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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: trek97 on October 08, 2016, 05:25:39 PM

Title: Found, Clutch boot leaking. 87 K75C
Post by: trek97 on October 08, 2016, 05:25:39 PM
Hey guys,
Found some oil on the floor and after some investigation, did a search and found this article seems to agree w what I got going here.

http://www.motobrick.com/index.php/topic,2883.msg16783.html#msg16783

But please take a look at my pics and if you agree/disagree please let me know. 

Plan to order new cup from bobsbmw.com at $45.35. 

Please let me know if you have a better resource.  THANKS!

(http://i1086.photobucket.com/albums/j449/trek97/BMW/clutch%20leak/IMG_0900_zpskdbaocwo.jpg)

(http://i1086.photobucket.com/albums/j449/trek97/BMW/clutch%20leak/IMG_0901_zpsvcsj4rgp.jpg)

(http://i1086.photobucket.com/albums/j449/trek97/BMW/clutch%20leak/IMG_0907_zpsohy8oxan.jpg)
Title: Re: Clutch boot leaking?
Post by: The Mighty Gryphon on October 08, 2016, 05:30:22 PM
I would very, very carefully remove the boot and check it closely for splitting before I spent $44 on a new one.  But that's just me.
Title: Re: Clutch boot leaking?
Post by: trek97 on October 08, 2016, 05:33:27 PM
I would very, very carefully remove the boot and check it closely for splitting before I spent $44 on a new one.  But that's just me.

Yep, looking for it in manual now.
Title: Re: Clutch boot leaking?
Post by: The Mighty Gryphon on October 08, 2016, 05:46:30 PM
If it is split, I would give it a very good cleaning with a paint prep degreaser like PrepsAll and give the split a shot of super glue or possibly the stuff they use for sealing retrofit CV joint boots.
Title: Re: Clutch boot leaking?
Post by: Martin on October 08, 2016, 05:54:14 PM
Finally we have something cheaper than the US clutch boot $25.00 Au plus $3.50 freight on Ebay. While you are doing it you might want to fit a grease nipple to your clutch arm, it keeps all the crud and water out.
Regards Martin.
Title: Re: Clutch boot leaking?
Post by: trek97 on October 08, 2016, 06:01:44 PM
If it is split, I would give it a very good cleaning with a paint prep degreaser like PrepsAll and give the split a shot of super glue or possibly the stuff they use for sealing retrofit CV joint boots.

I was kinda thinking that way.  If its pretty easy to remove/re-fit.  But if its a bear to get off/on there I may not want to do it again next month.


Finally we have something cheaper than the US clutch boot $25.00 Au plus $3.50 freight on Ebay. While you are doing it you might want to fit a grease nipple to your clutch arm, it keeps all the crud and water out.
Regards Martin.

Im finding very few parts like this on ebay here in the USA.  I was looking at the needle roller bearing in the manual and thinking.  Now why wouldnt they have put a zerk on that?  HA!
Title: Re: Clutch boot leaking?
Post by: trek97 on October 08, 2016, 06:05:15 PM
But, what Im really wondering is why there isnt a real seal somewhere behind that boot around the clutch push rod to begin with?
Title: Re: Clutch boot leaking?
Post by: Martin on October 08, 2016, 06:11:31 PM
Due to the size of it might be cheaper to get one from OZ via post. It might be worth contacting him. I am actually thinking about getting one to add to my collection of spares.  http://www.ebay.com.au/itm/BMW-Clutch-Actuation-Pushrod-Rubber-Gaiter-K75-K100-K1100-/142098201573?hash=item2115b67be5:g:DhwAAOSwEjFXc8YK
Regards Martin.
Title: Re: Clutch boot leaking?
Post by: Inge K. on October 08, 2016, 06:15:02 PM
Also check that the clutch is correct adjusted.

If the arm have to much angle from where it should contact the sealing surface on the boot,
the spring inside the boot won't be able to add a even pressure all around in the boot...against the lever arm.
Title: Re: Clutch boot leaking?
Post by: Inge K. on October 08, 2016, 06:16:42 PM
But, what Im really wondering is why there isnt a real seal somewhere behind that boot around the clutch push rod to begin with?

It is.....inside the end of the gearbox shaft......to prevent the gearbox oil from reaching the clutch.
Title: Re: Clutch boot leaking?
Post by: trek97 on October 08, 2016, 06:26:08 PM
It is.....inside the end of the gearbox shaft......to prevent the gearbox oil from reaching the clutch.

I have a lot to learn about these BMWs.   :dunno

So is this what you are telling me?  I have a seal deep inside there leaking?  and the oil is running down the push rod to reach this boot?

Title: Re: Clutch boot leaking?
Post by: trek97 on October 08, 2016, 06:28:26 PM
Its looking like I got to pull the exhaust off.  To get the pivot pin out.  ugh!
Title: Re: Clutch boot leaking?
Post by: trek97 on October 08, 2016, 06:31:30 PM
Due to the size of it might be cheaper to get one from OZ via post. It might be worth contacting him. I am actually thinking about getting one to add to my collection of spares.  http://www.ebay.com.au/itm/BMW-Clutch-Actuation-Pushrod-Rubber-Gaiter-K75-K100-K1100-/142098201573?hash=item2115b67be5:g:DhwAAOSwEjFXc8YK
Regards Martin.

Heck $25 AU cnoverts to $18.97 US.  I bet shipping is high and would take forever to arrive.
Title: Re: Clutch boot leaking?
Post by: The Mighty Gryphon on October 08, 2016, 07:04:34 PM
Just checked the listing.  $24.05 US for shipping to U.S.  No reason to buy from this guy.
Title: Re: Clutch boot leaking?
Post by: trek97 on October 08, 2016, 07:39:54 PM
Got things as clean and dry as I could.  Bout a 1/2 a cup of mucky gravel and sand in there.

Couldnt find any obvious tear in the boot from this angle. 

Tucked a couple white kleenex under the suspects.  Ill check back in the morning.

(http://i1086.photobucket.com/albums/j449/trek97/BMW/clutch%20leak/IMG_0918_zpsc3t3od7o.jpg)
Title: Re: Clutch boot leaking?
Post by: trek97 on October 08, 2016, 07:45:08 PM
Hey Martin the grease zerk is a super idea!
Title: Re: Clutch boot leaking?
Post by: Martin on October 08, 2016, 10:36:38 PM
$24.05 seems awfully dear for something you could just stick in an envelope and post. :dunno
Regards Martin.
Title: Re: Clutch boot leaking?
Post by: Martin on October 08, 2016, 11:06:02 PM
Just checked Ausralia Post prices to US                                                                                                                                 Use your own envelope
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Title: Found, Clutch boot leaking. 87 K75C
Post by: trek97 on October 09, 2016, 07:03:30 AM
Also check that the clutch is correct adjusted.

If the arm have to much angle from where it should contact the sealing surface on the boot,
the spring inside the boot won't be able to add a even pressure all around in the boot...against the lever arm.

I checked and found clutch was out of adjustment, THANKS, Inge K! (78mm)

So I got it set at 74.6mm, re-set the rod push bolt at the lever and free play at the control. The boot now looks to fit a bit better.
Also lubed the barrel.

The oil smells of gear oil.  So apparently that is completely normal as there is no inner seal to prevent this.  Though there is an o-ring in there that could be bad.  Im not exactly clear what the o-ring does...maybe its what keeps the oil from traveling into the clutch disk?

Got things dried out again and gonna wait and see if the mis-adjusted clutch was the culprit. (deforming the spring and not applying even pressure around the boot OR the boot is just showing its age and needs replaced.)   

I will report back later.
Thanks guys.

(http://i1086.photobucket.com/albums/j449/trek97/BMW/clutch%20leak/IMG_0928_zpsotafulao.jpg)
 
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: Motorhobo on October 09, 2016, 07:38:25 AM
At the recommendation of my buddy Mike B who was a BWW mechanic in the classic K era, I put a small dab of blue RTV sealant at the joint between that boot and the clutch arm.
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: trek97 on October 09, 2016, 07:53:33 AM
At the recommendation of my buddy Mike B who was a BWW mechanic in the classic K era, I put a small dab of blue RTV sealant at the joint between that boot and the clutch arm.

Sounds like a good idea.  If I find it needs to be repaired/replaced I will do that.
Thanks
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: Inge K. on October 09, 2016, 07:58:02 AM
The oil smells of gear oil.  So apparently that is completely normal as there is no inner seal to prevent this.  Though there is an o-ring in there that could be bad. Im not exactly clear what the o-ring does ...maybe its what keeps the oil from traveling into the clutch disk?

Where is this o-ring located?
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: Inge K. on October 09, 2016, 08:02:19 AM
At the recommendation of my buddy Mike B who was a BWW mechanic in the classic K era, I put a small dab of blue RTV sealant at the joint between that boot and the clutch arm.
Sounds like a good idea.  If I find it needs to be repaired/replaced I will do that.
Thanks

+1. I've also used this metod on a couple of this boot that haven't been so cooperative.
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: trek97 on October 09, 2016, 08:05:02 AM
If the clutch adj doest do the trick maybe I will pull it and give it a soak in Wintergreen oil and try the RTV.
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: Inge K. on October 09, 2016, 08:25:59 AM
The oil smells of gear oil.  So apparently that is completely normal as there is no inner seal to prevent this.  Though there is an o-ring in there that could be bad.  Im not exactly clear what the o-ring does...maybe its what keeps the oil from traveling into the clutch disk?

Where is this o-ring located?
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: trek97 on October 09, 2016, 08:48:09 AM
Where is this o-ring located?

All the pics of the thing kinda stink.  But maybe where the rod meets the diaphragm spring? 

Ive read 3 manuals and still its not super clear to me.  How the trany oil gets on the rod OR what stops the oil from getting on the disk???

#11 on the Clutch pic.
http://store.bobsbmw.com/microfiche/BrowseParts.aspx?GroupName=Clutch&MBike=51741&GroupID=21
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: trek97 on October 09, 2016, 09:02:44 AM
To me it kinda looks like the rod runs through the transmission input shaft?  which has seals on both ends.
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: Inge K. on October 09, 2016, 09:20:08 AM
#11 on the Clutch pic.

That prevents motor oil from reaching the clutch. ...becomes brittle after some years, ...and start to leak.
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: Inge K. on October 09, 2016, 09:22:30 AM
To me it kinda looks like the rod runs through the transmission input shaft?  which has seals on both ends.

The pushrod goes through the input shaft, but it's only a seal in the rearmost end, between the shaft and rod.
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: trek97 on October 09, 2016, 01:39:02 PM
That prevents motor oil from reaching the clutch. ...becomes brittle after some years, ...and start to leak.

The pushrod goes through the input shaft, but it's only a seal in the rearmost end, between the shaft and rod.

Ok cool and thanks.  Well, thank goodness its not MOTOR OIL leaking out.  Definitely smells and consistency of 90wt.

The good news...atleast the oil shes leaking is clean.  Arrgh.

The bad news...Adjusting the clutch has definitley slowed the leak by about 90%.  But not cured it.

So, I will see about pulling it apart this winter and fixing it then. 

I want to get through this maintenance/clean up and go for a ride before the snow flies!!!

Thanks for all the help Inge K and the rest of ya'll.

The rest of my goings on is over here...

http://www.motobrick.com/index.php/topic,9050.msg71598.html#msg71598
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: Inge K. on October 09, 2016, 02:01:59 PM
The good news...atleast the oil shes leaking is clean.  Arrgh.

The bad news...Adjusting the clutch has definitley slowed the leak by about 90%.  But not cured it.

Maybe a good cleaning of the surfaces between the boot and the arm is all that is needed....
only a few small particles would be enough to start a leak.
It is two or three circular ridges on the boot to aid the sealing.

Is the oil level in the gearbox correct .....?....it should be much lower than the shafts.
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: trek97 on October 09, 2016, 03:25:45 PM
Maybe a good cleaning of the surfaces between the boot and the arm is all that is needed....
only a few small particles would be enough to start a leak.
It is two or three circular ridges on the boot to aid the sealing.

Is the oil level in the gearbox correct .....?....it should be much lower than the shafts.

Fingers crossed, a good cleaning and a dollop of rtv is all it needs.  there was a bunch of sandy small gravel bits up in there.

Havent got to the gear box yet. Need to make a dipstick, as she didnt come w tool kit.  Bike is still on the jack.  Working on scrubbing the swinger and getting it buttoned up.  Ready for oil, tire and brake adj.
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: Laitch on October 09, 2016, 05:06:54 PM
Need to make a dipstick, as she didnt come w tool kit. 
Information in a few posts here. (http://www.motobrick.com/index.php/topic,4836.msg30280.html#msg30280)
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: The Mighty Gryphon on October 09, 2016, 08:35:12 PM
One comment regarding the clutch boot leak and the clutch cable adjustment.  On my '94 K75RT, when the clutch was adjusted for the 75mm free length at the end of the cable it allowed the arm to ever so lightly contact the muffler.  This resulted in an intermittent clanking at about 2000 rpm and above which was really annoying and took quite a while to locate.   Be aware that this is not an issue on all K75 bikes, as my S model does not have the problem, and yours may not have it either.  I'm only tossing this out as something you might want to check.

To see if you will have an issue here, pull the clutch lever all the way in and let it snap out.  If you can hear the arm hit the muffler, shorten the free length slightly.  It only took about 2mm for an adjusted length of 73mm instead of the 75mm specification to stop the noise on my bike combined with a bit of tweaking on the muffler mount to eliminate the clank. 

If you don't want to shorten the cable's free length, I suppose you can take a hammer and put a shallow dent in the muffler where the arm hits it. 
Title: Re: Found, Clutch boot leaking. 87 K75C
Post by: trek97 on October 09, 2016, 09:22:55 PM
One comment regarding the clutch boot leak and the clutch cable adjustment.  On my '94 K75RT, when the clutch was adjusted for the 75mm free length at the end of the cable it allowed the arm to ever so lightly contact the muffler.  This resulted in an intermittent clanking at about 2000 rpm and above which was really annoying and took quite a while to locate.   Be aware that this is not an issue on all K75 bikes, as my S model does not have the problem, and yours may not have it either.  I'm only tossing this out as something you might want to check.

To see if you will have an issue here, pull the clutch lever all the way in and let it snap out.  If you can hear the arm hit the muffler, shorten the free length slightly.  It only took about 2mm for an adjusted length of 73mm instead of the 75mm specification to stop the noise on my bike combined with a bit of tweaking on the muffler mount to eliminate the clank. 

If you don't want to shorten the cable's free length, I suppose you can take a hammer and put a shallow dent in the muffler where the arm hits it.

Thanks and just checked it.  Mines not even close.  I can squeeze my pinky finger tip in between there.