First Shaft Drive, Seal Failing - Can I ride it 1,500 miles?

Mtbjay

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26K on a 2012, final drive weeping getting worse, now leaves a few drips after a ride. QUANDARY: Dealer can get me in next week, but needs 7-10 days for parts. My buds just invited me on a 5-day tour [Portland to NORCAL], leaving in 2 weeks. The dealer, in Beaverton, says Yamaha can rush the part for extra $$ but on their schedule (not FEDEX, UPS, etc.), and makes no promises on getting the bike back to me on time.

I don't want to miss the trip and am tempted to just clean it up, torque the assembly bolts and go. I'd bring fluid, check an refill as needed. The weep only leaves residue on the shaft side, not brake rotor side of the rim... so far. It's leaked a little for 3-5,000 miles, and was only this bad after the last ride of the season last fall: a one-day, 500 mile tour of Mt. Hood, Adams, St. Helens, and Rainier. I'm guessing the 90 minute, 80mph freeway run home had something to do with the extra fluid leaking... as it was slight before that day, and it's been slight for 3 short rides after that (the only riding I've done since the pics were taken last October).

Go or no go? Any of you push the luck on your final drive leaks? If I go, what are the odds that the seal might fail miserably and me needing a tow out of remote NORCAL? I'm willing to find out, unless y'all chime in and say it's too foolhardy. ::005::


I've never pulled a rear wheel. Looks like a 27mm wrench on the nut on the left, 19mm allen wrench on the axel, 8mm on the swing arm pinch-bolt and the wheels is off? There are 8-10 button-head bolts, holding the pumpkin assembly together I could tighten to improve my odds. They've never been checked, a far as I know (unless some kindhearted tire installer did it). Seems, if I'm going to risk it - I should check those bolts and see if I might get a 1/4 turn outta a few of them. It might be enough to slow/stop the leak.
 

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Nikolajsen

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If you make sure it don't run dry, I can't see a problem.
Unless of course it gets much worse, so it will "spray" on brake.
 

worncog

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Keep in mind that a lip seal with a minor leak CAN transition to a serious leak. I had a rear final drive seal on my C10 vomit the FD contents on the slab and then discovered at a rest area during a brief pee stop. Not what you want to see when you have 500 more miles to go that day.

Lip seals will leak if they have foreign material on or in the seal causing a pathway for the fluid to leak. If it IS a simple issue of dirt, you can simply clean the seal with a Seal Saver and carry on. The Seal Saver method usually works pretty good, and I have performed the cleaning several times on FD leaking seals. The before mentioned C10 had the seal cleaned with a zip-tie, refilled, and has been leak free for 30K+ miles.
 

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WJBertrand

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I wouldn't chance it if it were me. If it suddenly lets go you could end up with a pretty substantial repair bill, worse if it lubes the tire and you go down.
 

steve68steve

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I was where you are last July. I trailered 1000+ miles to CO to discover a leaking rear drive seal had caused a small puddle.


I brought fluid with me and checked it a few times while I was there. Silverbullet brought a spare seal with him, but I never installed it. I pounded the bike for two weeks out there with no issues - high mile days, high heat, sustained high speeds, high altitude, high number of drops and crashes. No drama, and another puddle on the trailer when I got home.


The seal can be replaced pretty easily without taking everything apart: carefully drill a small hole into the center of the seal's width, thread a screw into the hole (shallow!!) enough to grab the seal, use the screw as a handle to pull the seal out. You might need to repeat the process a few times around the perimeter of the seal to get a good, straight, pull. New seal presses in from the same side the old one comes out, just past flush worked for me. Make sure it's clean before putting the new seal in or you're back to square one.


Huge thanks to Silverbullet for that tip. It worked like a charm. Took longer to pull the wheel than it did to do the seal swap.
 

steve68steve

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Mtbjay said:
I've never pulled a rear wheel. Looks like a 27mm wrench on the nut on the left, 19mm allen wrench on the axel, 8mm on the swing arm pinch-bolt and the wheels is off? There are 8-10 button-head bolts, holding the pumpkin assembly together I could tighten to improve my odds. They've never been checked, a far as I know (unless some kindhearted tire installer did it). Seems, if I'm going to risk it - I should check those bolts and see if I might get a 1/4 turn outta a few of them. It might be enough to slow/stop the leak.

Back wheel: remove the wheel speed sensor (small allen), loosen the axle pinch bolt, remove the axle. Note that when the axle comes out, the brake caliper will be loose (hang it from the frame with a wire, string, bungy or something to protect the brake lines). It can be helpful to remove the brake caliper stay (the aluminum bar), but I don't think it's absolutely necessary.
There will be spacer and a washer on the axle, too - note their location for re-assembly.


With the wheel off, if you look from the brake side at the pumpkin, you'll be looking right at the seal. Mine was a brownish-orange color. You don't have to remove the pumpkin. If you're hell-bent on doing so, remove the four cap nuts that hold it to the swingarm casting - the drive shaft will come out with it. You could lube the splines and shaft, and check to make sure the weep hole is open in the casting. Don't fully tighten those 4 nuts upon re-assembly until the axle is back in and tight.


Taking the pumpkin apart is a much bigger job and not worth it, especially if all you have to do is press a seal in from outside the assembly.
 

EricV

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Take some spare fluid and just go. 75/90 Valvoline Synpower gear lube. I don't suppose you have actually checked the diff to see if the fluid is low or not? You might consider topping it off or doing a change before you go.

Do NOT just tighten bolts w/o knowing the torque spec! I can not emphasize this enough. You can snap off the bolt head or do damage in several ways by over tightening or tightening incorrectly. Some things have patterns, for example. This is what Service Manuals are for. All the more if you've never pulled the wheel yourself before. Perhaps you're a mechanic, but it doesn't sound like it so far. ;)
 

Mtbjay

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I looked inside the "diff" to and could still see fluid. I spun the wheel a little and some came out. So, it's not very low. I've changed it 2-3x in 26K. I thought I'd change it again, measure the drain, and see what I've lost to put it in perspective.

The wheel removal looks manageable to me. I've been a bicycle mechanic, and my arms and and hands are calibrated to not reef on bolts hard enough to sheer or strip them! Carbon fiber and aluminum are delicate things...
 

OldRider

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Like I said before, any dealer worth talking to can get you that seal in 2-3 days. I would be online first thing in the morning ordering the seal and have it put in by mid week. Why risk it blowing oil all over your rear tire???
 

Cycledude

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Sounds like u got pretty lousy dealer !
I’ve never had a final drive seal fail but I did have one leak many years ago, the only reason it leaked was because I had over filled it and when we got to Montana where there was no speed limit we rode most of the way across the state at over 100 mph, the extra heat and being a little over full must have started forcing the oil past the seal, anyway I drained the old oil and put in new oil without over filling it and it never leaked again.
 

markjenn

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I'd go. Yes, it's possible it could get dramatically worse, but unlikely. Much more likely is that it stays the same or gets slightly worse, but if you're monitoring it and keeping it topped off, you're fine to ride.

And I wouldn't get into a fire drill with any dealer at the last minute trying to get a rush job done. This could easily morph into having something go sideways which leaves you without any bike for the trip.

- Mark
 

Mtbjay

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OldRider said:
Like I said before, any dealer worth talking to can get you that seal in 2-3 days. I would be online first thing in the morning ordering the seal and have it put in by mid week. Why risk it blowing oil all over your rear tire???
Sounds like I outta order the seal in the morning! Is there only one seal? I recall seeing a variety of seals & o-rings in the exploded view. One helpful commenter gave a part number: seal #93102-70004-00. Is this the one you’re thinking of?
 

Mtbjay

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worncog said:
Keep in mind that a lip seal with a minor leak CAN transition to a serious leak. I had a rear final drive seal on my C10 vomit the FD contents on the slab and then discovered at a rest area during a brief pee stop. Not what you want to see when you have 500 more miles to go that day.

Lip seals will leak if they have foreign material on or in the seal causing a pathway for the fluid to leak. If it IS a simple issue of dirt, you can simply clean the seal with a Seal Saver and carry on. The Seal Saver method usually works pretty good, and I have performed the cleaning several times on FD leaking seals. The before mentioned C10 had the seal cleaned with a zip-tie, refilled, and has been leak free for 30K+ miles.
26k seems premature for a failure to me, especially considering I ride little off road and mostly fair weather. Also, I’ve never pressure washed it. It leaked some before, than all but stopped. I had this discussion (albeit with much less concern) and figured it normal to see occasional seepage.

I should still order a seal myself, clean, drain (measure fluid lost), refill & test.
 

Mtbjay

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markjenn said:
I'd go. Yes, it's possible it could get dramatically worse, but unlikely. Much more likely is that it stays the same or gets slightly worse, but if you're monitoring it and keeping it topped off, you're fine to ride.

And I wouldn't get into a fire drill with any dealer at the last minute trying to get a rush job done. This could easily morph into having something go sideways which leaves you without any bike for the trip.

- Mark
My sentiments exactly. From what I’ve gathered, Mark, I outta order a seal, clean, inspect, drain, measure, refill and test the bike. Install the new one as needed.
 

Mtbjay

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Cycledude said:
Sounds like u got pretty lousy dealer !
I’ve never had a final drive seal fail but I did have one leak many years ago, the only reason it leaked was because I had over filled it and when we got to Montana where there was no speed limit we rode most of the way across the state at over 100 mph, the extra heat and being a little over full must have started forcing the oil past the seal, anyway I drained the old oil and put in new oil without over filling it and it never leaked again.
I experienced the same, a year or two ago. It’s the same seal, only older and more leaky now.
 

Mtbjay

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steve68steve said:
Back wheel: remove the wheel speed sensor (small allen), loosen the axle pinch bolt, remove the axle. Note that when the axle comes out, the brake caliper will be loose (hang it from the frame with a wire, string, bungy or something to protect the brake lines). It can be helpful to remove the brake caliper stay (the aluminum bar), but I don't think it's absolutely necessary.
There will be spacer and a washer on the axle, too - note their location for re-assembly.


With the wheel off, if you look from the brake side at the pumpkin, you'll be looking right at the seal. Mine was a brownish-orange color. You don't have to remove the pumpkin. If you're hell-bent on doing so, remove the four cap nuts that hold it to the swingarm casting - the drive shaft will come out with it. You could lube the splines and shaft, and check to make sure the weep hole is open in the casting. Don't fully tighten those 4 nuts upon re-assembly until the axle is back in and tight.


Taking the pumpkin apart is a much bigger job and not worth it, especially if all you have to do is press a seal in from outside the assembly.
Great synopsis! Thanks! I’ll certainly try and acquire a seal, and some seal saver, and see if I can improve things. Thx for the explanation!
 

Don in Lodi

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Might be stating the obvious, but there are two seals than can leak. Make sure your oil flow isn't coming from the weap hole in the swing arm just in front of the pumpkin. ::008::
 

Mtbjay

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Don in Lodi said:
Might be stating the obvious, but there are two seals than can leak. Make sure your oil flow isn't coming from the weap hole in the swing arm just in front of the pumpkin. ::008::
I think the green-ish lube in the pics may have been from the weap hole, Don. But I'd only seen that happen last Fall, after the last big ride of the season. Several rides since (short) and I can't see any leaking from the hole. But, the bottom of the pumpkin is consistently covered in a thin film after a short ride.
 

Mtbjay

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I ordered 2 oil seals and an o-ring from Babbits. ETA 7-10 days. With any luck, I'll have that wheel pulled and the leak diagnosed by next weekend. Thanks for all the instruction, advice, and opinions mates!
 

Don in Lodi

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Mtbjay said:
I ordered 2 oil seals and an o-ring from Babbits. ETA 7-10 days. With any luck, I'll have that wheel pulled and the leak diagnosed by next weekend. Thanks for all the instruction, advice, and opinions mates!

The hub side seal can be done pretty easily. I think I've read that some specialty tools are needed to do the pinion seal. I've got a twenty year old Royal Star diff on a shelf because it was easier to buy a wrecker diff than to fix the pinion seal.
 
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