Mono shock rear drive large seal leaking

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beemered
Posts: 16
Joined: Sun Aug 08, 2010 8:25 pm

Mono shock rear drive large seal leaking

Post by beemered » Sat Sep 16, 2017 7:41 am

Hello,
I need to change this seal as it has been leaking slightly for awhile.Any tips or Hints at removal and replacing without damage?I ordered a Lisle seal removal tool,anyone use one of these?
Also recommendations for cleaning brake shoes,I have brake cleaner,will use that first.Some say once contaminated replacement is in order.
thank you,Ed

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SteveD
Posts: 4064
Joined: Tue Aug 03, 2010 3:29 am
Location: Melbourne, Oz.

Re: Mono shock rear drive large seal leaking

Post by SteveD » Sat Sep 16, 2017 9:44 am

Maybe soak the shoes in brake cleaner or shellite overnight, then give them a good soapy wash? See how they go after a good warm up then some test braking.

Is the shock oem or something else? I thought the oem were essentially disposable?
Cheers, Steve
Victoria, S.E.Oz.


1982 R100RSR100RS supergallery. https://boxerboy81.smugmug.com/
2006 K1200R.

Rob
Posts: 2805
Joined: Thu Feb 13, 2014 2:05 am

Re: Mono shock rear drive large seal leaking

Post by Rob » Sat Sep 16, 2017 2:08 pm

beemered wrote:
Sat Sep 16, 2017 7:41 am
I ordered a Lisle seal removal tool,anyone use one of these?
Looks pretty easy!

https://www.amazon.com/Lisle-58430-Shaf ... p_vse_rvc0
Rob V

Rob
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Joined: Thu Feb 13, 2014 2:05 am

Re: Mono shock rear drive large seal leaking

Post by Rob » Sat Sep 16, 2017 2:15 pm

Are you talking about #1 in the diagram?

http://www.realoem.com/bmw/enUS/showpar ... Id=33_1573

What year/model are we talking about?
Rob V

beemered
Posts: 16
Joined: Sun Aug 08, 2010 8:25 pm

Re: Mono shock rear drive large seal leaking

Post by beemered » Sat Sep 16, 2017 4:17 pm

Yes,that's the one.
1988 r100rs

Rob
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Joined: Thu Feb 13, 2014 2:05 am

Re: Mono shock rear drive large seal leaking

Post by Rob » Sun Sep 17, 2017 2:43 am

I have heard of sanding brake pads for disc brakes (sandpaper laid on glass), but I don't know if it works for brake shoes, or not. I'm betting NOT.
Rob V

Roy Gavin
Posts: 386
Joined: Tue Aug 03, 2010 11:21 pm
Location: Adelaide Australia

Re: Mono shock rear drive large seal leaking

Post by Roy Gavin » Sun Sep 17, 2017 5:21 am

Two problems with that seal, first is driving it in dead square, and second driving it in to the correct spot - you dont want it touching the crown wheel assembly.
Most folks seem to find the cover comes off easily , leaving the crown wheel and bearing in place, so if yours does it is easy to check, but the bearing must be refitted in the correct position with Locktite 242.
New Lucas TRW shoes will work better than the old shoes ever will and are well worth the cost.
Adelaide, Oz. 77 R75/7. 86 R80 G/S PD, 93 R100 GS, 70 BSA B44 VS ,BMW F650 Classic

Rob
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Joined: Thu Feb 13, 2014 2:05 am

Re: Mono shock rear drive large seal leaking

Post by Rob » Sun Sep 17, 2017 7:36 pm

Roy Gavin wrote:
Sun Sep 17, 2017 5:21 am
New Lucas TRW shoes will work better than the old shoes ever will and are well worth the cost.
That sounds like a good idea!
http://www.trwmoto.com/en/catalogue/result/
Rob V

beemered
Posts: 16
Joined: Sun Aug 08, 2010 8:25 pm

Re: Mono shock rear drive large seal leaking

Post by beemered » Mon Sep 18, 2017 9:21 am

Found no one in the States with those trw Lucas brake shoes (MCS941),found them on Ebay from Europe.Right now it looks like a place in France has best price,$40 with free ship.
As far as seal R & R,I will attempt repair without dissassembling cover.Manual states drive seal until it bottoms out,so no worry with depth.Seal was only $30 bucks so it won't be too big of a loss if it doesn't go well.Now to find a driver to set it square.
Will replace brake shoes after verifying leak is fixed.

Wobbly
Posts: 121
Joined: Mon Aug 07, 2017 8:48 pm

Re: Mono shock rear drive large seal leaking

Post by Wobbly » Wed Sep 20, 2017 10:15 am

Some thoughts...

• First thing to do is push-pull the wheel from the side. If you feel ANY play whatsoever (even 0.005"), then the big bearing is toast and that's why the seal is leaking. The big bearings are bad to self-destruct at about 85K miles on all single-sided bikes, which can lock up the rear wheel causing undue brown spots in your nickers. The technical term we professionals use for this is "bad boogie".

• Are you using synthetic oil ? Often times synthetics will leak when excellent, name brand mineral oils will not. Modern oils are so doped up with additives that no one on the planet can say where the dividing line between mineral and synthetic is anyway. I suspect you may be paying double simply to gain an oil leak ! Try some Valvoline 75/140 non-synthetic.

• Get the $42 official BMW seal from BMW Max and not some cheap thing off Amazon. They can be installed without final drive disassembly if you use P80 seal lubricant. The P80 will allow you time to "play" with the installation, and you can push it in with flat plates that contact the seal and FD housing, insuring it goes in square.

• Don't forget to also order the 2 new o-rings for the brake shoe cam shaft/spindle. They can leak just as much oil onto the brake shoes as the big oil seal.

• I've seen brake shoes soaked in solvents of all descriptions since the mid-1960's. Some chemicals so dangerous they're not even available any more ! None of them worked. I bought my last set of new EBC brake shoes on Ebay for $21. Get serious. Is your life really worth saving $21 ??

• I've found the EBC rear shoes to be more effective than the stock BMW parts, and at 1/3 the price.

• Don't ask me how I know all this ! :lol:

Owner 1988 single-sided R100 RS
After 20 years as a professional bike mechanic and 30 years as an engineer I know just enough to be dangerous !

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