So the repair is all done, new oil in the diff all I need to do now is drive the car and see if the leak has stopped. A few photos of the repair process:
Having drained the diff of oil, cleaned up around the leak with wire brush to remove old paint and then throughly washed with cellulose thinners, including brushing into the plug weld that was leaking. Looking at the state of the other weld I decided to cover both with JB Weld.
![[Linked Image]](https://www.tm-img.com/images/2020/05/27/diff5sml.md.jpg)
Once fully dried I checked to see there was no more oil seepage then applied the JB Weld over the whole area - one layer, let it cure for 5 hours then a second layer.
![[Linked Image]](https://www.tm-img.com/images/2020/05/27/diff6sml.md.jpg)
The next day, after the JB Weld was cured I wire brushed and sanded the surface.
![[Linked Image]](https://www.tm-img.com/images/2020/05/27/diff7sml.md.jpg)
Cleaned the surface with soapy water and rinsed off, left to dry then grey primer over the area.
![[Linked Image]](https://www.tm-img.com/images/2020/05/27/diff10sml.md.jpg)
After 6 hours drying time I painted the area with Smooth Hammerite.
![[Linked Image]](https://www.tm-img.com/images/2020/05/27/diff11sml.md.jpg)
So I'll see how it holds up over the coming weeks. If it leaks again I'll have to strip it all back and see a welding specialist.
I did contact JB Engineering about this and he replied:
They are always a problem....
It could be welded, but the issue is the cast centre section does not like to be welded, and is the reason why they sometimes leak. If you want to leave the axle in the car I would use a black tiger seal sealing compound, which you can push into the leaking hole and then smooth over with a wet cloth. This should seal as long as it is clean and dry first.
If you wanted it to be welded, it could be done. I would need to burn off any paint that may be in the hole so that the weld can seal the hole correctly.