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I replaced one of my pinion seals with an NOS one. It came sealed and it appeared to be in great shape. I soaked it in neatsfoot oil for a couple of days and I also replaced the companion flange, so I had high hopes. Alas, after a few weeks it started leaking and after a few months fluid dripped even when the truck was sitting idle and after cooling down.

I replaced it again, but this time I bought a modern seal and adapter from MSeries Rebuild. I think this may be the way to go. The modern seal is smaller than the original and it fits in an adapter made by Mseries. The adapter ring has threaded holes so it can be removed much easier than the original seals, which are bears to take out. Alternatively, the seal can be removed without removing the adapter.

The method I would recommend for removing the old seal is to drill a few holes in it, thread the holes, screw in some bolts, and then use a slide hammer on the bolts.

Chris,

Thanks for the info. In regards to NOS seals I think Charles has done a great job convincing people (especially me) of the pitfalls of using NOS seals. Certainly works for some, but common sense tells you the "O" in NOS is not a good thing for seals. Time and technology march on.

regards,
bob

Chris P wrote:I replaced one of my pinion seals with an NOS one. It came sealed and it appeared to be in great shape. I soaked it in neatsfoot oil for a couple of days and I also replaced the companion flange, so I had high hopes. Alas, after a few weeks it started leaking and after a few months fluid dripped even when the truck was sitting idle and after cooling down.

I replaced it again, but this time I bought a modern seal and adapter from MSeries Rebuild. I think this may be the way to go. The modern seal is smaller than the original and it fits in an adapter made by Mseries. The adapter ring has threaded holes so it can be removed much easier than the original seals, which are bears to take out. Alternatively, the seal can be removed without removing the adapter.

The method I would recommend for removing the old seal is to drill a few holes in it, thread the holes, screw in some bolts, and then use a slide hammer on the bolts.

How many miles you got on the new seal?

The NOS one had less than 50 miles on it before it started leaking. I just installed the one from MSeries, so we have yet to see how long it lasts, but it's a new modrn seal so I expect it will be fine. If it does start leaking I'll post here again.

Charles,
If you happen to see this could you reply with the part number for the modern seal that fits in the outer sleave than Mseries builds? I should have written it down before I installed mine and I'd like to know what it was in case I ever have to replace it.
Thanks

I have had Charles pinion seal kit in my truck for over a year. So far so good. I went the NOS route first, like the OP soaked the seal and burnished the leather with a brass rod and I installed a speedi-sleeve on the companion flange. It lasted all of 200 miles, and when it let go, it seemed worse than the old one I had removed. The good news was that it came out very easily the second time, hadn't been in 8 months. The kit from Charles went in fine, put the speedi sleeve on the companion flange and it's been dry for over a year. Regardless of which seal, you really need to use a speedi-sleeve on the companion flange even if you can't see evidence of wear. The sleeve is harder which will take longer to wear to the point of leaking.

As the OP, I'd suggest using Charles kit for any pinion seal repair if you intend on driving the truck. If you're just going to drive it on and off a trailer and want the perfect restoration, I've still got a spare NOS, good luck!