Series 3 Rear Diff Leaking

I currently have my SWB rear axle removed and have welded on a new diff pan replacing the one which had rusted through. I removed the diff to do this, and replaced the pinion seal that the same time. I am now re-painting the axle before fitting new springs and refitting to the vehicle. I left the axle diff pan down with oil in it to check the integrity of my weld, and it made me happy by not leaking. I then turned it pinion side down to paint it and it is leaking from that side.
On a closer inspection the neither the new pinion seal or the new diff-casing gasket are leaking. The leak appears to be coming from the studs holding the diff to the axle and working its way down past the nut. Has anyone else come across this problem and has a miracle cure?
I am fairly sure it did not leak from there before dismantling but it is difficult to say as I was running a total loss system due to the holes in the diff pan and everything was covered in oil.

Did you put the diff gasket on dry? On similar problem leaks and not wanting to dismantle again I have used a fiber washer under the steel washer to effect a seal. If it is one of the upper studs it probabaly wont leak when axle is in normal position.

Good point, it may not be getting past the gasket but along a stud/nut. Copper washers or some thread seal if that's it?

rob1miles said:

Good point, it may not be getting past the gasket but along a stud/nut. Copper washers or some thread seal if that's it?

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It is definitly coming along the studs rather than past the gasket. Unfortunatly it is doing it on most of them rather than just the top ones. I will try and find some fibre washers to act as a seal.

Wrong thread sorry.

As it is a rear axle and you only have to slip out the half shafts to remove the diff,then I would take it off and reseal.

I had a leak around one of the thermostat studs, took the nut off and pushed some plumbers thread seal in, worked a treat.

rob1miles said:

I had a leak around one of the thermostat studs, took the nut off and pushed some plumbers thread seal in, worked a treat.

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That might be the best idea as it is only along the studs it is leaking, nowhere around the gasket is there any sign of oil so I am happy this has sealed properly. Might use instant gasket rather then plumbers mate though as it is oil not water.

tottot said:

As it is a rear axle and you only have to slip out the half shafts to remove the diff,then I would take it off and reseal.

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I am happy to do this as it is currently off the vehicle being painted so is very easy to remove again. How would you go about resealing if it if I removed the diff again?

Are the nuts tight as those studs are flanged and pulled in according to parts book.

The nuts are tight. I could not find a torque setting for them, but they were as tight as I was happy to go without risking stripping them. They are flanged studs, I replaced one of them that fell out when removed, the new one was nice a tight fit and needed pulling into place.