Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Salisbury diff

I would also thoroughly recommend JB Engineering, Billy did an excellent job of rebuilding my 7HA and installing a Quaife ATB diff into it.

And JB weld is also flippin' brilliant stuff - although you'd have to do a significant amount of degreasing to get the area clean enough to seal I would think.

But at the end of the day, is it really worth all the hassle simply to prevent your Morgan from being able to mark his spot?

I am concerned that the epoxy may not take properly as the oil is seeping out of the weld, and as much as I clean it the oil could continue to seep before the epoxy sets off. I'll contact JB and see what they have to say about it. Thanks for the info.

I reckon if you jack that side up, drain the diff (takes about 1.1litres) and then apply some mild heat to the outside, you could get it dry enough to work.

It's only my opinion but I would never just seal a leak.

I would want to know why it's leaking as it could be a symptom of something more serious. Then again it might not but I am a firm believer in root cause analysis wherever possible. (Which can be a lot of fun on a Morgan)

One possible cause could be that there is a very slight amount of flex in the diff housing to tube joint which might have started a crack around the weld and just applying sealer to that would allow the flex to continue. Of course that is the pessimists worst case scenario but it can happen.

I might be tempted to clean all the paint off in the area then use a dye penetrant crack detector to rule out that possibility.

As far as you know, is this a new leak or has it always done it?

To me it's a new leak, but then I've only had the car since last August, and with the winter months and now lockdown I haven't covered many miles in the car. I have done some reading up and it seems a dodgy plug weld is not uncommon. I'm leaning towards a thorough clean up, delicate grinding of the weld and surrounding casting and applying two coats of JB weld. If that doesn't do the job then it will be off to a welding specialist who can weld the steel weld to the cast casing.

The housings are cast steel not iron so it doesn’t necessarily need a specialist
I’ve welded up countless differential casings and retubed axles over the years
I did the axle for the Peking Paris car...
The trick is to pre heat the cast part and not to let it cool too quickly

The more I thought about it the more I think you need a professional opinion. If the weld is there to hold some internal part in place, and now that weld is cracked, there may be more concern about the long term health of the differential. I think a strong repair is important and I don't know enough about JB Weld to suggest that as the right move.

I'd go along with that. Those diffs are as rare as hens' teeth.

That's a large part of the reason I went to a Quaife ATB.

the welds are there to hold the tubes into the casting. They were not slways good welds. Tubes have been known to pull out. If it's really in question have someone familiar with these axles check it out.