Author Topic: Rear drive leak (Read 2215 times)

czakky82 · « **on:** August 24, 2020, 07:22:46 PM »

I went for a ride with my wife a few days ago on my T3. We get home and my uni boot had oil dripping....
I left it alone (on centerstand) until today, went to grab some groceries and it seemed to get worse on my ride out there.

I drained the rear drive and found 220ml and she has never leaked on me before.

I just rebuilt the trans fresh seals, etc. I’ve got new Hagon shocks (12.75”).

I’m thinking this could be the old rear drive below the u-joint leak, but it got worse with just me riding it today.

As far as I can tell there is no way to seal the rear drive from the swing arm? I’m lost.... Any thoughts?

Looks like I’ll be pulling the swingarm again.

acogoff · « **Reply #1 on:** August 24, 2020, 07:33:44 PM »

Are you saying it is leaking at the rear of the transmission (gearbox)or back by the pinion bearing on the rear end (bevelbox)?

czakky82 · « **Reply #2 on:** August 24, 2020, 07:40:09 PM »

To me it seems it’s the bevel. The boot and uni joint are wet. The oil is black (moly) and the volume low (220ml).

fotoguzzi · « **Reply #3 on:** August 24, 2020, 08:14:47 PM »

So it's like the rear drive is pressurized so the lube is forced up the swing arm to the u joint? And your boot then leaks? Is a small amount of lube getting up there bad?
Could you have over filled the RD and it then pressurizes?

pehayes · « **Reply #4 on:** August 24, 2020, 11:00:20 PM »

Were you recently carrying some heavy cargo or a passenger or both? That could allow rear drive oil to migrate forward. What is the status of the shifting gearbox oil volume? Have you inspected the accordion boot for any cracks or tears? Once oil gets into the boot, there isn't really any way for it to get back out unless it is a lot and then it ends up overfilling the rear drive.

Patrick Hayes
Fremont CA

czakky82 · « **Reply #5 on:** August 25, 2020, 04:00:15 AM »

Thanks for responding guys.

@Foto, I do usually get the drive up to temp and crack open the fill plug. I am pretty confident I didn’t overfill. also when draining I had 220ml. Could it stay pressurized?

@Patrick, I certainly wouldn’t call my wife “Heavy cargo” but the leaking did start during/after a 70 mile two up ride. I’m about 200lbs she’s like 150. Like I said I have newer Hagon shocks and the leak LOOKED worse after my little 30 mile ride a few days later.
My thought was that if the rear drive was above the output seal that after a few days on the centerstand it would drain back into the rear drive....?

Frenchfrog · « **Reply #6 on:** August 25, 2020, 06:16:54 AM »

There seems to be a rash of these leaks at the moment !I'm just resealing mine ...made sure that the surface the lip runs on is good, hopefully good enough.If it still leaks then time to get the wallet out again

acogoff · « **Reply #7 on:** August 25, 2020, 08:26:08 AM »

You do realize that there is no seal keeping the oil going forward from the bevel box. Oil is held back there by gravity. Now if the shock's springs are not tightened for a significant haul, in theory, gravity would come into play to send oil up to the rubber boot. That said, Oil in the rubber boot is usually caused by the rear transmission seal leaking. If so, I would suspect that the sealing surface the the seal rides on, the speedometer drive, got damaged when the area was worked on recently. Great care must be observed to not to scratch this surface with a pliers or such while removing the drive from the shaft. Just a thought.

czakky82 · « **Reply #8 on:** August 25, 2020, 09:30:03 AM »

I was pretty confident that the speedo drive/sealing surface was pretty good and smooth. I did just replace this seal and it held perfectly for 1k miles. I even left the boot in clamped and inspected it frequently.
This sucks!

Thanks for the reply.

pcbiwer · « **Reply #9 on:** August 25, 2020, 09:48:59 AM »

On my 2007 Norge, my mechanic changed the rear tire and found the boot had cracked. That allowed a messy dusty goo to build up. Aside from removing it with solvent, he "patched" the boot with ruberized compound and it's made it another year. It's time to replace it soon, easiest when having a rear tire changed.

Groover · « **Reply #10 on:** August 25, 2020, 10:33:52 AM »

It would be great if the rear drive we're completely sealed having a seal on the shaft end. This happened to me a few years ago with my G5, same thing, rode about 60 miles 2-up on the highway going about 70 mph average. When I got to the destination, had rear drive oil all was over the place. When I returned, changed the large seal, new oil at the correct level, burped it, all those things, and was still leaking. Ended up being (likely) based on replies and assistance here, the inner seal on the rear drive, but since I didn't want to deal with that at that time and my skills for that are not there, I found a used low mileage rear complete drive on eBay for a decent price off an SP1000, rolled the dice, and it was good. (looked much newer than mine anyway). So in conclusion, if it's not the large seal, oil level, and the surfaces look good, then your inner seal probably cooked just like mine. My wife and I are not that heavy, well, average I'd say.

czakky82 · « **Reply #11 on:** August 25, 2020, 11:31:42 AM »

I’m fairly confident the seals are good on the drive. All oil was coming from the boot. Wheel, etc were dry.

Tom H · « **Reply #12 on:** August 25, 2020, 12:01:09 PM »

I'm having a hard time understanding how the oil in the rear drive can get to the U joint boot. It would have to get up to the carrier bearing (sealed bearing), then maybe pass through where the U joint goes through the bearing (should be a very tight fit), or have enough oil in there to be high enough to go along the drive shaft splines and in the U joint area. I'm not sure if there is even enough oil in the rear drive to fill the swing arm that high??

FWIW: My R75/5 has a sealed rear drive to the swing arm, You fill the swing arm with the correct amount of oil to lube the drive shat. To my amazement, there is no seal to keep the oil from going forward and into the U joint rubber boot.

Good luck!
Tom

blackcat · « **Reply #13 on:** August 25, 2020, 12:05:49 PM »

Quote from: czakky82 on August 25, 2020, 11:31:42 AM

I’m fairly confident the seals are good on the drive. All oil was coming from the boot. Wheel, etc were dry.

If you remove the tire and there is no oil coming from the large final drive seal or there isn't any evidence of oil on the spindle which points to the small inner seal then you're good to go. Sounds to me like the seal on the transmission. Why you are having this problem after a 1,000 miles is a mystery.

Wayne Orwig · « **Reply #14 on:** August 25, 2020, 12:55:48 PM »

Quote from: czakky82 on August 25, 2020, 11:31:42 AM

I’m fairly confident the seals are good on the drive. All oil was coming from the boot. Wheel, etc were dry.

I did not read in details, but.....
As mentioned, there is nothing to seal the lube in the rear drive at the swingarm tube. So, as you load the bike, more and more lube travels up the swingarm. If you do not adjust the suspension when you ride two up, the rear drive lube will fill the boot at the rear of the transmission. And that boot seldom seals perfectly, so you get a leak. Some swingarm pin bearings are not sealed, so it can leak there also.

czakky82 · « **Reply #15 on:** August 25, 2020, 03:21:16 PM »

I will have to go back in again I guess. It sounds more likely to be trans seal. I was just starting to fall back in love with this bike again.
There might be a very well fettled bike in the market this winter.

acogoff · « **Reply #16 on:** August 25, 2020, 04:23:08 PM »

Before you tear into it, I would load it up similar to what you had when the leak started and have someone have a look at the angle of the swingarm and bounce up and down some too. Would be a shame to take it apart when it is just a spring/shock setup thing. Maybe those shocks are actually shorter than advertised, just Maybe

czakky82 · « **Reply #17 on:** August 25, 2020, 04:51:34 PM »

I measured them and compared to old shocks. They are at least 1/4” longer unladen.

The other thing that keeps pointing me back to the rear drive is the oil color is black, which could be either dirt or the moly additive.

Tom H · « **Reply #18 on:** August 25, 2020, 05:22:30 PM »

I do not know if this would work. You could maybe try one of the colored gear oils in the trans OR the rear drive, for instance I think red line is red? Ride it a bit and see what color the boot has in it. Of course you would need to clean the boot really good so if it is the red, it would be obvious.

Good luck,
Tom

czakky82 · « **Reply #19 on:** August 27, 2020, 07:05:24 AM »

A quick update.
Inspecting the rubber boot shows they-joint completely dry. After replacing seals 1k miles or so ago I refilled the box with 720ml, I drained 710 out of the cold transmission. There was more metal swarf than I would’ve liked to see on the magnetic fill plug.

Wayne Orwig · « **Reply #20 on:** August 27, 2020, 08:49:12 AM »

Quote from: czakky82 on August 27, 2020, 07:05:24 AM

A quick update.
Inspecting the rubber boot shows they-joint completely dry. After replacing seals 1k miles or so ago I refilled the box with 720ml, I drained 710 out of the cold transmission. There was more metal swarf than I would’ve liked to see on the magnetic fill plug.

But you also mentioned that the rear drive was down to 220ml from the normal 250ml, and no visible leaks, correct?

czakky82 · « **Reply #21 on:** August 27, 2020, 09:07:12 AM »

Right Wayne.

Quick condensed recap:Freshly resealed transmission, dry rear drive at wheel, etc, fresher Hagon shocks.
1k miles after going for a ride with wife (350lbs payload) wet uni boot. Drained rear drive and trans found 220ml/250ml and 700ml/720ml respectively.

czakky82 · « **Reply #22 on:** August 28, 2020, 04:34:13 PM »

Output shaft pictured. Does the seal look deep enough? I have no clue where those little metal chips are from... sigh!

blackcat · « **Reply #23 on:** August 28, 2020, 04:49:52 PM »

Quote from: czakky82 on August 28, 2020, 04:34:13 PM

Output shaft pictured. Does the seal look deep enough? I have no clue where those little metal chips are from... sigh!

Mine before lubing it all up:

czakky82 · « **Reply #24 on:** August 28, 2020, 04:53:05 PM »

Looks pretty similar. Thanks

acogoff · « **Reply #25 on:** August 29, 2020, 07:14:00 PM »

I have a note on my workbench that states the distance from from a straight edge placed across the case boss to the edge of the metal part of the seal is
.630 inch. I imagine there could be a difference between cases, but that is what one trans seal measured. There is a machined boss under the seal, so I doubt you could get it in too deep if you just shoved it in farther, it should bottom out. The few chips I see in your picture are from the peening of the nut into a spline to safety it, I would say. And there should be no for and aft play of the shaft, If there is you have bigger problems than just a leak.

czakky82 · « **Reply #26 on:** August 29, 2020, 08:51:07 PM »

Thanks for the measurement Acogoff. I’m confident the seal is sitting deep enough, like you said there is a ridge there. I gave it a good few whacks for good measure. I thought for a minute about possibly forgetting a washer or something on the output shaft, but who knows.
Zero fore and aft play, she turns buttery smooth and it should since I spent like $45 on that output bearing.
It’s all back together now and I got in a little shakedown ride, everything is dry for now....

I keep going back to rear drive puking up through the tunnel as crazy as it sounds. Any of the oil I found from the leak seemed to be darker like it had the moly additive. Also that pic is just how I found the output seal, seems like there would have been more evidence of a leak if that was the culprit. Hard to believe but I hope it’s all that it was an overloaded bike. My wife and will start our diet tomorrow

News:

Author Topic: Rear drive leak (Read 2215 times)

czakky82

czakky82

czakky82

czakky82

czakky82

czakky82

czakky82

czakky82

czakky82

czakky82

czakky82

czakky82