Todays disaster !!

[David B]

When I removed my diff during the rear suspension overhaul I strengthened the extension as it was simply done with everything out. Before welding I noticed that the welds from the tube section to the flanges were very poor with severe undercuts. Having seen quite a few similar extensions this seems to be a common problem. Certainly jacking up via the diff, if done correctly should not be a problem.

David

[dasadrew]

When I removed my diff during the rear suspension overhaul I strengthened the extension as it was simply done with everything out. Before welding I noticed that the welds from the tube section to the flanges were very poor with severe undercuts. Having seen quite a few similar extensions this seems to be a common problem. Certainly jacking up via the diff, if done correctly should not be a problem.

David

Spot on! I reckon the breakages are not due to poor design but to poor manufacturing. Mine also had loads of undercuts and there is even a section without any weld bead at all. Of course, it's also a bad design which doesn't lend itself to being able to be manufactured correctly!

[staggering]

Guys - I plan to strip down as much as needed to replace the diff extension, nose, quill shaft etc this weekend. Just had a look and already confused as where to safely support the car on jacks. The problem I can see is that 4 large bolts holding the ext piece to the swinging arms (when their removed) will make everything swing loosely and when (eventually) I try to put things back together it will be difficult to line up a heavy diff / extension piece etc while trying to line these bolts up.
Apologies if this isn't very clear, just wondered if anyone has done this without removing the swing arms etc and, if so, where best to place wood blocks / jacks etc

Many Thanks
Ian

[john 4d]

Ian,
From my "diff oil leak" post.
"I've now had to remove the extension housing from the suspension arms, the one joint I wanted to avoid disturbing. With the car supported at the rear seat heel panel, the rear wheels (a stack of three bricks under each rear tyre) supported at the height just below their load carrying point and the two diagonal arms supported by a single cross beam of wood (2"X2"X24") on my trolley jack I loosened and removed the four bolts and lifted the housing clear with no drama. I amazed how easy that was."
I should have taken photo's. The sub frame and swing arms stay in place, everything is supported. I just tried to guesstimate which way the different elements of the sub frame assembly would want to move if I removed the 4 ext piece bolts, and supported accordingly to counter the move, I guess I got it right, nothing moved. I was able to pull the bolts free by hand! Today I refitted my un-modified extension section followed by the diff, just as easy! Tomorrow, weather permitting, its just a matter of reconnecting the prop and driven shafts and refitting the tail sections of the exhaust and the silencer/tail pipes (the hardest job of all, refitting the rubbers over the hanger hooks).
John4D

[cosmicwheels]

Hi All just brought this back to the top, have just been checking the oil in the diff and noticed nose extn weld is cracked half way round, will replace with a LDparts one,just to say it is worth looking from time to time to see if its started to spit.John

[Lingen]

I reckon this is caused by jacking up the rear of the car under the extension / front of the diff, which looks a suitable place, but in fact puts a great strain on the area where the fracture always occurs. It just isn't strong enough there to take the weight. A strengthened extension is a wise choice, and then only jack the car at the rear of the diff under the back mounting plate. If the plate is looking tired, then only lift one side at a time!

[staggering]

Lingen, All - just out of interest, in all my 15 years of owning this Stag, I have never jacked it up from the diff (don't know about POs) - perhaps I've been on borrowed time 'til this failure

Regards
Ian