Rear Sprocket Oil Leak

[mmoscari]

My 1956 OC4 is leaking oil from the rear Sprocket.  There is a spray patern on the outside of the sprocket.  The service manual describes removing the entire Final Drive to change the seal.  I assume, since oil is appearing on the outside of the sprocket, that the small outer seal is the bad one.  My question is can I replace the small outer seal from the outside without removing the entire Final drive or even the cover?

[mtncrawler]

The problem with that seal is getting the sleeve that it sits in out. I was replacing the bearings anyway so I pushed it out with the outer bearing and race. The seal sits up against a ridge in the sleeve and removes to the inside. Could you weld something to the sleeve and take a slide hammer to it?

[mmoscari]

Ive been reading alot about replacing bearings, boring and sleving etc....
I may have a bigger problem that I realize.  I hope my bearings are still good.  If after removing the track , I find the sprocket still tight with no wobble, I would asume that my bearings are good.  After a closer look at the assembly scematic, I see what you mean about the sleeve (Oil Seal Retainer).  If I remove the nut and trunnion, do you think a mini vice grip welded to a slap hammer could get the sleeve & seal out if I work it evenly around the circumferience?  How tight is the Oil Seal Retainer Sleeve pressed in?

[mtncrawler]

I remember it being pretty tight fit. Try the vice grip method and if that doesn't work try the weld something to it method. Surely Zimmerman's can supply a new oil seal retainer if it gets sacrificed durring removal. Of course if you are de-tracked and have the drive sprocket off it may make sense to freshen up everything anyway. That's the way this kinda stuff usually works out. You start to fix one little thing and end up rebuilding the whole deal.

[Eric Carlson]

When I did mine not too long ago, the retainer that the seal and bearing cup are in was about as tight a fit as a seal. That said, you could probably get it out with a small slide hammer/vice grip combo you mentioned.
I guess what I would wonder is, is the oil level in the final drive too high? If so, that's why the trunnion seal is leaking. A high oil level in the final drive is caused by oil leaking into the final drive from the transmission via a leaking pinion shaft seal. To replace the pinion shaft seal the final drive housing needs to be removed.
If the oil level in the final drive is where it should be then, after getting the track off I would check for play in the sprocket/ring gear assy. With mine the bearings were good but the track frame shaft (spindle) was loose in the housing (you read about that). If you have play, you have a bad bearing or a loose spindle. If you don't have play, you might get away with replacing the seal. I would be careful not to wreck the oil seal retainer because if you have to replace it, you'll have to "setup" or at least check the preload on the ring gear bearings.
Like mtncrawler mentioned sometimes it turns into more than you figured.

Eric

[mmoscari]

Eric,  You made some excelent points. Thanks for the info.  I did change the trans. oil before using it.  I may have overfilled it, causing this leak.  If I had a loose Track Frame Shaft like you did, would it also leak oil on the inside?  I'm going to check that tomorrow.  From what I read in the service manual the Preload is set before installing the Seal retainer, so I dont think a replacement will affect the pre-load adjustment.  I bought this machine just to do a project on my property, with the Idea that I will sell it in a year or two.  I do love using it, but my property is very small. I hope I don't have to re-build everything before the project is done.

[Eric Carlson]

My mistake! your right.
The shims between the trunnion and the outer bearing set the preload for the ring gear hub. I should pay better attention... sorry.
If you have a loose Track frame shaft it could leak oil on the inside as the oil would seep out by the innner track frame support. Mine leaked everywhere, it was filthy when I got it so it's hard to tell if it was leaking there but it was leaking on the outside.
I guess I wasn't so much worried about the leak as I was about the loose Track frame shaft wearing the ring and pinion gears out.
I didn't figure on rebuilding everything on mine but I'll be close when I get done. So far, I've done the lift and bucket cylinders, borrowed a spool valve, (waiting for the replacement) and the left final drive. If I push it really hard in the clay, the reverser pops out of gear so that's next on the fix list. It does work well though for a little machine.
I might be interested in your OC4 when your ready to sell. A dozer blade would be nice. Where are you located?

Eric