Oilhead clutch issues? Need advice from oilhead gurus

Discussion in 'Road Warriors' started by Bueller, Jun 26, 2006.

  1. Bueller

    Bueller Cashin? Super Supporter

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    Last year we bought a 2002 R1150 RT for my girlfriend. It was barely used, with only 5800 miles on it. I did the 6k service, flushed the brake system, bled the clutch hydraulics, and all has been well. As of today it has 12,100 miles on it.

    Yesterday morning I took the RT on an Ironbutt ride. For about 600 miles of the 1100 + mile ride it was fine. After sitting for what seemed like an eternity waiting to re-enter the states at the Buffalo NY/Canadian border I barely noticed the engine seeming to rev just a little quicker than the bike was accelerating, only while under full throttle. A couple hundred miles later I got on it pretty hard in 3rd gear and the engine definitely took off without moving the bike appropriately. I nursed it through the remaining 500 miles of the ride, hoping to get home without having to call a wrecker. Just before I got home it was getting bad enough to slip at 1/2 throttle.

    I've read a few horror stories about early 1150 cc oilheads, such as premature input shaft spline wear, leaking input shaft seals, etc. My girlfriend has decided the bike is too heavy for her, so I'm going to buy her a different bike, sell my LT, and ride the wheels off of this paid for RT. I dislike broken bikes, even more so when they leave me stranded. Thinking about all of that this morning I decided I wanted to have a look at the input shaft splines anyway, so I decided to take a crash course in Oilhead transmission removal:

    [​IMG]

    [​IMG]

    Took a little bit to figure everything out, but it wasn't too bad.

    The input shaft seal of the transmission is completely dry. The splines look great as well:

    [​IMG]

    However, when I removed the slave cylinder I got a whole bunch of gear oil mixed with what looks to be rust running out of the back of the trans:

    [​IMG]

    The clutch disc looks good and doesn't really feel oily:

    [​IMG]

    The pressure plate has a little bit of oil on it, mostly out towards the edges:

    [​IMG]

    [​IMG]

    Other than that little bit of oil and a hot spot or two, things don't really look all that bad to me:

    [​IMG]

    This picure of the clutch spring leads me to believe my slippage was caused by gear lube travelling up the release shaft and then getting thrown out onto the clutch disc:

    [​IMG]

    My questions are:

    1) Have I really found the problem?

    2) Will an oilhead clutch slip with such a minute amount of oil on the clutch disc or pressure plate?

    3) How is the gear lube getting into the slave cylinder hole, and how do I seal it so it doesn't happen again? There has to be more to sealing this thing than that silly little piece of felt on the clutch release shaft, isn't there?

    4) Can I just clean up the slave cylinder with brake cleaner to get rid of all of the rusty crud or should I replace it? I really don't want to do this job again for a while.

    5) Would you go ahead and replace the input shaft seal even though it isn't leaking and only has 12,000 miles on it?

    6) Based on the pics would you believe the clutch is slipping or would you look elsewhere, such as the driveshaft rubber coupler? I've been through a broken driveshaft on a 2000 RT and the symptoms are largely the same. Incidentally the driveshaft on this bike looks ok.

    7) Is there a particular way the driveshaft halves are supposed to be aligned before reassembly?

    8) Will you come over and put this thing back together for me? :lol3

    Thanks!
    #1
  2. Anorak

    Anorak Woolf Barnato Supporter

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    Replace the slave cylinder. It's shot. It leaked brake fluid onto the clutch. The mix of gear oil and brake fluid ate the clutch. Replace at least the friction disk and if you are a real mechanic replace the pressure plates and the spring as well. If your driveshaft is shot it smells strongly of burning rubber and the bike doesn't move. The drive shaft goes together with the u-joints 180 degrees out of phase. That piece of felt is the deal.
    #2
  3. Bueller

    Bueller Cashin? Super Supporter

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    I thought of that, but the fluid only smelled like gear oil. There wasn't even a hint of brake fluid smell, and to my knowledge the clutch fluid level hasn't changed since I last bled it.

    :dunno

    One other question - if the slave cylinder did cause this issue what do you think about drilling a "drain hole" in the tranny case right below the slave cylinder. I know some of the LT owners have done this figuring if the slave cylinder leaks at least it won't take out the clutch too.
    #3
  4. acejones

    acejones Long timer

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    I believe Fluorescentbrown is right. Replace everything in there. You don't want to go back in there for something you should have replaced.
    #4
  5. Steptoe

    Steptoe steptoe

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    If the slave cylinder was leaking, you'd have had other issues with the clutch operation.

    Always replace the pressure and cover plate, as well as the friction plate. The heat from a slipping clutch effects the surfaces of the pressure and cover plates. if you only fit a friction plate, it'll be OK for a few thousand miles, then will start to slip.
    #5
  6. Mully

    Mully Kineticist

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    Bingo! The oil is leaking past the clutch slave cylinder seal at the rear and migrating down the pushroad, where it's thrown out onto the spring and migrates outward to the edges of the pressure plate/disc. The "rust" you see is a mix of gear oil and hydraulic. If it were mine, I'd be tempted to replace the slave cylinder seal(s) and friction disc, and just clean up everything else; you're the eyes on the job, so its your call. Those high spots on the pressure plate worry me a little, too; a clutch job on an RT is such a bitch, I'd only want to go in there once.....I'd try an oil stone on it maybe; I've done that successfully on auto flywheels.

    And yes, it only takes a *little* oil or grease to make an Oilhead clutch slip. Dont bother asking me how I know that. :evil

    mully
    #6
  7. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    Sounds reasonable to me, though I would carefully evaluate whether or not you need to replace the pressure plates. Likely they can be cleaned up, lightly scored, and reused.

    Jim :brow
    #7
  8. Bueller

    Bueller Cashin? Super Supporter

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    I took the transmission and clutch parts to my friends at Holt BMW. The general consensus is the slave cylinder area of the trans was a real mess. The tech said he just did this same repair to one last week and it wasn't nearly as nasty. I wonder which came first? I suspect the slave cylinder leaked enough fluid to damage the input seal, causing it to leak gear lube into the slave cylinder hole. But who knows?

    They recommended I replace the input seal near the slave cylinder, the slave cylinder itself, the felt on the clutch rod, and the clutch disc. They seemed to think the pressure plates would be fine with a light scuffing.

    I ordered the parts, they'll be in tomorrow. the total was about 300 bucks. In the mean time I came home today and pulled the input seal inside the slave cylinder hole. It was a total bitch to get out. Now I get to sit back and wait for parts. I think I'll call BMW corporate and ask them if they think it's normal for a slave cylinder or input seal to fail and wipe out a clutch after only 12,000 miles.
    #8
  9. Jim Bud

    Jim Bud Long timer

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    These bikes like to be used, and yours had not been used...

    I'm willing to bet the clutch fluid sat for years without being changed and corrosion and dry seals are not good friends....

    I had my slave cylinder go at 20k miles and the bike was used....and I flush it with every oil/brake fluid change...never hurts to flush these guys...

    Put it back together and use it.....it needs to be broken in...:D

    Have fun.....

    BTW, make sure you remove the brake calipers and lube them while you have it down....if the rear pads are one-side-worn its a sure sign that they need lubrication....do the fronts too......the calipers get sticky if not used and lubricated....
    #9
  10. Bueller

    Bueller Cashin? Super Supporter

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    I put 1173 miles on it Sunday. Is that the kind of use you are referring to? :evil

    I've thought about that, but even considering the time issues it shouldn't have been as bad as it was. Even if the clutch fluid has never been flushed since new it was only a little over a year late when I did it. Based on what I saw when I opened it up and what the dealer suggested it had to have been leaking at least a little bit for quite some time.

    As for the brakes, I'm also doing the 12k service and a wheel circuit flush while it's apart, so I'll have a chance to look at the calipers. When I flushed the entire brake system last year everything looked fine.
    #10
  11. Jim Bud

    Jim Bud Long timer

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    is frequently not changed on a new bike....for a variety of reasons...and if only changed thereafter based on mileage....it can go a long time.....

    And the effects of moisture on the fluid slave cylinder can cause a lot of deteroration due to corrosion, etc....

    In addition, I'm suprrised at how fast the clutch circuit fluid goes dark in color when compared to the brake circuits.....heat?, moisture?, design?, not sure why...but it seems to be that way to me....

    That is why I have a easybleed on my clutch circuit too....quick and easy to flush along with the brakes...

    Cheers...
    #11
  12. Rad

    Rad Done riding

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    Here is the best advice yur gonna get....Do whatever Mully says:lol3 That advice has always worked for me with my Oil Heads :thumb
    #12
  13. Reprobate

    Reprobate Sarcasm Loading....

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    What does the clutch rod look like? And check the clutch rod bearing - you're there now anyway. I'd be tempted to put in a new bearing and rod - I bought my GS secondhand and the clutch rod failed after about 20K kilometers. The bearing had been damaged by overheating from a lack of slack in the clutch cable by previous owners.
    #13
  14. kbasa

    kbasa Being, human. Super Moderator

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    :nod
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  15. Bueller

    Bueller Cashin? Super Supporter

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    There is no clutch cable - it's hydraulic. If it was a cable actuated clutch I wouldn't be in this situation.

    I never had a hint of trouble out of the cable actuated clutch on my '00 RT. But I guess the move to a hydraulic clutch is supposed to be progress :rolleyes
    #15
  16. hogmolly

    hogmolly Dude

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    If oil/brake fluid is traveling down the pushrod, then wouldn't the input shaft seal be suspect? It's the one pressed into the input shaft of the transmission.
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  17. Bueller

    Bueller Cashin? Super Supporter

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    There are two input shaft seals on this transmission - one at the front near the clutch, and the other at the rear of the transmission, inside the slave cylinder cavity. Since that cavity was full of gear lube I can only assume the seal was leaking. I suspect the slave cylinder leaked enough brake fluid into the cavity to damage the input shaft seal, which caused that seal to leak gear lube.

    My replacement parts show up today. I had a hell of a time getting that rear input shaft seal out of the transmission without splitting the case. Hopefully there are no burs or nicks on the input shaft, but it is difficult to see down into that area. I suppose if it leaks again I'm going to have to split the case and have a look at the input shaft, but I really hope this is the end of it all.
    #17
  18. kbasa

    kbasa Being, human. Super Moderator

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    I've heard of slave cylinder failures in RTs before. Have you inspected it?
    #18
  19. hogmolly

    hogmolly Dude

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    Maybe we're talking about the same seal. I'm talking about the little seal that's inside of the input shaft. It seals the clutch rod and is behind the felt. I've only worked on GSs but I can't imagine they would put a little seal on the front side of the felt. This is the seal that gets screwed up if you push the clutch rod in from the back. You can pull the rod out of the back but you should push it in from the front.
    #19
  20. Bueller

    Bueller Cashin? Super Supporter

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    Now you have me a bit worried. I'm going to call the dealer and see if I'm missing something...

    *edit*

    Just spoke with the dealer, there is no seal pressed into the input shaft of the 6 speed transmission, at least not that he can see in the picture. There is only the little felt piece on the clutch pushrod. I'm not sure what good a seal on the inside of the input shaft would do anyway. Assuming the slave cylinder isn't leaking and the rear input shaft seal is good there wouldn't be any fluid there to migrate up the clutch rod anyway.

    :dunno
    #20