Cleaning splines and question about the clutch

[BermudaBrick]

Fellow Brickers:

With the help of some guide pins that arrived today, I finally have my K75's transmission out and am working on cleaning all the splines in preparation for some fresh lube.  What is the best way to get them clean so I'm not creating a rubbing compound when I add new lube?  I have a pick and hook set, some old toothbrushes and some heavy-duty Simple Green (which is actually purple) and I also have denatured alcohol.  What should I use?  What do you guys do?

And a question about my clutch: Since I've made it this far, I'm considering replacing the friction disk (and apparently I should also replace the pressure plate and diaphragm spring?).  Is there any way to know if I should do this without dismantling the clutch?  The manual talks about testing the thickness of the friction plate, and I sure don't see any way to do that without unbolting the thing.  I don't want to mess anything up if I don't have to...

Thanks!
 

[Elipten]

Since you are in this far you should replace the seal at the engine rear.

First get some white paint and mark alignment on all the clutch parts so it can be aligned when reassemble.

Then take it apart and inspect.  There is some good how to on the site.

[K1300S]

Tooth brush,  small flat blade screwdriver,  and brake cleaner.

[F14CRAZY]

Tooth brush,  small flat blade screwdriver,  and brake cleaner.

That's what I use.

[Laitch]

Tooth brush,  small flat blade screwdriver,  and brake cleaner.

That's what I use.

:2thumbup: I have small wire brush I use, too.

And a question about my clutch: Since I've made it this far, I'm considering replacing the friction disk (and apparently I should also replace the pressure plate and diaphragm spring?).  Is there any way to know if I should do this without dismantling the clutch?  The manual talks about testing the thickness of the friction plate, and I sure don't see any way to do that without unbolting the thing.  I don't want to mess anything up if I don't have to...

You seem a teeeeny bit obsessive here, Bermuda. There's no way to measure the friction disc without unbolting the clutch pack and using an accurate measuring caliper. There's also no need to replace all that other stuff if you're not having drive problems. How many miles on the bike? 30K? If it were mine, I'd bolt it back up after I cleaned and lubed the splines if I didn't see signs of leakage. You already know it's not that big a deal to get to where you are now, unless you're doing it in a walk-in closet or on a sidewalk during monsoon.

What you don't want to do is over-lube it.

[BermudaBrick]

You seem a teeeeny bit obsessive here, Bermuda.

Obsessive?  Hmmm... I'd say "cautious".  The bike has 57,000 miles on it and I don't know if it is the original clutch or not.  I'd hate to disturb the clutch only to find that it is fine. I've never done this before so I'm concerned that my clutch reassembly skills are not up to the task and I'll introduce vibration and have to do all of this again.

What you don't want to do is over-lube it.

Yes indeed.  I've been watching Chris' videos and they've been very helpful.

[Laitch]

. . .  I'll introduce vibration and have to do all of this again.

You won't if you mark up each element of the clutch pack and bolt it together with a clutch alignment tool. Where's your sense of adventure? The outcome is bound to be better than being set adrift in an orange crate filled with chum in the Caribbean Sea. Still, 50K miles isn't too much for a well-treated K clutch and you'd probably get away with just bolting her up after lubing. It all takes nerve, to a greater or lesser degree, but then so does riding a bike at 70 mph surrounded by Facebook page updaters and Tweeters.

[Martin]

I had 140,000 kilometres up and a small weep on rear main seal, ordered a clutch plate as a precaution. When I replaced the rear main seal, I measured the friction plate only to discover, very little wear heaps of wear left. As I had to special order the clutch replaced it any way. If you are worried about clutch wear it would be silly to not do it when you are so close. I prefer to use a clutch alignment tool but I have known plenty of people who have done it by eye or with bits of rod, broom handles etc. The tool is available from the US and is not dear. There is also an excellent drawing with dimensions in the Haynes workshop manual, I made mine on a 60 yr old belt driven lathe. As per already stated you MUST mark the alignment positions.
Regards Martin.

[BermudaBrick]

OK, following Laitch's advice I put on my "sense of adventure" hat and took apart the clutch.  The friction disc measured right around 5.5 mm, so I'm good there (right?).  Does this look like normal clutch wear to you guys?  Anything to worry about?

[kris]

Bermudabrick, that looks good to my eye. I am easy on the clutch in any event. I now have 64,xxx miles on mine. Had it apart at 61,xxx. Didn't bother replacing it. Was concerned that rivets were close to the surface but that is, apparently, normal. I don't give mine a second thought. Might check it at the next spline lube...or not. Try to source the clutch bolts from a local jobber. No need to pay BMW prices for those things.
Put 'er back together and enjoy the ride!

[Scott_]

As long as you have it this far open, you best replace the clutch nut "o-ring". If it hasn't started leaking yet, it will very soon.
More often then not, they age and break and then leak. The higher the oil level in the sight glass above the center line, the more the tendency for the o-ring to leak.

I'd also clean the metal surfaces of the pressure plate and the housing cover. Looks to me like there has been some oily substance on them at some time. Acetone should clean them up just fine.

[rbm]

Clutch thickness is between 5.5mm (new) and 4.5mm (wear limit), so yours is excellent.  Nothing to worry about on the friction surfaces.  The splines look like they may be wearing to my eye; I think I see the mountaining effect on the top ones in the photo but that might be lighting.  Check them with a magnifying glass (I am probably wrong in my evaluation).

[F14CRAZY]

I replaced my disc a couple seasons ago as the splines were close to being shot. Yours still look really good

[BermudaBrick]

Clutch thickness is between 5.5mm (new) and 4.5mm (wear limit), so yours is excellent.  Nothing to worry about on the friction surfaces.  The splines look like they may be wearing to my eye; I think I see the mountaining effect on the top ones in the photo but that might be lighting.  Check them with a magnifying glass (I am probably wrong in my evaluation).

Hi Robert:  Yes, there is a slight mountain effect on the friction disc splines but nothing like the drive shaft splines!  I'll be leaving the clutch disc alone for now, other than cleaning and lubing before I put it back together.

As long as you have it this far open, you best replace the clutch nut "o-ring". If it hasn't started leaking yet, it will very soon.
More often then not, they age and break and then leak. The higher the oil level in the sight glass above the center line, the more the tendency for the o-ring to leak.

Scott_:  Yeah, shoot... I went back and forth on this since there is no oil in the bell housing and replacing it will require me to purchase a 30mm socket which I don't have.  When I called the dealer in my area to order replacement clutch bolts he told me the clutch nut had been superseded with a different part (and different size?).  Anyway, I decided not to do it... but perhaps I should.  It's just more money, after all  :musicboohoo:

[rbm]

Don't know how well stocked your tool box is.  Other tools that will be needed along with the 30mm socket is a good torque wrench capable of measuring 140Nm.  That's usually a 1/2" long handle one.  The 30mm socket is also used in several other areas of the bike so it's not a bad investment.  You'll have to find a way of centering the clutch; there are proper clutch centering tools sold for the purpose or you can adapt something as well (large magic marker for example).

Also, your clutch splines appear to be bone dry.  That may have contributed to their wear.  You may also have noticed that shifting gears was difficult.  Don't forget to lubricate the clutch splines on reassembly.

[BermudaBrick]

Don't know how well stocked your tool box is.  Other tools that will be needed along with the 30mm socket is a good torque wrench capable of measuring 140Nm.  That's usually a 1/2" long handle one.  The 30mm socket is also used in several other areas of the bike so it's not a bad investment.  You'll have to find a way of centering the clutch; there are proper clutch centering tools sold for the purpose or you can adapt something as well (large magic marker for example).

Yep, I've got the torque wrench and ordered the clutch alignment tool from Ken Lively (Polepenhollow Machine Shop), so I think I'm OK there.  The wrenching on my brick has certainly expanded my toolbox.  Not sure if my wife appreciates that, but... :yes

Also, your clutch splines appear to be bone dry.  That may have contributed to their wear.  You may also have noticed that shifting gears was difficult.  Don't forget to lubricate the clutch splines on reassembly.

I took those pictures after a thorough cleaning.  Everything was lubed with what looked to be Honda Moly.

Thanks, everyone, for your replies.

[Elipten]

I strongly recommend replacing the o-ring, nut, and bolts.  Cost is small compared to clutch disk and it will fail. Rear seal also a good option and then you will not have to service those items again for 20 years or more

[BermudaBrick]

I strongly recommend replacing the o-ring, nut, and bolts.  Cost is small compared to clutch disk and it will fail. Rear seal also a good option and then you will not have to service those items again for 20 years or more

Can anyone tell me where I can find the real seal on the fiche?  Does it sit behind the clutch housing?  I see an o-ring/seal looking thing marked as part #10, but #10 isn't present in the list of clutch parts.

Thanks!

[Laitch]

It's #11 at the right hand side of the diagram if you mean the rear seal alluded to in a previous post.

If you're following BMW's recommendations you're going to replace #8, #9 and the number twelves, too.

[BermudaBrick]

It's #11 at the right hand side of the diagram if you mean the rear seal alluded to in a previous post.

If you're following BMW's recommendations you're going to replace #8, #9 and the number twelves, too.

OK, I'm confused.  Elipten said "Rear seal also a good option" when talking about the nut and o-ring.  Is that o-ring the main rear main seal that is listed as #11?  I'm replacing the bolts and washers (6 each of #7 and #12 are on order).  If I replace #8, #9 and #11 then am I "set for another 20 years" or is there another seal I still need to replace? 

Thank you.

[rbm]

The O-ring sits on the output shaft, just ahead of the clutch pack.  The main seal is pressed into the engine block.  If you replace the parts you've indicated, including the main seal, you'll be good for another 20 years or until the O-ring dries out, whichever comes first.

[BermudaBrick]

The O-ring sits on the output shaft, just ahead of the clutch pack.  The main seal is pressed into the engine block.

OK, so is that #6 on this diagram?



Thanks.

[Laitch]

Yes.

[TimTyler]

Like Laitch says, that's the shaft seal part.

The clutch nut O-ring is #13 in this first image, and #11 in the second image.

Part # 11211460456  $1.84 US

[BermudaBrick]

And the saga continues... I had to wait for various parts to be delivered to my local dealer from Pennsylvania, but they arrived yesterday and I got to work this morning.  I managed to get the clutch nut off (pretty serious torque here!) and was presented with a confusing scene.  The existing seal looks quite different from what I received from the dealer.  Did I get the right one?  If so - great.  But how in the heck to I remove the existing seal?

Thanks for any pointers.