rear main seal install

[cy7878]

Sorry if this came up recently. I did do a search here and Google and got mixed answers. 

What I need to know is if the new rear main seal needs to be soaked in oil for any length of time on the K bikes as well as be "preshaped" by having it fit around the clutch bell.

I came across Don's old 2010 article on r/5 and that says to soak the r/5 seal in oil.
I asked the parts people, they said it goes on dry.

I have already ruined one $32 seal and would prefer to not experiment.

BTW my seal drift (tool)  with the 111 630 part number also looks different.  There is a inner spacer thing and no 0.5mm lip on the outer cup..... I'll post picts when I get home.  thanks.

[cy7878]

Also, I got a new hex nut and didn't see the part about the washer.  Has anyone re-used the washer?  I recall on MOA forum, Don told me the hex nut may be reused, but since that site is still down, I can't look up to see what he said about the washer...

Thanks

[cy7878]

Update:

I got the main seal drift.  I learned 2 things:

1.  it's not idiot proof.
2. I'm an idiot.

I thought I can just pound the center and the seal will just be aligned.  Even with the tool, there is actually a lot of adjustment involved which I failed to do.  I still managed to screw up my second $30 seal by driving part of the edge flush with the engine casing and half of the seal being in spec.  So the whole seal is still not in place.

[cy7878]

So basically the 2 parts of the tool, the small part goes over the engine output shaft.  It buffers the distance the big part/driver can be pounded, using actually the main output shaft.

If I was actually smart, I should have still pounded the edges slowly while checking the fitment all the way around.

[cy7878]

So instead of pulling the seal, I wanted to see if what I have will leak.

So I placed the clutch bell, O-ring, washer and torque the hex nut the 2 times as per Haynes manual.

I hooked up the computer and the battery.  Connected the exhaust.  Filled the engine with oil.   Hand held the starter and pulled in the clutch lever and basically fired up the engine to watch for leaks.  After running the engine for 20 minutes, with periodic bursts in RPM and watch the radiator fan come on, I can say I see no leak at this time.  I will see if there is any leak in the morning.

I suspect if there is no immediate disintegration of parts, I'm half way clear.  I don't know if the seal not being placed perfectly will last another 26 years or 30k miles, which the first one did. 


Feedback appreciated.

[cy7878]

can't find the video I took, but here is a pic.

[JamesInCA]

Not that it quite matters at this point, but that doesn't appear to be the current tooling. See: http://www.motobrick.com/index.php?topic=1350.0 and http://www.bmwmc.net/catalog/2798.pdf for the BMW bulletin.

Can you non-destructively remove the seal and re-seat it?

I'm wondering if having it slightly cockeyed will last. It seems to me that its elasticity might keep it sealed briefly, but perhaps not very long once it's subjected to running stresses. If it can't be removed for re-seating, it might be better to drive the whole thing flush than to leave it crooked.

[cy7878]

Thanks for the reply.  I looked around on google and saw that having cocked seal may cause increased operating temperature and you're right, the seal may fail early. 

The issue I see driving the seal flush is the lip may then miss the shaft and not form a seal on the back end.  I may bite the bullet and pull the seal out and get a new one to try again.  Hey, it's only money, right...

Has for the tool, I doubt the dealer will order old tool.  I think the 2 piece design is the current one.  Had I actually done it right, the seal lip will be .5 mm protruded.   When I pick up my gearbox tomorrow, I will get another seal.   

[jetpoweredmonkey]

I wouldn't overthink this one too much - here's my caveman method for the seal install, no fancy tool needed.  Leak-free 2000 miles later.  I did go around the diameter of the seal with a depth micrometer when I was done and it was pretty darn straight.  Just take your time, tap and check, make small adjustments, use assembly grease of your choice.  It's a rubber seal - no need to soak in oil, just a nice bit of grease inside the sealing lip to keep it sliding easy when you start it up.  Make sure the spring gaiter is in place behind the lip, but there is no need to "form" it to anything.

http://www.motobrick.com/index.php/topic,3216.msg20251.html#msg20251

As for the washer under the flywheel nut, I did replace mine but I really don't think it was needed, it suffers no damage from being installed as long as you didn't somehow scratch it up when removing it.  I did find that the thrust washer behind the flywheel was broken on my bike, it's a large 1mm thick washer made of plastic.  I don't think it's common to find it broken, but check yours well.

[jetpoweredmonkey]

Also, if I remember right, that big nut is a one time use locking nut - I WOULD replace that.  Cheap insurance against doing a big job twice.

[cy7878]

Thanks to all for the input.

I was at the dealer to pick up a part and thought, oh why not and bought another seal.

pop the cocked one out and placed this new one.  The mandrel helps but was slow to get the seal seated.  I used the clutch bell to drive the seal in as I did the very first time.  Once the seal is in most of the way, I used the mandrel (BMW tool pictured above) to pound the rest of the way.  The end result is much more uniformed "lip" around the seal.  I didn't see any obvious deformity on the seal itself.  Call it the day and bolted back a new rubber O-ring, torqued it with the old nut to 100 ft-lb, loosened it and replaced the nut with the new one and re torqued it to the second stage per haynes manual.  Then placed back the clutch and called it the day.  Now just waiting for my gear box to come back from the dealer to bolt that back.

I should have listened to Don on BMWMOA telling me to leave the main seal alone.  $80 for the tool and 3 seals each costing $37 and 2 O-rings later, I'm probably where I was.

[JamesInCA]

Wait ... you have a dealer, who has things in stock, that you can just "pick up"?

[cy7878]

Yeah. BMW San Diego.  They have most of the "maintenance" items in stock (washers and seals). Stuff they don't have they usually get within 1-3 days. 

They are 7 miles away from my work.  I'm trying to win a price for most consecutive days going there.  I'm at 8 right now.  I'll be there tomorrow for the gearbox and Thursday for the clutch boot clamp.

[Fliegenziegel]

Chuck
My engine seal appears to be leaking based on the evidence of oil from the outlet hole between the engine and transmission. Wondering if you want to sell the tool set for installation. Post on eBay and let me know?
Overall I am grateful for your documentation of this apparently daunting service issue.
Still riding?

[Laitch]

Chuck
My engine seal appears to be leaking based on the evidence of oil from the outlet hole between the engine and transmission. Wondering if you want to sell the tool set for installation.

Go to this post and click on its links.
http://www.motobrick.com/index.php?topic=7833.0

The o-ring might be all that's leaking. You sure can't tell from looking at the weep hole. Many people replace both when they get in there; some only replace the o-ring if that's the only leak point. There is video documentation on this site of how to get to the seal. 

[Fliegenziegel]

Thanks!
Ingenious solution for the seal installer! 


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