How to build your own rear diff casing.

Well after my rear diff decided to fall apart and destroy the diff casing I decided to build a new slightly heavier duty casing, I know there are various company's who produce HD diff pans off the shelf but there's something satisfying about making your own parts and saving some money while you go.

Here's what I started off with: basically the circlips which hold the centre diff pin in fail causing the pin to fall out and punch a hole in the diff pan, this can be seen at the bottom of the tear! In the picture below, Then I kept driving and the gears which fell out tearing the pan wide open.


So here's what i started with today:


Start by flushing out the gas bottle so you know there's no chance of an explosion when you start cutting.


Next cut off the old diff pan and buff away the welds and any remainjng material on the axle and use it as a rough guide for a diameter to cut the bottom of the gas cylinder.




Now you will need to decide how far out you need the base of the gas cylinder to sit from the axle. Iv worked mine out to be 55mm so I masked off a 55m band around the gas bottle and cut right round the bottle



Now use a small ratchet or similar to reduce the size of the ring until its the right diameter to suit your new pan, then mark and cut off the excess and weld it so you have a large hoop.



Both these parts can now be fully welded to the axle


Next you need to cut out and weld in the fill/level plug



And the jobs done, just need to give the axle a really good clean out and paint and fit all your parts.

We also had the circlips removed and the diff pin welded up in the new diff so there's no chance if it failing for the same reason again. Will add the picture when I find it.


Hope this can help some people.

Cheers mark

Not a bad idea and thumbs up from someone who likes to save money!!

Haha, epic mod!!

JUST make sure it doesnt foul the tank/tank guard!

Otherwise, top job, love it

Mr Noisy said:

Haha, epic mod!!

JUST make sure it doesnt foul the tank/tank guard!

Otherwise, top job, love it

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Well that would be annoying! Haha. It doesn't stick out any more than the original so fingers crossed, a new tank guard/detachable tow bar is one of the next items on my list so worst case ill make it work.

Cheers mark

Nice job, I like that

Thanks.

Nice one! What a niffty idea.

bit different to using it for a fire in the garden ( the bottle) good mod and good effort too

Crackin' idea, Gromit!

Cheers guys. Still to check it works, I'm waiting on my diff coming back from the welders but I can't see there being a problem with anything. It will hold a bit more oil but that's about it.

Cheers.

will you be sealing it or is it 100% leak proof welding?

I'm hoping its leak proof, iv not tested it yet.

Nothing a few costs of paint won't stop ;-) haha

Mark

Paulmitchell1984 said:

will you be sealing it or is it 100% leak proof welding?

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Mark151151 said:

I'm hoping its leak proof, iv not tested it yet.

Nothing a few costs of paint won't stop ;-) haha

Mark

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good looking welds.......... doubt it will leak

Thanks man, Im no welder but my logic was to set the heat pretty high on the welder hoping for better penetration rather than a neat weld which I would need to seal over.

Mark

Yep you need a lot of heat for welding that kind if thickness, and if it doesn't penetrate good you've kinda wasted your time.

Neatness and heat don't really go hand in hand, cleanliness makes neatness, but your work generally looks spot on so id be surprised if it leaked.

Better than an axle I once bought that had had a standard pan on it and was obviously not well done and was then caked in body filler under the paint.

Went from a quick wire brush and tidy up to throwing the axle in scrap!!!

Mr Noisy said:

Yep you need a lot of heat for welding that kind if thickness, and if it doesn't penetrate good you've kinda wasted your time.

Neatness and heat don't really go hand in hand, cleanliness makes neatness, but your work generally looks spot on so id be surprised if it leaked.

Better than an axle I once bought that had had a standard pan on it and was obviously not well done and was then caked in body filler under the paint.

Went from a quick wire brush and tidy up to throwing the axle in scrap!!!

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Seeing it sounds like you know a lot about welding do you know what would cause the weld round the band to the axle casing to rust over instantly? I couldn't tell why it was doing it as everything was cleaned off properly.

I know what you mean about the sealer, I have a couple here with it on, one we bought like that and the other is currently on my car as a temporary axle. I can't remember the brand but it was a 2 part plastic metal compound. Just mix it up and paste it over the holes. In fairness it's lasted 3 hard days out snd a bit if road driving, I can't see it lasting much longer tho.

Cheers mark

Not a welding expert mark just done a fair bit, land rover thing

The rust is maybe because its bright bare metal and it is hot perhaps!

Usually welds last a day or so before rusting so not sure pal im afraid!

Ach well thanks anyway. I'm not too fussed, it only done it on the weld to the axle, the weld between my band and the convex bit was fine. Just thought it was odd how fast it changed.
Don't think it's effected the strength as I was giving it a few pretty hard hits shaping it to suit the convex bit as I was tacking it on.

Mark

Maybe it was a little oil contamination?

Amazing how fast it spreads when warm!

That could make sense, i only buffed the outside clean the inside was still oily so with the heat of the welding it could have vaporised or ran down into the seam.

Oh we'll its done now and doesn't look like its going anywhere in a hurry. Going to fab a diff guard/ rock slider to go on it once its back on the car.