Leaking Rear Final Drive - Lucas Hub Oil?

[ahaussmann123]

Hello all.

I have a leaking rear final drive on my 2001 California Jackal 1100. I sent it out to be rebuilt once it started really pissing oil, but even after being rebuilt it's still leaking sadly. I added the appropriate amount of AT205 reseal according to the label, and it seems to have slowed the leak but not stopped it. I'm currently riding around with the leak, and wiping the rear wheel before and after each ride. Minimal oil gets onto the rear tire. It doesn't feel dangerous yet, but it also doesn't feel exactly secure either.

Before taking it off for the hundredth time, I'm thinking of adding some Lucas hub oil or blue devil to try and get this leak to slow down. Any opinions? Opinions on ratio of regular gear oil to hub oil? Is it a silly idea?

If I have to take it apart again, I'll probably just buy a used unit. Sucks to be out $500 on a rebuild. Any suggestions I'm open to them.

[guzzisteve]

I have same going on but comes from trans to overfill rear drive. To answer the Q on hub oil by Lucas, there's no weight listed and when I added it it was like STP so I stopped at 500cc in trans and 250 in 85/140. It didn't transfer oil for 2yrs . The trans shifts like butter. I have around 90K mi on the drive train, all seals & new clutch & ujoint then. Just prolonging it being done again. No brown seals then, that's what needed.

The hub that the big seal in your rear drive rides on is replaceable. Is that what was changed?

Both seals ride on this hub--https://hmb-moto.de/Drive-hub-most-models-Drive-side

[Vagrant]

It's peanuts to change the big seal on the rear drive. Just go to the local bearing house and get a new one. Check for burs or rough edges then put it in flush.

[Wayne Orwig]

Any idea what they did to 'rebuild' it?

The big seal as pointed out is easy and cheap to replace.
The small inner seal is a pain to replace.
A bearing failure may be part of the issue also.

[aklawok]

 I had the same problem on my CalVin and did a post about it here.
https://wildguzzi.com/forum/index.php?topic=123143.0#msg1901953
The problem was not the seal but the paper gasket, there are 2 of them with a metal spacer between. Whomever the PO had do the work before glued them in, was a pita. to remove. When I replaced them i did not use anything. No leaks.

[kingoffleece]

Hamlin built a tool to replace the inner seal.  As mentioned, it's a bit difficult.  I needed him to do it correctly.

[ahaussmann123]

I have same going on but comes from trans to overfill rear drive. To answer the Q on hub oil by Lucas, there's no weight listed and when I added it it was like STP so I stopped at 500cc in trans and 250 in 85/140. It didn't transfer oil for 2yrs . The trans shifts like butter. I have around 90K mi on the drive train, all seals & new clutch & ujoint then. Just prolonging it being done again. No brown seals then, that's what needed.

The hub that the big seal in your rear drive rides on is replaceable. Is that what was changed?

Both seals ride on this hub--https://hmb-moto.de/Drive-hub-most-models-Drive-side

It comes from the transmission to overfill the rear drive??! How is that possible?? I have noticed that as I constantly replace the oil, drain and refill it, it seems to always be full even though it's been leaking. I have not checked my transmission oil levels in a while.

Good to know that the hub oil is not too thick to do damage. I might go 50/50 with the hub oil and see if it helps to plug up that leak along with the stop leak.

It was rebuilt by mark at moto Guzzi classics in Long Beach. He disassembled the whole unit, replaced a worn bearing, replaced all the seals, inner, outer, and paper gasket, and reassembled it in front of me. And I'm from New York! He hated doing that job haha.... he was very excited to paint it and be done :P 

I'm yet to inform him it's still leaking, I made an error when I reinstalled it so I feel boneheaded. (I sliced the o-ring connecting the driveshaft to the rear hub, called him for help, had to uninstall it again and put in a silicone 'the right stuff' gasket). He's been pretty friendly throughout the whole thing, and I lost my brother to a fatal accident last year so I've been just moving slow and making lots of mistakes.

Based on how I can see oil marks running along the face of the hub, I believe this time the leak is on the outer seal. If I got to try replacing that I will as everybody says it's doable. I'm just so sick of taking this hub on and off... I really hope the lucas hub oil does the trick, thickens things up enough to plug the seal while still providing lubrication to the gears.

[guzzisteve]

Simple, if you look at the pinion bearing casting you will see a 1/8 moon shape cutout on front bearing. Made to release air pressure into driveshaft area. If your rear trans seal is leaking oil can migrate down shaft right in. Even over filled mine don't leak. My seal rides on a newer hub. Dirt & crud can also make it leak. I would run a piece of plastic around & check. Costs nothing but time. Change seal, pops out easily & install w/a cup for an oil filter is about right size. You don't even have to pull it off swingarm.