Firstly, apologies for the length of this post. As the name of the thread suggests, I’m looking for some advice on what might be going on with the final drive on my ’08 R1200GS, which has only 30k miles on it.

This started with what, to me, looked like evidence of a very slow leak from the outer (right hand) final drive seal. The evidence was the usual tell-tale black gunk that collects when oil and dirt mix and it was on the underside of the final drive housing, from the seal down. I did some online searching and found indication that failure of this seal can be caused by not riding the bike for some time. This seems a plausible explanation since the bike was garaged for about 4 – 5 months late last year. It was only in December that I managed to put some miles on it and then noticed the slight leak.

Anyway, I took it in to the local dealer who, without really looking at it, confirmed that they would replace the outer seal only. They did this last weekend and that’s when the real trouble started. I went to collect the bike and they hadn’t quite finished up so had to wait. While waiting I saw a technician take the bike out, I assume for a test ride which lasted no more that 5 minutes. They said the bike was OK and I paid up ($120 all in) and headed home – which is only ¾ mile away. On arrival at home, I checked the final drive and there was oil dripping from the bottom of the housing (not the new seal) and seemed to be coming from between the brake disc and the housing itself. The oil had clearly sprayed on both the tire and the rim. See the pictures (sorry but couldn't get the the right way up!).


I immediately returned the bike to the dealer who, because of the late hour said they would look into it the next week. Now, after having had the bike for a week they are telling me that the “large O-ring” has failed and needs replacing. I am assuming that the O-ring is the one in the following picture (courtesy gtrider_texas from a different thread).

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So my questions are:
  1. On the first seal replacement is there any need to pull the final drive apart and disturb the O-ring?
  2. If there was no reason to disturb this O-ring, what is the likelihood of this failing at the same time as the other seal? Could it have also “dried out” due to lack of riding? This doesn’t seem likely to me.
  3. If the final drive had been over-filled with oil after the first seal replacement, could that have blown out the O-ring?
  4. How difficult is it to over-fill the final drive?
  5. Has anyone experienced a failure of this O-ring while riding? It seems to me that this would be very dangerous given the volume and rate that the oil was coming out and ending up all over the side of the tire. Not to mention the likelihood of severe damage to the final drive as it ran dry.

Thanks in advance for any help.