Differential Oil leak...

[1955cj5]

This has been ongoing...

I previously plugged it externally but now have most of it apart and want to repair it correctly...

I replaced the bolts with new from Brattons using permatex #2 but it still leaks, even with the oil drained as completely as it will drain...

It looks like, with the hub off, I can remove the front two backing plate bolts, which will release the rear radius rod on that side, and I can slide the axle housing and backing plate off as a unit after releasing the brake rods...

Then I can replace the gasket and hopefully stop my leak....I have two different thickness gaskets..

I will try to match the thickness of the gasket that is (I hope) already in there...

Should I put sealant on the gasket?

What type?

Any other thoughts?

Thanks,

Randy

[daveymc29]

Don't just guess at the thickness of the gaskets, use a micrometer and replace them with gaskets of the same thickness from the side they were on. I use the non-hardening permitted on the gaskets and on the "cleaned: metal surfaces. Light coats but even. Same with the bolts that hold it together, then tighten them snugly but not excessively. Clean is the operative word on these surfaces, I was them off with lacquer thinner and rub any suspect spots with steel wool or 600 wet or dry paper the rinse and dry. I use lots of paper towels.

[1955cj5]

Thanks Davey...I have a vernier and will check the gaskets...Permatex #2 is the non-hardening stuff....I have some and will use it...

I plan to only pull the one leaky side....the driver's side...

The Bratton's catalog shows 35 ft lbs for the diff bolts...

[Mitch//pa]

use indian head shellack on the gaskets and bolts. make sure all the parts, housings , bolts are clean and dry or you'll be kicking sand.

[BRENT in 10-uh-C]

Something that we have often found that causes these leaks is the housing is bent/tweaked and as such, the gasket surface does not pull-down equally around the perimeter. Spinning the housing in a lathe using a live center into the differential bearing race will confirm this. On some housings, a .010-.020 cut is all it takes to true that surface up, -or sometimes first using heat to straighten the tube. My belief in what causes these housings to bend is from previous owners wrapping a chain around the housing and using the car to pull heavy objects.

[katy]

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Did ours recently w/out sealant, 35 ft-lbs and no leaks.
Your mileage may vary.

[1955cj5]

Originally Posted by katy

Did ours recently w/out sealant, 35 ft-lbs and no leaks.
Your mileage may vary.

I think I'll use sealant....I don't want to do this again....not right away...

[1955cj5]

turns out there is no gasket in this side.......

So maybe just Indian Head Shellac on all the mating surfaces and bolt/banjo threads?


Edit: Closer inspection shows portions of a gasket here and there...no wonder it leaked....Indian Head and new gaskets ought to make a big difference..

[Tom Wesenberg]

The gaskets set the preload on the ring gear bearings, so you can't just add gaskets at random. You could use silicone to seal the flange, and that wouldn't change the preload as long as the tube is bolted up while the sealer is liquid.

[1955cj5]

I will do my best to match the thickness of the sections of the old gasket that were still in there...I have two of the thin and two thick from Brattons, so I ought to be able to get it really close. I'll allow a little for the compression of the old gasket..right now it looks like two thin gaskets will match the old one..

I was planning to use the Indian Head Shellac, never used it before though....

[mshmodela]

Great thread...

http://www.permatex.com/products-2/p...ompound-detail

[Tom Wesenberg]

I also use Indian Head or the Permatex non-hardening sealer.

[Mitch//pa]

i used permatex on the model A diffs and had leaks..
never a prob with indian head the stuff works on these cars if the surfaces are prepped right which is the key to success
make sure you ck the preload

[katy]

How about cleaning it up good, re-assemble with say .020" of gaskets, measure axle assembly end play, and that should give you an idea of how much if any gaskets you need to get the preload correct.

[1955cj5]

The old gasket fragments measure about .007, depending on which piece is measured..

Two of the new gaskets together measure .008.

I will check the preload....I'll assemble without gaskets first and check it and go from there....

[Jim Brierley]

Be careful assembling without gaskets, this can cause warpage like Tom talks about. Before final assembly lay a thin bead of silicone at the lip where the gasket is. I like black RTV.

[1955cj5]

I cleaned everything and fitted it together without gaskets....the axle turned as freely with the housing installed as it did without the housing, it even coasted a little......since the driveshaft/pinion are still installed and attached to the transmission this is all I had to go by...

I was able to get some Indian Head Shellac through the local O'reillys...

So now everything is cleaned sealed and assembled....I am pretty sure it will not leak..

There was very little of the old gasket remaining so there was no seal there...

And I installed the original bolts as the replacements from Bratton's were not shouldered and they went in easily by hand..the old ones tightened up a little about 1/3rd of the way in, so I think they were a better fit...

Time will tell!!

[Tom Wesenberg]

Did you check the rollers carefully? In the center picture, look at the roller at the 2:30 position. It looks galled to me. Maybe it's just a hair or line of grease, but it looks like missing metal.

[Mitch//pa]

are you taking the other trumpet off? did the old bearings spin on the carrier mount? many do. i would never reuse old bearings. you need to remove both sides clean up then start with the pre load settings

[katy]

you need to remove both sides clean up then start with the pre load settings

Ditto