Rear bevel drive seal replacement (small block)

[sib]

No cheap Chinese junk.

Well, they did build the Great Wall, and it has lasted a while.  But, seriously, Chinese-made no longer equates with cheap or shoddy.  I'm old enough to remember when the same attitude was applied to items made in Japan, before they started selling Nikon, Toyota, and Sony products here and teaching us a few things about high-quality manufactured goods.

[Cassidy]

SED,
Great discussion, too bad I discovered it after I performed the task. I am a new owner of a 78 V-50 and on the first 26 mile (rainy day) ride I came home with oil over the rear tire. Diving in, to replace the (3) paper gaskets which I thought were the culprits, I noticed the bolts on the ring gear seemed loose... no, one was sheered. The rest fell into place, if you're in that deep, might as well go for all the seals. You couldn't have described it better. Putting it all back together, I then found and read your piece and realized I missed the last seal and went back for a second operation. Still trying to get the (perhaps original) seal out, but I am there. (maybe not my oven yet, a girl's gotta cook).  One note I may add, after putting it back together the first time with new bolts and Loctite on the bevel gear. (it works). Breaking the Loctite is a cinch using Methyl alcohol (in my case, dry gas) A few drops and a mere minute does an amazing job.  Thanks for the pics too, they made me feel sane. Now if only the snow would leave.

[kevdog3019]

Very nice; thanks for this.

[Muzz]

Thanks for that, SED. Attaboy. ;-T We're beginning to get some small block stuff documented here. I wish someone would do the transmission..

That has been done.

Nick Webb documented this on "This Old Tractor". NolaGuzzi, Nick and myself all had gearbox problems. Theirs were to do with the pre-select fork, mine was somewhat more complex and required a lot more parts to fix. ::)

Written I might add with a humorous vein running through it!

[Muzz]

I must say, great write up SED. ;-T

[Simmoto]

This is a fantastic thread, I'm following the steps to replace the big seal on my Lario bevel drive. thanks! 

Can anyone tell me how to replace the small, outer seal and the pinion seal while I'm in here? Promise to post up photos when I'm done!

Thanks 

[Chuck in Indiana]

This is a fantastic thread, I'm following the steps to replace the big seal on my Lario bevel drive. thanks! 

Can anyone tell me how to replace the small, outer seal and the pinion seal while I'm in here? Promise to post up photos when I'm done!

Thanks 

While you're there..  There is a mod to drill a hole so the pinion bearings get lubed. I posted something on that several years ago.. I'll see if I can find it.

It's in the Monza annual inspection thread:
http://wildguzzi.com/forum/index.php?topic=89034.60

[Simmoto]

Thanks Chuck, yeah I'd read about that - it's beyond my ability right now so I'll leave it. Still trying to figure out the outer small and pivot seal removal....

[Chuck in Indiana]

I've not done that one, so can't say. Shirley  it can be done by ordinary mortals..

[SED]

Thanks Chuck, yeah I'd read about that - it's beyond my ability right now so I'll leave it. Still trying to figure out the outer small and pivot seal removal....

Glad you are finding this thread useful - great! 

Don't be afraid to try drilling the oil passage.  It's easy to do now if you got the rear drive this far apart.  It's easy to start in the right place and the hole just has to end up close to the forward bearing.  Drill the hole, and chamfer & cut the burrs off with an exacto knife.

Start here:




Aim for here:

[Simmoto]

So here's how I did the small seal. It's under a bearing that's pressed into the casing and you have to remove the bearing and the washer beneath to remove the seal.

The only way I could remove it was with a blind bearing extractor. Still a bit tricky as there's not much room between the bearing washer and the seal to get the lip of the extractor. In this case the seal was well and truly knackered.

Measure how much of the bearing is proud of the casting so you know how far to put it back





Insert the correct sized puller beneath the washer that sits beneath the bearing





Extract the bearing,





Clean the housing. I found the old seal hard to extract so used the puller on that too.  Then push in the new seal - I used the face of the bearing extractor to tap it in. Then insert the washer and tap the bearing home so it's the same distance proud as it was before.





Hope it's useful
Cheers

[Chuck in Indiana]

Yessir.. I *assumed* it would be similar. Thanks for that.. It'll be good when someone finds this in a search.

[SED]

Yes - a great help.  It will give me courage when I have to do it.  Thanks!

[Diploman]

This is an excellent, very helpful thread which will facilitate an operation that sooner or later will face most smallblock owners.  It's good that the photo doc is now complemented by a further, more recent bit on extracting the outer roller bearing and replacing the smaller outer seal.  All the possible upgrade operations are now covered:  large inner seal; large inner ball bearing; outer roller bearing; outer small seal; lubrication passage for pinion bearings.

When I replaced the large inner seal on my 1980 V50II in 2016, the outer roller bearing did not come out of its housing with the hollow shaft, as shown in the photo tutorial here.  I elected not to replace the small seal or the outer bearing at that point, since both were operating properly (and have continued to do so to date).  I extracted the hollow shaft from the large inner ball bearing with a shop press, but SED's whacking-on-wood method is more resourceful and requires less equipment.  Good show!

I can't remember where, but I read somewhere that a European smallblock owner who often rode his bike in the rain was frustrated at the need to repeatedly replace the large outer seal, due to corrosion which inevitably formed on the exposed steel edge of the hollow shaft outside of the seal, then degrading the seal. This, of course, is particularly a problem when the hollow shaft is often exposed to rain. 

The solution: a very thin stainless sleeve placed over the entire surface of the hollow shaft contacted by the seal.  This sleeve covers the edge which corrodes if exposed, preventing the surface from any further corrosion which will damage the seal.  Timken and SKF offer such sleeves, and probably other bearing manufacturers as well. The next time I replace the large seal I plan to install such a sleeve, which offers the promise of much longer life for the large seal, and far less hassle for the smallblock owner.

https://www.timken.com/products/timken-mechanical-power-transmission-products/seals/redi-sleeves/

http://www.skf.com/us/knowledge-centre/media-library/index.html#tcm:12-128020

[Diploman]

A couple of notes:

- In his Guzziology discussion of the pinion-lube fix, Dave Richardson advises reversing the metal shim between the backplate gaskets so that it forms a sort of dam that makes lube pool above the upper side of the pinion bearing housing, thus allowing the lube to be driven down the (newly created) passage into the space between the pinion bearings.  Makes sense.

- Dave also discusses the inadequacy of the OE lock plates to secure the ring gear bolts. His solution, which he says works reliably, is simply to tighten the bolts -using red Locktite - directly down onto the ring gear, with no washers or other devices.  In recent years it seems to have become customary to use Schnoor washers for this purpose.  I followed the Guzziology recommendation when replacing my V50II big seal and have had no issues in over 8K miles.

-Recently a forum member started a thread on a new type of lock washer, the Nord-Lock. This, to me, sounds like an even better bolt-securing device than the Schnoor.  When/if I need to replace the big seal again, I intend to use the Nord-Locks.  (I already have a set of them on hand.)

https://www.indconsupply.com/nord-lock-3-4-locking-washer-carbon-steel-2150.php?gclid=EAIaIQobChMIw-jC36f42AIVXDkMCh1_dQBJEAEYAiAAEgKeYPD_BwE#yt_tab_products1

[SED]

Great addition Diploman - thanks!

[Simmoto]

Yeah some really good contributions from Diploman! I agree completely with the corrosion on the  hollow shaft causing the big, inner seal to leak. SED says in his thread he had this issue and so did I - we both used 400 grit to remove the rust but a stainless band would be a better solution I would think.

My rear disc is now hot after a ride - I can touch it but I wouldn't hold it for long! I am pretty sure its heat conducted from the bevel drive as there's no binding of the rear pads. The housing is cooler on the outside and around the pinion so I don't suspect the cogs. So it's either paranoia on my part (after all its probably always been hot and I didn't notice) or something to do with the big inner ball race bearing - that I didn't touch. of course I never touched the rear disc before the bevel rebuild so no baseline.....Can someone confirm it's paranoia - 

[Chuck in Indiana]

Weird. I went back to some small block threads where I documented reversing the metal shim, Nord Lock washers, etc. and the pictures are *gone.* The last time I looked, Photoblockit had released their hold on them, and they showed up. Even Flickr pix are missing? What up with that? <Grumbling and shufflin off>

[Simmoto]

Yup that's odd Chuck....no images?

I've added 10ml of moly, and will see if that reduces the friction/heat generated. I just added the end of an old tube when I filled it up so very little in - forgot...