutch fluid today, and it brought the hydraulics back online a treat. Much easier than I expected it to be as well.

I'm going to swap the master cylinder piston (with seals & spring) to be sure - but the hydraulic bit seems to be working ok now.

Unfortunately - in testing the bike (without earplugs in) I realised that the clutch is screeching something awful. I'd been aware of the noise - but since I only ever run the bike with earplugs in I'd not realised how bad it was.

Spoke to the local indy mechanic and he reckoned (without hearing it) that the slave thrust bearing was probably shot, which naturally indicates the need for a new slave cylinder.

So I'm going to get hold of one, take the bike around to his, and he'll replace it, and show me how it's done for next time. I can at least do the master-cylinder piston myself!.

Hopefully that'll be it.....

[sweatmark]

Suggest you replace that clutch slave cylinder sooner rather than later... if the old slave was/is leaking DOT4 fluid into the clutch housing via clutch rod, and if that's the reason you lost clutch action, then you'll be back to spongy clutch lever soon... and have that much more fluid "interacting" with clutch disk and/or splines.

I've got a spare clutch slave purchased from Beemer Boneyard (http://www.beemerboneyard.com/21522335061n.html) that I can send to UK if none can be found. Let me know if you need it.

[grwrockster]

Hi there RB!

Sorry to hear about your clutch woes. It appears like everyone has pretty much covered the stuff I'd have headed straight for (i.e. the Slave cylinder). In fact, I'd suggest not messing with the bar-end master unless the slave doesn't do the trick first. Brake cylinders are finnicky little swines and best left alone unless you have to go in there (if it aint broke, don't fix it etc.).

The slave failing though was the reason I ended up stripping the clutch on my mates R1150R - the consequences of it leaking (and it sounds like yours might be) and the oil tracking the pushrod and contaminating the friction plate are serious and expensive, time-consuming remedies). If the master is found to be shot, then its easy to get at and there are not the serious potential fallout consequences there are with the slave end. Also, the fact that you were able to get it to bleed up and work at all is a positive sign that the master might be ok.

As for supply..... I know you've have a Rockster for years and probably know all the suppliers but (just in case) - have you tried Motorworks, Motobins or James Sherlock for a Slave Cylinder? I'd have expected one of these shops to have stock on the shelf.

I got my mates replacement Slave Cylinder (and clutch plate, bolts, etc.) from Motorworks. I think it was 50-odd pounds plus carriage (a year or so ago).

Good luck!

[riceburner]

Ok - to continue the tale....

The bike is currently sitting with it's arse sticking up in the air, air-box off and everything around the slave cylinder cleared away (photos to come).

Can I get the bugger off??

All bolts undone - plenty of slack in the hoses, I even removed the bracer-arm across the back of the engine cases to give me total access. The slave cylinder slid out (stiffly) about an inch, and has now stopped. When I tug on it, it feels as if I am tugging on a pretty strong spring. The slave cylinder itself looks clean from any leakage (I can see the sides of the cylinder - they're clean).

So - my current thinking is saying that the push rod is jammed up in the slave cylinder bearing AND welded to the clutch spring somehow!!

I'm going to have another go at tugging the slave cylinder off (I have a spare....), but if the push rod is stuck/welded/jammed at both ends, how on earth am I going to do this? Even if I split the clutch housing, I can't get anything apart with the push rod stuck at both ends! (I'm also really hoping not to have to split the clutch housing and pull the gearbox away because I am concerned about getting it all back together again!!- especially getting the splines all lined up correctly).

Any thoughts/comments/suggestions from anyone??

[sweatmark]

'burner-

If it's still working hours in UK, perhaps call "Steptoe" (ADV board member) at http://www.gsshop.co.uk/.

Otherwise, I'd just use brute force to remove that slave cylinder... and probably the clutch rod stuck to it.

Good luck!

[riceburner]

Why do I always get the weird issues.....



Split the Clutch housing yesterday, after my last post above, and indeed - the gearbox didn't want to come away.

Managed to give the thing a good tug, (didn't resort to a mallet, although I do have one), and it finally came apart. Luckily I had the foresight to put an axle stand under it - that thing is heavy!


I wheeled the drive-train away, and after managing to finally extract the slave cylinder came to the following conclusion:

The push rod was indeed stuck at both ends. It's friction welded itself solid to the inner bearing race in the slave cylinder, and somehow had become stuck to the actuation plate on the spring plate as well. (the slave cylinder was in perfect working order, except for the bearing).

I took a look at the gearbox splines and although they look like they've done 87K miles, they're ok (I think?) .



The splines in the friction plate obviously were fine (plate has done less than 30K miles).



While I was looking at the friction plate splines I noticed that the hole the push rod goes through in the actuation plate was out of alignment. I stuck my little finger in and discovered the actuation plate was flopping around loose.



So I dismantled the clutch and discovered that the actuation plate was really VERY loose on the spring plate. The 3 steel fingers on the back of the actuation plate were knackered.



I think what has happened is that some asbestos fluff had somehow got caught between the actuation plate and the push rod, and had helped the two lightly stick together.


You can just about make out the discolouration around the central hole in the actuation plate. When I first dismantled the bike there was a small bit of fluff of some sort lightly stuck there.

Along with the push rod welding itself at the other end to the slave-cylinder bearing it meant that everything wasn't spinning at the same speeds, and so the actuation plate was spinning at a different speed to the spring plate. This is most likely what was causing the god-awful screeching when the clutch was "out". The slightly quieter screeching when the clutch was "in" was, I suspect, the slave cylinder bearing continuing it's self-destruction. The only material in the slave-cylinder housing was very fine ground steel....



So - I'm now about to purchase a new spring plate, push rod, some moly grease, and all the other little bits, to go along with the new slave cylinder I bought last week!

oh, and some new inlet manifold seals which I discovered were both knackered too - no wonder it hadn't been running quite right:


More pics here : http://www.flickr.com/photos/rockburner ... 080960209/

[grwrockster]

Good pics RB, and good to see you've got to the root of the problem (it's horrible when you've taken it to bits and are none the wiser) - even better, nothing truly wallet-busting seems to be the problem.

From the pic it looks like your splines are fine too (perhaps what's said about the spline issue being a case of misalignment and being more prevalent in '01 & '02 bikes has merit then?). If it does, your tear-down would suggest that you've got a 'good un' given your bikes mileage and what, pushing on for 90k miles? I know that you don't baby it either.

I take it that (apart from when the clutch was done 30k ago) that you haven't 'spline-lubed' annually or at all either RB? If so, this would again lead me to go along with the idea that some bikes suffer from a manufacturing tolerance/assembly issue more than others. I know you've had 3 Rocksters (and one with Spline failure if memory serves, and didn't you have a similar slave cylinder bearing failure issue as well on one of your bikes?) so you have lots of personal experience with these bikes - I'd be interested to read your thoughts .

I think I'd be pretty happy overall with what you've found - your Rockster looks like with a bit of fettling she's good to go for many miles yet (mine at the same year as yours is a babe in comparison with just 31k miles under her wheels... I hope it does as well!).

All the best. G.

[grwrockster]

Oh... just another thought and quick question to throw out there on the 'Failed Slave Cylinder' front given RB's sounds like it decided to weld itself to the pushrod.....

Given the fact that the Slave has a bearing, and that bearing is pretty small and does a LOT or revolutions, would it be wise to consider swapping out a slave cylinder as a preventive maintenance measure? I've done the other standard service stuff (Valve Clearances, TB's, Oil & Filter, Trans & Final Drive Oil, Air Filter, Fuel Filter, Plugs, with Brake & Clutch fluid & bleeding yet to do, so I guess if I'm going to swap it, now's the time).

I've been toying for some time with changing the Slave before it failed as an idea for quite a while now for my bike (2004 Rockster, 31k miles) - thinking that at about 60 Quid and some spanner-work it's probably worth doing for the peace of mind (and if the original proves to be still ok it can serve as a spare). I have no idea if there is a projected 'safe' lifespan for the Slave Cyl - any thoughts?

[riceburner]

Never greased the splines at all (this is my first ever foray into the clutch housing). I don't know if Steptoe lubed the splines when he did the clutch 2 years ago, I would have thought so. The bolts were certainly well coppa-slipped.

I can see how a slight mis-alignment would cause the splines to wear prematurely, which is why I'm a bit concerned about being able to put it all back together properly. The alignment tubes in the cases should help with that, and the alignment rods I made up and screwed into place prior to sliding the gearbox off!

In regards to swapping the slave bearing as a preventative maintenance measure: yeah that might be an idea, but it wouldn't need changing more than once every 50,000 miles. Maybe whenever you change the clutch plates. Motobins do (I seem to remember) sell the thrust bearing individually. It would be a bugger to get out of the slave cylinder though.

I do think that the design where the push rod is pushed against the spring plate with no bearing surface whatsoever (just a chamfered face) is a little cheap though. Even if the push rod is supposed to be spinning with the plate, I'd still have some sort of bearing surface there. I'll be putting a tiny bit of moly grease on the push rod to help it out.

[sweatmark]

That's an interesting idea about somehow installing a thrust bearing for the clutch rod's contact with the pressure plate. Good improvement, alongside the idea of relocating clutch disc hub via a spacer ring in order to mate more splined surfaces and lessen the cantilever load on the transmission input shaft.

Didn't know that Steptoe had done your previous clutch work. Would be interesting to know if he's seen the welded clutch rod situation before.

Sending my admiration for digging into the bike without reservation!

[grwrockster]

RB,

If the misalignment theorists are right, then your crankcase dowels must be good as is, or you'd have spline wear long before now. So, when you stick it back together you should have no bother (you have as they say a 'good un' - I hope mine is too being of similar vintage!).

Again (if the misalignment theory is correct) and IF ; manufacturing tolerances or whatever created the issue most known/prevalent on 2001-02 bikes; the problem was known but never officially recognised by BMW, then..... surely it would make sense if the manufacturing error was quietly addressed in-house by BMW as well? Which would lead to the idea..... (allowing for some 'pre-fix' assemblies to trickle through after instigation of the 'fix', thus leading to some, but diminishing spline issues on post-'02 bikes maybe) there should come a point where all 1150 models should suffer a lot less from this malady? Your bike (and mine) being 2004 models should, in theory have much better odds of avoiding spline woes?

RB - I noted from your pics that your clutch line seems badly corroded at the bend off the Slave? My mates (2001 'R') clutch line was so bad in the same place we had to change it for fear it would rot through. The other thing (perhaps BMW's bean-counters alone can answer why) is that the (rubber as it was an 'R' not a Rockster) OE line actually costs more than the (relatively more complex) Slave Cyl! It might be cheaper to get a replacement made up?

[riceburner]

Yeah - that hydraulic line is pretty badly corroded.

I'm tempted to swap in another line - but currently that would be extra cost.
Now I'm happier about getting to the slave cylinder though, I'll get it replaced when I'm a bit more flush, it seems a fairly simple job. Motorworks sell an armoured version all made up - so will probably go with that option sometime later this year. Will be a nice job to do on a sunny summer's afternoon (moving soon to a house with an unpowered garage - so working on the bike in summer will be FAR preferable to winter!!)