Check Out This Rear End...

[motoyoyo]

--Sorry, Carlos gotcha again, it's only a technical question--

I have about 33K miles on my '99S and just started seeing a seal leak at the rear pinion joint. So, it's time to go in and fix it. My question is what else should be checked, adjusted or replaced while in there?



I have also been experiencing some strange cyclic vibration at medium speeds that I have felt since I bought the bike about 8 months ago. I recently installed a short Paralever arm and the noise went away, but the leak developed at around the same time. It is possible that the short arm may have caused the seal to leak and has started lubricating the U-joints and quited them down. At any rate, I probably need to check the whole thing over thoroughly. The manual shows a whole bunch of special jigs and service tools and adjustments. Has anyone had their BMW dealer do a full service on their Paralever? Now for the scary part...What would, or could something like that run if BMW performed the service?

[markjenn]

This is exactly the same leak I had at 20K with a stock paralever. I doubt it is the paralever that caused it. It seemed heat related - in cool weather, it could seal, but it would weep in hot weather. Fixed under warranty at unknown cost - no problems since. I'd fix the seal, but if there are no other symptoms, I wouldn't start ripping into it. You do probably want to see how the "play" is doing up at the swingarm pivot.

My take is that the cyclic droning/vibration is related to phasing of the drive shaft and u-joints, so changing paralevers will cause changes. It comes/goes on mine, although it is never bad enough to be anything other than a minor annoyance.

I'm about to go with a shorter paralever, but I don't think I want to go all thl way to GS length, both to reduce deviations from stock and to allow keeping the centerstand.

I sent mail to Brian trying to get in on the last custom paralever order, but got no answer. Anybody know what is going on there? Anybody got a good email address? I don't care much about looks - I just want something about 3/8" shorter and not spend a fortune.

- Mark

[roger albert]

Hi,

I think Mark has it nailed. It's all pretty easy stuff to do and you don't really need any of those jigs. They just make it easier. I'd take care of the seal, but make sure the seal didn't go due to a wonky bearing allowing shaft runout. i.e. is the leaking seal cause or effect? Ditto the advice on looking at pivot bearings. I'd check rear carrier bearing play too. None of it is as hard as he manual says. Good 1/2 drive allen sockets (can't remember if 8 or 10mm) will help. Not much needed specialized.

hth
roger

[Dave Hopkins]

Mark
I went with the high dollar adjustable link, stared at it, rode it, adjusted it to the "GS" length and doubt that I will ever touch it again? Good conversation piece.

[repoe3]

you might have missed out, but 10 of us got the arms. perhaps he replied only to the 10 that answered him. we hope to see the arms next week. perhaps you can get another run done. i already have the short arm as it is going on an SBX, so i and firebolter went with the shortest arm he makes, beleive it is equivalent to the short arm on the bike now.

let us know how the repair on the rear drive goes, as i am racking up the miles and trying to do all my services, i do intend to watch things closely as i still have two years and another 24k miles of warranty.

repoe3

[pdonnell]

Wheres the oil coming from? Gearbox or Diff? I had a leak like that but the rubber boot hadn't been off in years (4) and when I took it off about 3 teaspoons of oil seaped out. after talking to the dealer I put some dye in the gearbox oil and checked out levels of both diff and gearbox and both were fine. After 6 months I am still waiting for an accumulation of oil. Dealer indicated many possibilities for leakage but it appeared to be a good idea to start with finding out where its coming from.
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More importantly though. I don't consider 3 teaspoons of oil in 4 years to be very much. I mean, enough to really jump on replacing seals ASAP.
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.
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Maybe this is where all the engine oil goes to since at 32000 miles I still have to add engine oil occassionally.

[roger albert]

Hi Repoe,

do you have Brian's latest contact info. I'd bought an arm from him previously and wrote twice to get in on this build, but never heard back.

thanks
roger

[markjenn]

Anybody know what the standard "GS" arm goes for from BMW?

I assume if I want to keep a centerstand and the GS arm, I'd need to weld some spacers on the bottom of the stand?

Thanks,

- Mark

[repoe3]

mark

dont think the bmw piece is that expensive, and you are correct, weld some spacers to the center stand and you are good to go. tell you what, i will sell you mine off the boxer cup prep when the other shows up. will make you a good deal.

repoe3

[Dave Hopkins]

Mark, $70 to $90 range. If the rest of the bike is standard your Centerstand will be OK, easier to get the bike up onto and tire as I recal just off the ground, if you have the sport shcok or the 5.5 wheel/180 tire then you need to lengthen the C stand a bit.

[Rapid Dog]

I've heard $60 to $80 depending on the source for the OEM GS arm. There is a thread here somewhere...

[CarlosT]

Looks like a bad seal. I had mine go bad at about 12K miles. At 33K miles I would look at other things to rule out a bad bearing.

[motoyoyo]

Thanks for the replies all. Since everything still feels good back there I think I'll start off with what pd suggested and check oil levels first. I'll pull the boot back and get most of the oil out, then check and top off the differential and gearbox fluids. A few more rides will probably reveal the source, if at all. If I don't see anything after a few rides maybe I can put off replacing the seal for a while. Otherwise, I'll take Mark and Rogers advise and just go in and replace what's necessary and not get too carried away.

BTW, I picked up a stock BMW sport (GS) arm from Bobby at Atlanta BMW for $79. I think shannonnunley was the one that found one at, I believe it was Hammersley BMW, for $69. If you don't mind the stock look then $69-$89 is certainly worth the money for one. I'm with Dave on the length issue. I went from totally stock to a sport torque arm and Ohlins shocks and I wouldn't want to lower the back end a bit now, after riding it this way.

[markjenn]

repoe3, yes, drop me a line when you get your new arm and let's make a deal. Is the prep arm the same as the GS? The email address in my profile is good.

Scott, sorry to hijack your thread. Good luck with your repair and let us know what you find.

- Mark

[motoyoyo]

NP Mark, yes the prep is the same as the GS.

[moose]

My rear boot leaked, although not that badly. My dealer replaced the zip ties with stainless hose clamps designed for the job at no cost, saying those plastic clamps were a problem. They should replace the crummy clamps even if you are out of warranty.

[DavidSoine]

GS arm was 64.40 mailorder from Chicago BMW. They give a pretty good discount - I wind up buying a lot of parts thru them for the bike & car (have the parts numbers ready for car parts!)

I've yet to install the GS arm, tho...maybe this week...

-ds

[brad black]

we replace a few seals, but not a huge number. you need special tools to get the seal carrier out to do it the official way, and it's well worth getting the seal runner out to check the surface - which can be a real pain in the arse. not sure how i'd do it without the special tools.

the cyclic noise/vibration - i have it on very good authority - is rear drive backlash related. from people who have fixed the problem more than once. we've never had to do one. adjust the shim under the small, outer rh (as fitted to the bike) bearing.

[tominator]

How about this rear end?



I'm Leaking!

[fiery]

Nice suspension!



fiery