Hello colleagues,
I'm restoring a 1990 K75, 47Kmiles. Some 43Kmiles were put on it between 1990-1996. Since then it apparently was parked out in the Avenues in S.F., i.e. lots of sun and salty sea breezes. Result is that everything is totally corroded. The bike was running when it came to me albeit even if the brakes were not exactly there. But I've powder coated the frame, taken the engine, tranny, rear end down and cleaned the corrosion off. Now ready to start re-assemblying except for one small thing.

Gentleman who I bought some needed parts off of strongly recommended that I renew the "O" ring that sits under the clutch securing nut. Engine side of the clutch. It's the one that gives everyone difficulty getting the clutch off. So I obtained the "O" ring, some replacement wavy washers and started today. Problem is removing the 6 allen bolts that hold the clutch together. Not surprised though most of the bolts I've dealt with on this bike have come out fairly easily. Holding the clutch still, the first allen bolt partially rounded out on me. Apparently this is where I actually have corrosion on a bolt.

Issue: should I:
1. forget the "O"ring and button it all back up and reassemble bike. Lots of work left to do.
2. Or soak bolts with WD-40 or Liquid wrench, get one of those rip apart bolt tools and see if I can actually move those suckers. All for an "O"ring which as near as I can tell was working when I drove the bike last.

Wisdom appreciated.

The six screws and washers have to be replaced if disturbed as does the main retaining nut and washer.

The screws are steel into the aluminium clutch carrier and you will have the usual electrolysis if it's been damp in there.

Best thing is heat. A hot air gun is enough. Play the heat on the clutch carrier as the ali will expand faster than the steel screws.

If the allen head rounds out, bang in a Torx key socket. As I said, the screws are one-use and can be sacrificed.

They are not done up (or shouldn't be) to a very high torque value. You'll be fighting the electrolysis rather than anything else.

The O-ring can be difficult if you try to remove it in one piece. Give us another shout once you get that far if you're having problems.

WD40 is rubbish as a releasing agent (because that not what it's meant to do). Try windscreen de-icer. Cheap and effective.

Thanks MikeP,
Hint on heating worked fine on all but the one. Unfortunately my local hardware store doesn't carry any torx larger than T40 and that's not quite big enough. Tried the usual dodges of vice grips and a cut down ease out. So I'm out looking for a tool to fit in there and allow me to pull the one last bolt.
best regards
J.

Use a good sharp drill and drill the head off. use lubricant un the drill and take your time don't let the drill get hot.
Its a 7mm thread so an 8mm, 5/16" drill will work fine.

Update, I went out and bought another T40 and T45 Torx but neither one will catch and turn it. Still heating every time I try. Then went down to Sears and they had a kit to remove studs/bolts. Took it home and tried again (I really don't like beating on the clutch so I wanted the most grab and turn solution). Well that didn't work either and now I'm out $36. on tools that aren't getting the job done. (It's Sears and I'll try to take them back with complaint).

RicK G wrote:Use a good sharp drill and drill the head off. use lubricant un the drill and take your time don't let the drill get hot.
Its a 7mm thread so an 8mm, 5/16" drill will work fine.

That looks like what's next. I tried the old vice grips of course. No success either. Would it make sense to try my dremel and square off the sides of the bolt head, possibly to fit a small socket over it. Trying to think if anyone has square sockets. Probably not.
 
But if I take Rick G's advice and drill the head off is that going to leave enough to grab with a vice grip? And what about my favorite non-tool easeouts? If I'm drilling down into the head maybe an easout would make sense before taking the head completely off? Oh well, I'll sleep on it and maybe tomorrow will be happier. Still need to make the run across the bay bridge to S.F. and get the bolts. If they have them. All for a stinking "O"ring.

Suggestions always welcome. Thanks and then tomorrow.

Rick's solution is probably the easiest and quickest.

Don't worry too much about what's left of the screw because once you have the clutch carrier out you'll be able to work to remove what's left with it somewhere more convenient (even take it to someone else to do).

This may not happen but it's worth mentioning:

Getting the clutch cover off may not be straight forward if the damp has got in there. The dowel pins are steel and I once spent the best part of a whole day jiggling and levering to free one point that had corroded. Frustrating as hell because there's so little wriggle-room inside the bell-housing.

MikeP wrote:Getting the clutch cover off may not be straight forward if the damp has got in there. The dowel pins are steel and I once spent the best part of a whole day jiggling and levering to free one point that had corroded. Frustrating as hell because there's so little wriggle-room inside the bell-housing.

Just so I understand your description, take out the 6 bolts (maybe cut the one) and then?? I assume you're referring to pulling the outer housing cover off. And from the diagrams it appears the pins are a part of it. Is there anywhere you can put a pry? Or any magic to invoke to shake it loose? Rotate the clutch and try to pry it? Or did you mean something else by "levering"?
thanks
J.

jjefferies wrote:
Just so I understand your description, take out the 6 bolts (maybe cut the one) and then?? I assume you're referring to pulling the outer housing cover off. And from the diagrams it appears the pins are a part of it. Is there anywhere you can put a pry? Or any magic to invoke to shake it loose? Rotate the clutch and try to pry it? Or did you mean something else by "levering"?
thanks
J.

Pretty sure you got it right J.
Stupidly long post removed in favour of links to existing posts.

Read HERE
and HERE

My only comment is I had success with a claw hammer. Bit by bit round and round.

There is enough to grab with vice grips and I have found that the stub usually comes out with your fingers, I have only ever had one that was at all tight.
When you get the clutch apart check the steel plates for dishing I have found a lot that are dished and unuseable.
With a 75 I did a while ago the steels were dished but the plate had worn to fit so I confidently put it back together and it has been fine but you cant put a new plate in as it will only touch on the outer edge and slip.
The O ring is actually easy to get out if you sharpen a small cheap screw driver and use it as a chisel to cut the O ring up into 4 or 5 bits and it almost falls out.
I have been using new bolts but not OEM as they are too expensive. I get 7mm x 35mm hex head and 1/4" shake proof washers then cut the bolts down to the correct length and they are easy to get out and can be reused. There is plenty of room for the extra length of the head and if you want to you can use full depth socket head bolts, why the hell BMW  saw fit to use the shallow head bolts is beyond me.  7mm can be hard to find but they do exist.

As roskko says: yes.

The pins are on the cover plate and locate it and the pressure plate on the clutch carrier. Sometimes they are reluctant to let go of their grip.

It doesn't always happen. I just thought that it might be best to mention it so that you could dose them with a releasing agent before you start to pull the clutch assembly off.

Thanks guys. Photos always make it easier to see what is meant. But l intended to keep this as simple as possible. AFAIK, the clutch "was" in working order. Will look it over and check the thickness etc. But the whole business about replacing all the seals... Isn't that a bit of overkill? I understand that true BMW fanatics can be that way. But I'm in the "if it ain't broke" section of the choir. And feeling somewhat anal about going to all this trouble over an "O"ring that as far as I can tell wasn't a problem. 

Sooner or later I'm going to be getting back to the main issues of fixing what's obviously bad, the paint, the brakes, the overwhelming corrosion, the fungus growing on all rubber parts.

thanks
J.

jjefferies wrote: And feeling somewhat anal about going to all this trouble over an "O"ring that as far as I can tell wasn't a problem. 

 It's just good "housekeeping".

That O-ring is prone to becoming brittle and that in turn allows oil to contaminate the friction plate.

It's far better to whip it out and pop a new one in now when you are working on the bike anyway than have to do it if it fails later (and have to replace the friction plate etc).

jjefferies wrote:But the whole business about replacing all the seals... Isn't that a bit of overkill? I understand that true BMW fanatics can be that way. But I'm in the "if it ain't broke" section of the choir. And feeling somewhat anal about going to all this trouble over an "O"ring that as far as I can tell wasn't a problem. 

thanks
J.

The service life of a viton seal is 8 years, if you cant for absolute sure it has been replaced in the last 5 years then it is a very good idea to replace the rear main seal as a matter of course. It is at least twice it service life old maybe 3 times and by replacing the O ring you WILL be disturbing it so you have woken the sleeping dog.
For a matter of $30 you can replace it and know it is OK or trust to luck that it wont leak but you have disturbed it and replacing it while you are in there will save you the time and trouble of going back in within 12 months.
I have worked on bikes for many years in a professional capacity and my stock of trade as a fitter is shafts bearings and seals.

RicK G wrote:

jjefferies wrote:But the whole business about replacing all the seals... Isn't that a bit of overkill? I understand that true BMW fanatics can be that way. But I'm in the "if it ain't broke" section of the choir. And feeling somewhat anal about going to all this trouble over an "O"ring that as far as I can tell wasn't a problem. 

thanks
J.

The service life of a viton seal is 8 years, if you cant for absolute sure it has been replaced in the last 5 years then it is a very good idea to replace the rear main seal as a matter of course. It is at least twice it service life old maybe 3 times and by replacing the O ring you WILL be disturbing it so you have woken the sleeping dog.
For a matter of $30 you can replace it and know it is OK or trust to luck that it wont leak but you have disturbed it and replacing it while you are in there will save you the time and trouble of going back in within 12 months.
I have worked on bikes for many years in a professional capacity and my stock of trade as a fitter is shafts bearings and seals.

Well, your argument makes sense. But I can't find anything labeled rear main seal on the diagram for the K75 clutch or engine in the BMW fiches.
http://www.maxbmwmotorcycles.com/fiche/DiagramsMain.aspx?vid=51741&rnd=04302013
 
Could you point it out?
J.

11 11 7 666 186  SHAFT SEAL - 50X80X10 0.09  1   $30.60

ibjman wrote:11 11 7 666 186  SHAFT SEAL - 50X80X10 0.09  1   $30.60

A picture being worth a thousand words, here's three thousands worth.   Item 6 

Well, I used Rick G's suggestion and it worked fine. A little cutting oil and a carbide tip and the head popped off. Then 20 minutes fiddling with wedges (breaking one screwdriver) the cover came off and I marked it all so the orientation can be restored. After all the drama rama I tried the cut off bolt with my fingers and lo and behold it unscrewed easily. Made you wonder why all the fuss.

Now it's finish taking it apart. Got the main nut off and I understand there's still a compression ring under the nut which I have yet to get out. Then the blessed "O"ring. Then the aluminum housing. Then ?? the rear main seal?

Fun part of the day was taking that stupid stud puller back to sears. They took it back without question but I thought to replace the broken screwdriver  with three more. Sales fellow asked if I had points with them and I said "What"? Turned out I did so I paid $1.32 for three of Sears finest lifetime warranty screwdrivers. Lifetime unless they break while being used as levers.

Go back to Sears & get some of these:
http://www.sears.com/shc/s/p_10153_12605_SPM2092138803P?PDP_REDIRECT=false

LOL

ibjman wrote:Go back to Sears & get some of these:
http://www.sears.com/shc/s/p_10153_12605_SPM2092138803P?PDP_REDIRECT=false

LOL

If it had been planned there were several things that might have appealed. But I had intended to buy the screwdrivers on my own dime when the salesman popped the question about points. Short of getting Snap-on or maybe Matco I have been a fan of Sears tools in the past. My wife has more Snap-on tools than I, though I do have a good Snap-on torque wrench. A concern though is that Sears is putting more Chinese made product on the shelves and less American made. One reason for getting the screwdrivers now. Actually I think I do have the set ibjman recommended. Main complaint being that the bits were held in place by snap rings which didn't work. But a little epoxy has made them much better.

Ooops, Just hi-jacked my own thread!

Will be another day before I can make the trip to get the rear main seal. But I think the clutch on this bike had been replaced. Using my vernier calipers it shows .54 cm of thickness, well within the tolerable limits.

Totally off the subject, retrieved a broken electric oven today. Intentions are to use it to heat small metal parts in powder coating. Bkgrnd: I was looking to powder coat the two covers and a couple of smaller pieces. Got a quote of USD $140. Crazy. So went down to Harbor Freight and bought their $60. powder coating outfit and $5. of powdercoating material. And now a free oven. If I can make it work without too much lost time it will be worth the effort. Ripped a bit of skin off two of my fingers getting the oven in the back of my wife's truck. You'd think after all these years I'd remember that sheet metal cuts nastily.

Will post again when I have further news about the clutch etc.

thanx
J

Hello, after a brief hiatus to put together a powder coating station (to be reported on later) and some armory (sword smithing) work, and receiving parts, I'm back at this clutch. O-ring came out sweetly after all the comments, as did the clutch housing and now I'm looking at the main rear seal which I think will come out easily enough. But normally when installing a seal I use a socket the same size to tamp the new seal down into place. But this sucker is 8 cm in diameter and I ain't got a socket that big.   Any suggestions as to how to put this in? I suppose one could lightly tap around the edges to slowly put it in. But I'd prefer something like the socket approach as a more intelligent solution and less likely to mess it up.

And BTW, the output shaft is kind of jiggly without the clutch housing being mounted. Is that normal? By jiggly I mean it's got some side to side play. Would have thought it would be very rigid. Shows that I've never taken one down this far before.

thanks
J.

Duh! I stand corrected the old one ain't coming out easily after all. Chisel work? Big vise grips and twist the puppy till it squeals?

Just lever the old seal out. If you don't have a seal puller then a pry bar or a screwdriver will do (with the usual caveats about not scoring the surface where the seal seats).

Lubricate the new seal well. Start seating it and once it will stay in place, slip the clutch carrier back onto the output/balancer shaft.

Use the old collar and nut to draw the carrier back onto the new seal to press it home.

After a few turns, remove it and check that it's seating properly, then return it and press it home.

It won't seat it fully but it will go in square and get it to the point that there's just a small amount of tapping with a wooden block and soft mallet to get it flush.

The output/balancer shaft lashes about quite alarmingly without the seal and clutch carrier in place. It's normal (like you I had to check that it was the first time that I replaced an output shaft seal).

Thanks MikeP,
Got it out of there with only minor damage to the lip. You gotta figure as soon as you reminded me of that that would be what I would scr*w up. But minor, A small round file cleaned it up and then an hour to make sure no particles found their way further in the engine. Tomorrow to install the seal.