Pulling trans and Variators

[teledawg]

Re: thrust bearing

Lyndon, here is the narrative you are referring to in the link you provided above:

Re:Thrust bearings
Most of the snow track OEM bearings and seals are SKF part numbers and are actual SKF parts. The number series has been changed in some cases, but can still be cross referenced by a baering supplier. The Thrust bearing that pushes the pulley halves closed is readily available and I use a Check republic copy from ZKL, it's a 51110A. This bearing appears to the naked eye to be the same on both sides, but actually one side is slightly smaller than the other. One side fits snugly on the Chive, over a collar. The other side pops in the cap and the race goes in between. The 'cap' is ST14A, the Bearing Bracket and the 2 parallel arms press against it. The top one has a zerk fitting, the lower one, on the other side of the variator has a hose barb, short hose and the Grease Zerk fitting that bolts on a bracket on the side of the engine compartment. The lower one rarely if ever goes bad, where as the upper one gets wet and will likely have to be replaced so you only have to buy one when you do a rebuild.


Here is a picture of mine...the lower bearing race looks to be part of the sheave /chive casting. I cleaned and scraped looking for separation between the two but couldn't find it. Also, when I put a wrench on the race the outer edge EASILY chipped off revealing raw metal which looked cast.

It looks like the bottom race is missing. No wonder the thrust bearing failed! Cast iron is not a very good bearing race...

 

[Snowtrac Nome]

i was thinking the same thing i found the same problem with mine when i got it running

 

[300 H and H]

This kind of damage can be repaired with a sleave made on a lathe I bet. That is the way I would do it, were it me. You have a good one on the other side to measure from. Need a big enough lathe to swing the sheeve in the headstock. Peel enough off to clean it up, and then turn a sleeve to get it back to the original dimentions. Drill and pin it 4 places to insure it turns with the sheeve. The bearing race should be a tight fit on the sheeve hub above this new piece, if it is not damaged, as it very well could be. This area could be sleaved back to size as well with a heat shrink fit sleave. I have fixed several shafts in gear boxes this way with good results. I would think it would work here as well. Just need a lathe and an operator.....

Best of luck with the repairs, Kirk

 

[AKdadio]

Mystery has been solved:

The last person to re-assemble the drivers-side variator put BOTH of the races on the same side, one on top of the other into the bearing holder (st14a). They didn't put ANY race on the top of the sheave/chive. Over time the bearings wore down into the casting to create a "race".

1st and 2nd pics (both races on one side). Lyndon points out that one race has a slightly larger ID, this one is supposed to go in the holder, the one with the smaller ID goes on the sheave. In this case, they put the large ID in first then the small ID in on top of that which made it look like there was a place for an O-ring (one of my original observations). The races were pressed in place and fairly tight fit, they did NOT have a p/n on them.

3rd and 4th pic (the back-woods fix). There seemed to be enough casting left on the top of the sheave to support the race, but I decided to fill in the slot the balls had worn down with epoxy-steel. This is a simple approach which I hope will serve the purpose. If not, I will address later.

5th and 6th pic (how it is supposed to be)

 

[AKdadio]

Lyndon, here is another photo of the seal that is in ST14a, this is of the passenger-side holder which was STILL INTACT. The 1976 Parts Manual (pg 17 item 61) shows a p/n CB 70 85 8 and calls it a "sealing". What is in mine is a BA 70 85 8. The ID of this lip-seal fits snugly around the part of sheave/chive that the race rests on. It should help minimize grease spillage so I will try to find a replacement.

 

[AKdadio]

Lip Seal in Thrust Bearing Holder

It looks like I will be on the hunt for a new one of these: an R21 style seal.

 

[AKdadio]

Thrust bearing.

Seal is available from Alaska Bearing so I will be back in business soon, just need to decide whether I do anything about the groove worn into the top of the bearing holder. Kirk, your suggestion on welding/heating is appropriate but I may just leave it be for now. There is a LOT of material left to the bearing holder and I doubt the change in "height" will make a difference in steering adjustment.

Anyone think reinstalling as-is is a bad idea? here is photo again.

ps, thanks to Mike for letting me take over his thread, Fred...kudos to you for guessing that the race was left off and thanks to Lyndon for always participating with advice and experience. Don, won't need your spare bearing either but thanks for offering.

 

[Snowtrac Nome]

you won't have to worry about the epoxy i have fixed manny race seats with epoxy and it will work just fine

 

[AKdadio]

When tearing down a variator it is important to take out and free up every one of the stepped washers and all the associated shafts. I recommend a plumbers tubing brush, cheap and redily available, for the insides of all the 1/2 holes, and steel wool or Scotchbrite for the shafts. There are I believe 10 of the special stepped washers.
.

Here is the subject washer Lyndon refers to. I am missing one. I searched for bronze flanged bushings as a suitable replacement with no luck due to the unusual dimensions. It seems a shame to have a machine shop make 1 just for me.

Anyone have an extra?

Know where to get a:

15mm ID x 24mm OD x 11mm (length thru bore)
The flange size is not critical but: 30mm flange od x 4.5mm flg thickness.

 

[Snowtrac Nome]

where did that washer come from i can likely accomodate you on one i have a spare varriator i robbed a shaft out of till i can get to spare parts this summer

 

[AKdadio]

where did that washer come from i can likely accomodate you on one i have a spare varriator i robbed a shaft out of till i can get to spare parts this summer

Item 33 is the bushing, there are 8 of them in various places.

 

[Snowtrac Nome]

i pm'd you and do have one