The Stovebolt Site Forums The Shop Area Driveline HO52 Pinion Seal

I am replacing the pinion seal on my 71, 3/4 Ton pumpkin on my 51, 1 Ton. I removed the yoke and bearing retainer today. The seal which is not original has been installed deep in the opening. The top is about 1/4" down from the edge. I also see that the large lip surface is facing outward so I don't know how it was driven in. When I get the new seal, can it be installed so that it just clears the opening? If not, how would I drive it in?

OK, so I had a closer look and indeed the metal lip faces the inside where the force would be applied to drive it in. So now my question is how far in do I have to drive it and what should I use to drive it in.

Hy truckernix, it is common practice to adjust the position of a seal in a bore (if that is possible), or buy a thinner seal in order to avoid a worn area on a shaft or in this case the pinion yoke. You could use the yoke with the seal in place on it to push the seal into place, once the pinion shaft threads are exposed you could thread the nut on to push the seal into place, you will have to push the seal slightly farther into the bore that the yoke will push it to come up with a running clearance, you could use a large socket or an appropriate size of tubing or pipe to finish the seal installation, hope that helps.

I'm a little foggy about what you're asking Fred. But I'll give
it a shot. There is a 3653617 bearing retainer felt that goes
into the space between the seal and the bottom of the bore. I'm
assume that it acts as a first-line of defense against gavel,
sand or other road grit getting back into the lip seal, which
should be flush with the back of the retainer if I remember
correctly. It's been 5 or6 years since I redid my HO52 in
the '50, 3600.

Denny G

Denny, my seal does not have any felt beneath it and it is basically driven to the bottom of the bore. I didn't know that they still used the felt. I thought that was part of the old style packing. In any case I was asking whether it was necessary to drive it to the bottom of the bore.

I'm almost positive the felt packing was used in addition to the
lip seal all the way up thru the 60's. If yours didn't have it
I would check the clearance from the back of the retainer to
the seal and make sure it's not going to interfere with drawing
the bearing up tight.
It's entirely possible that they may have done away
with the felt by the 70's
DG

No felt in any of the ones I have taken apart. I've taken apart 4 HO 52's in the last few weeks. Must have been discarded.

Dug out my later parts book and I've got 55-65 2nd
3/4, 1 TON. So if Fred's is a '70 not to worry, at
least according to the parts book.
Earlier parts book up to 1957, shows it used 46-57 COMM, UTIL.
I've had three of them apart which did have them. Taint gonna
go out in the cold barn to tear one apart for a show and tell
today.
Had pictures of two of them disassembled on Webshots but we all
know what happened to Webshots also my cornfuser with all of my
archived pictures crashed last year.

DG

If I want to drive it to the bottom of the bore, I just have to figure out how to do that. I will look around to see if I have a bearing race that would do as a driver. Re the bearing retainer: I would think the thickness of the gasket becomes quite critical here. For instance, if I made a gasket and it was too thick, the bearing might be loose.

Denny..the pinion seals appear to have been replaced on the ones I took apart, they must have discarded the felt. I just put my retainer on with RV ( as advised by a few mechanics), I can't see how gasket thickness would be very critical - particularly on the first design of the retainer which fits pretty much flush. It takes a lot of pressure to seat the double race - I pushed mine tight up against the shim with quite a bit of force and I can't see it working loose. I did have to put a speedi sleeve on the yoke. Not an easy job.

mapleleaf, that is what I gather from the manual. Now, if the assembly is just behind that race, I would think that the shaft would be pretty snug in there. With the yoke and the retainer removed, the shaft can flop around. Why is that?

I think it is a bit floppy because it is a big double bearing that supports it and they are loose after it is taken apart. Mine was loose as well when it just laid in the bearing before tightening as the end of the pinion it is only supported by the little end bearing in the differential housing ..when you assemble it and torque that pinion nut up to 200+ Ft lbs it will come together tightly - the spacer between the pinion bearings gives it the critical tolerances and is matched to the bearing assembly.

Interesting, the older HO52s also had an additional spacer right behind the yoke but this was eliminated in the newer design. Check out my older post on this if you are interested,

Just my take on it. I'm no expert....

I installed my new seal in the bearing retainer today. I bought a perfect tool for the job at Home Depot, in the plumbing department. It is an ABS 3" to 2" transition bushing. The outside diameter doesn't quite fit into the seal bore in the housing but it has a radius that seats nicely in the chamfer at the top of the bore.

I have a bunch of old GM tools that my ex-GM mechanice neighbour left me, one fit the seal perfectly.

Wow, you must have some real treasures. I have a few tools that I inherited from my father-in-law. His friend was a mechanic in the good old days. I take good care of them.