Should have changed that final drive seal.

[Tony Smith]

I bought a final drive seal kit in the course of the restoration, but didn't use it as I waiting for a 32:10 final drive to arrive in the post. I figured that the low level of oil in the final drive unit would mean that it wouldn't leak during the roadworthy inspection - and I was right.
 
Foolishly I convinced myself that the seal had "taken up" and yesterday with the 200mile jaunt we had in mind for today in mind, I changed the final drive oil and filled to the recommended level.
 
I realized something was amiss when towards the top of the Gillies range the back end stepped out mid way through a right hand hairpin. i backed off a bit and inspected at Yungaburra  and the leak looked more impressive than it does now.
 
I think I'll break out that seal kit tomorrow and order another one when the 32:10 drive arrives.

[montmil]

Nothing like a wee bit of oil on the tire to really get your attention!

[Lucky_Lou]

A stich in time..... saves 9 as the saying goes, whats the rear shock unit it looks interesting.
Lou

[Tony Smith]

A stich in time..... saves 9 as the saying goes, whats the rear shock unit it looks interesting.
Lou

A piece of garbage is what that is....They were so cheap on eBay I could not help myself. To be honest, once I increased the pressure in the chamber to just under 100psi the damping just about matches the very firm spring rate needed to compensate for the less than 2.5" of travel available.

A complete waste of money! ($AU138 delivered IIRC)

[Tony Smith]

Nothing like a wee bit of oil on the tire to really get your attention!

And the near purchase of new seat cover to replace the one by backside tried to take a bite out of!

[arvo92]

That is a fair amount of oil. Even the tiniest dribble makes the brakes slide like a sledge. I changed my seal but somehow after 300 miles the new seal lost its effectiveness as well. A thin strip of rubber was hanging from the seals contact area - my guess is that the final drive unit has a small "tooth" on it and next time I really need to inspect that.

so take extra care because if one seal lost its properties, the next one could do the same. polish surfaces for that not to happen.

[montmil]

Most of our Airheads have some mileage on them. Wear patterns develop.

I've replaced a couple final drive oil seals and have always noted the wear pattern on the crown gear's shaft where the oil seal rides. It appears as a slightly different color. To properly check for any type of burr or inequity of the contact surface really requires removal of the crown gear. Your fingernail makes a fine inspection 'tool'. Any questionable area can be dressed using 400-800 grit wet sandpaper.

Protecting the sharp contact edge of the seal during installation is mandatory. The spline teeth can damage the seal without you knowing this -until it fails shortly afterwards. Also, prior to removing the old seal, note the depth it is sitting within the Cardan cover. There is a machined 'step' for the oil seal to rest on but I have seen seals seated slightly above this step in an effort to move the oil seal's fragile lip away from a questionable wear spot.

Protect your new oil seal during install by making your own Airhead "Special Tool" from a favorite 12-ounce beverage can. Cut the can to required length and thoroughly smooth the cut edges. Fine sandpaper works. Slide the tool over the splines, oil the seal and the can before sliding the Cardan cover into position.

Note: The photo shows a portion of the final drive splines only as a reference as to the fit of the can. Trim your beverage tool to completely cover the splines.