Newbie Shaft Seals question

[dbluefish]

I went through a bunch of posts on this issue and related on this and other forums(none as good as this, of course).

T^oday out for a 200 mile jaunt for lunch, at a stop, I noticed some slight weepage at the rear seal(?)area. Really not a leak but sort of misting. Took it to my dealer where an experience BMW mechanic took a look and said, yes there was a little seepage but that it was no big deal. In any case, he did not feel invasive surgery was needed(its a 2004 R 1150 RT with 15000 miles).

Any thoughts? Other than that and the replace QD issue(last week)the bike is a pleasure. Shifting is still a little notchy compared to my Harley (LOL) but I am just getting used to the bike.

Thanks and this seems to be a great forum.

paul

2004 R 1050 RT
2009 HD XR1200

SO's 2005 HD Deuce

[riceburner]

Unless you're utterly vain about keeping the bike clean - it's not an issue (imho)


it's only a problem if the oil is dripping onto the tarmac.

You won't lose enough oil from either the final drive or the gearbox to even notice it.
Both shaft seals are just above the oil level so you only get oil escaping when the bike is actually moving - and even then - it's a tiny, tiny amount.

[dbluefish]

Thanks.

Not a "clean" freak. I believe machines should be in as good a shape as possible and be used. I do however clean my bikes enough so i can spot things like this. Given the choice of riding a dirty bike and missing a ride, I ride the dirty bike!

paul

[MikeCam]

Agreed.

The Final Drive has a vent (spring loaded plunger at the top of the unit) that will emit a filmy oily residue that coats that area. The rear boot that covers the shaft where it enters the FD is known to collect droppings and eventually weep. That is what your description seems to indicate. As Rice states, not to worry. Rear seals and Main seals are known to fail. Most shop mechanics will tell you when it needs replaced. For DIY efforts, the rule I'd recommend is to not be bothered with it until you find a significant drop in fluid levels during inspections (FD and tranny), shiny metal slivers or flakes on drain plugs, or massive loss of fluid in a very short time. The last being the most catastrophic event is also the least likely. Other fluid seeps, weeps, and leaks that develop include the clutch slave cylinder. When that fails, fluid can contaminate the clutch disc. The oil drain plug - likely from poor torque or reused crush washers, but also from stripped threads. The oil filter - too loose or too tight. And, not so obviously, road grime can masquerade as a vehicle leak.

Generally, these Oilheads will show various less than perfect fluid retention areas around the engine, transmission, and final drive without the need for major service work. It is a matter of some debate to determine how much is too much. My experience is to watch and clean but until a leak generates regular drops on the shop floor (one per day or more) it is more a matter of cleaning than repair or replace.

[Boxer]

The Final Drive has a vent (spring loaded plunger at the top of the unit) that will emit a filmy oily residue that coats that area. The rear boot that covers the shaft where it enters the FD is known to collect droppings and eventually weep. That is what your description seems to indicate. As Rice states, not to worry. Rear seals and Main seals are known to fail. Most shop mechanics will tell you when it needs replaced. For DIY efforts, the rule I'd recommend is to not be bothered with it until you find a significant drop in fluid levels during inspections (FD and tranny), shiny metal slivers or flakes on drain plugs, or massive loss of fluid in a very short time. The last being the most catastrophic event is also the least likely. Other fluid seeps, weeps, and leaks that develop include the clutch slave cylinder. When that fails, fluid can contaminate the clutch disc. The oil drain plug - likely from poor torque or reused crush washers, but also from stripped threads. The oil filter - too loose or too tight. And, not so obviously, road grime can masquerade as a vehicle leak.

Generally, these Oilheads will show various less than perfect fluid retention areas around the engine, transmission, and final drive without the need for major service work. It is a matter of some debate to determine how much is too much. My experience is to watch and clean but until a leak generates regular drops on the shop floor (one per day or more) it is more a matter of cleaning than repair or replace.

BRAVO! This should be in a manual.

[jas]

Cleaning the boot area is fairly simple, cut the ties and move the boot to the front / back to remove the grime and then replace with new ties or a band. This will also provide a good opportunity to monitor the amout of fluid seeping at the boot.

[Sunbeemer]

I, alpng with others as you can see from these excellent responses, had a small weep from the front seal of the final drive that was just enough to collect road dirt under the boot on the underside of the final drive. I cleaned it up but it came back after a few days, so I changed the final drive oil and it has never returned. I think a small amount of dirt in the old (4000 miles) final drive lube got under the seal and allowed it to weep until the clean oil flushed it out.

I have been using Castrol Hypoy C gear oil 80W-90 in there changed every 6000 miles for 36,000 miles with no weepage.