Dana 35 front diff pinion seal help...

[CamTheHedgehog]

Alright. I am posting this because I have genuinely run out of ideas.

Two days ago, I swapped out my front diff for a "new" one, that I had cleaned, inspected, and resealed. It has all new National seals, part numbers verified and everything. In hindsight, this was a bad idea.... This is the second bad experience I have had with National, who is supposed to be the "good" brand for oil seals.

Today, I look under the truck, and.... there is one single drop of oil at the bottom of the pinion seal. The one I just replaced. On the diff I just spent my Saturday installing.

Does anyone have any ideas? Seal brand recommendations, methods, anything? This is really starting to tick me off, I want this stupid axle to stop leaking.... sigh...

 

[franklin2]

Pull the driveshaft, and then loosen the nut and pull the yoke off. Look around the outside of the yoke. If it has a little groove where the old seal had been running for years, that can cause a leak.

 

[Uncle Gump]

How certain are you the housing wasn't damaged? Imperfections in the bore course cause leaks around the outside of the seal. Just a tiny smear of RTV can correct that.

I usually wipe a bit of a good quality all purpose grease on the seal lip... nobody likes a dry rubbing.

Also... did you clean/polish the sealing surface of the yoke? A bit of Emory cloth or the like to clean it up... then give it the finger nail test. I've seen several have a hard dirt line that can cause problems.

 

[CamTheHedgehog]

How certain are you the housing wasn't damaged? Imperfections in the bore course cause leaks around the outside of the seal. Just a tiny smear of RTV can correct that.

I usually wipe a bit of a good quality all purpose grease on the seal lip... nobody likes a dry rubbing.

Also... did you clean/polish the sealing surface of the yoke? A bit of Emory cloth or the like to clean it up... then give it the finger nail test. I've seen several have a hard dirt line that can cause problems.

I checked before I installed the seal, and also put a smear of RTV around the edge, that has just become common practice for me.

I did recondition the sealing surface, there was quite a groove. Worked my way through the sandpaper grits, and a final polish with some brasso and a rag, nothing too crazy.There was still a bit of a groove, but i had removed quite a bit of material and i didn't want the diameter to reduce to the point where the seal wouldn't seal anymore. It was minor, but still detectable under the fingernail... that may be my problem. I am leaning towards buying an OEM ford seal, as well as a new pinion yoke so it has a fresh surface.

Both of those parts would only be about $70 total. I just want this stupid diff to stop leaking!

 

[Uncle Gump]

Just get the new yoke...

 

[CamTheHedgehog]

I just did, after typing that message out. It made the most sense, especially with the time it will save me.

Thank you all for your input.

If only I had thought this through before re-assembling the differential...

 

[pjtoledo]

I'm going to try shifting the wear groove by putting a machine bushing behind the yolk.
that will push the yolk out about 1/16"

 

[franklin2]

I'm going to try shifting the wear groove by putting a machine bushing behind the yolk.
that will push the yolk out about 1/16"

Can you push the seal in a little further? Sometimes when China makes these seals a little different, they will ride in a different spot. So I guess when they foul this part up it can be a good thing.

 

[pjtoledo]

technically yes, ( I have lots of hammers) but the results won't be optimal.

I do mount the yolks in a vise and attempt to polish the surface with very fine paper and compound.
a thick shoestring applies even pressure and gives you a workout.

 

[CamTheHedgehog]

New yoke and seal are here. Waiting for a day when the garage is open.


I have also discovered that both axle shaft seals are leaking.
Yeah, I'm not happy about it.

I suspect it is for the same reason as the pinion- partially because they aren't ford seals, and partially because there is a seal groove in each CV joint that I was unable to remove with some fine sandpaper.
So new axles it is.
I would order OEM CV axles, as they are a decent price at the local dealer, but they are on perpetual backorder. Guess I'm going with RockAuto special ones, probably TrakMotive as I have had good luck on other vehicles with their axles.

 

[franklin2]

I looked back through the thread and didn't see it. Did anyone ask you about the vent for the axle? If it's plugged, all the seals will leak.

 

[CamTheHedgehog]

I made sure to blow out the tube before I reinstalled it and there didn’t appear to be any blockages.

 

[Shran]

Man... are they puking oil or just seeping a little?

I don't like drips or puddles and will fix those, but I'm kind of at the point where I just don't care about really small leaks/seeps. Just not worth the time or money to fix them.

 

[franklin2]

I made sure to blow out the tube before I reinstalled it and there didn’t appear to be any blockages.

That includes the fitting on the pumpkin? Not sure what your setup looks like, but on the rearends the fitting that had the brakeline tee has a hollow bolt that serves as the vent. That small hole in the hollow bolt loves to clog up.

 

[CamTheHedgehog]

That includes the fitting on the pumpkin? Not sure what your setup looks like, but on the rearends the fitting that had the brakeline tee has a hollow bolt that serves as the vent. That small hole in the hollow bolt loves to clog up.

I didn’t check that…. I assumed it was clear.