rear axle seals on jinma

Soundguy · May 1, 2004

I've been a jinma 'watcher' for a few years now... I've driven a few, and seen and 'smelled'alot more. I finally notices something today that I hadn't noticed before.

On the outter ends of the axle trumpets.. there is agrease fitting near the axle seal.

Now on many antique tractors, even when there was an oil bath for the axle and bearing, there was an inner, and outter felt seal behind the axle seal.. and this is where the grease from a grease fitting was pumped into... ( think jd letter series.. a/b, etc. )

Other antique tractors.. and most modern ones I've seen.. simply use the seal, and have complete splash oil lube/bath for the rear axles and bearings.. and no outter grease fitting.

The only other application i have seen anything similar to this was on some old farmalls that had a grease fititng on the pto bearing carrier. I had always wondered about that as the pto was tranny countershaft run.. and thus was in the rear oil bath... I wondered why the rear seal/ bearing needed grease while it ran in an oil bath. Upon actually reading the parts manual it became plainly obvious. the pto sat above the oil level inthe tranny/diffy sump, and the oil slinger was axle powered... in other words.. if the tractor was stationary, and running say.. a belt pulley... the pto wasn't getting splash lubed.. like it would when driving, and hte axle oil slinger splash lubes the whole sump.. etc.

Just noticed that and thought it was odd... Figured their technology was old.. but not 50-60 years old /forums/images/graemlins/tongue.gif

Still.. it works good for my 54 year old 'B' .. guess it will work for a brand new jinma..

Soundguy

WildBill99 · May 6, 2004

That is interesting. I had noticed those too, I also thought it was odd, but I hadnt really thought about why they were there. I put a couple of shots of grease in there but I didnt want to load it up and blow a seal or something. I guess thats a good thing I didnt.

Soundguy · May 6, 2004

The only other thing I can think of is that the bearings are in front of the oil seal, and thuss need grease lube.. hard to say without seeing a axle parts diagram.

Soundguy

JohnS · May 6, 2004

Here you go: Rear Axle

Soundguy · May 7, 2004

Thanks for the diagram.

Yep.. it deffinately looks like seal 146 sits very close to the front of the axle, in the area of 123 on the axle, and right up against bearing 154, and then bearing 154 is setting behind what looks like a 2 piece seal 155 or two seal 155's, and then the outter seal/bearing retainer 156. Looking at the other side assembled.. the grease fitting is at a place where it could lube the bearing, and seal lips 154 and 155.

So my guess may be correct. In a way.. that is a pretty darn leakproof axle.. 3 seals and a grease packed bearing before oil can escape fromt he axle trumpet to the outside world.

Kind of the best of both worlds technology wise. And greased outter bearings work fine in my experience. As our 50 year old ford N's get bad leaky axle seals on the early models that only had 1 seal ( later models had 2 seals ).. and there is an aftermarket sureseal that can be installed that keeps oil away fromthe axle bearing.. meaning you have to pack it with grease before putting the hub back on... probably thousands of these conversions running around today working perfectly..

Soundguy

JohnS · May 7, 2004

No problem. One discussion that comes up it the Jinma circles, is just how much grease to pump into those axles. It seems to take an endless amount. After what should be reasonable, people stop, afraid to blow a seal.

Soundguy · May 7, 2004

Yep.. I see your point.. too much grease will force that inner seal out. I would guess that the bearing size is what is going to determine grease amount.. I'm guessing 'handfull', it looks like a straight roller bearing.. not tapered.

On the old jb-b.. there was no outter seal per say.. just a felt seal under the retainer.. so when you ovegreased it.. som grease pushed outa the felt seal doing no damage.. course.. it didn't have the leak proof benefits of 3 seals either!

thanks for the discussion

Soundguy