Lower differential stud

[UAB62]

Hi

Whilst out having a drive I heard a bang from the back end. It turns out the long diff stud has snapped in two.

My questions are how easy is it to replace? What else should I check or change? From what year did they change to the stepped stud? It looks like this one is not stepped but I won’t know for sure until no get it all out.

Any advice is much appreciated 

[EXCEL V8]

I've heard of this happening before, but not seen it.  Very easy to change.  I think the stepped studs are a series 2 modification - you need the corresponding lower links as well - the bush size is different.  I believe the stepped studs were introduced to combat NVH, not due to the earlier ones failing.

Pete

[UAB62]

18 hours ago, EXCEL V8 said:

I've heard of this happening before, but not seen it.  Very easy to change.  I think the stepped studs are a series 2 modification - you need the corresponding lower links as well - the bush size is different.  I believe the stepped studs were introduced to combat NVH, not due to the earlier ones failing.

Pete

Thanks Pete,

Would you say its best to change both sides as this one has failed? I've read some horror stories about refitting the bushes, do you have any tips?

Simon

[EXCEL V8]

I would definitely change both sides - they are over 40 years old! 🙂.  Replacing the diff mounting bushes is very straight forward - they just sit in their respective cups.  What is important is that the front ones are fitted and tightened first - then you can check the gap behind the diff rear/lower mount and the bush to assess the shims needed to take up any space on the studs - it's covered in the service notes I think.  Once you have decided on the shim thickness to can slacken the front mounts again to aid in inserting the studs at the rear - use some anti-seize.  Replace the lower link bushes as well - preferably with original style rubber ones.

Since the diff is almost out once you have removed the studs I would take the opportunity to service the handbrake mechanism - you will never get a better chance! 

Pete

[Dunc]

Sorry - I missed this thread when it was originally posted, so will chime in with my tuppence worth for future readers, as I've been through the above before.

Stepped studs was VERY late S2. Early S2's like my v8 are exactly the same stud as the S1.

The studs snap when the stud corrodes onto the bits that rotate with the suspension. You might hear  some funny creaking noises from the suspension in the early stages (I did). Its a recip hacksaw job to cut through the rest of the stud and remove. With some heat, the remaining stud did chap through the diff lugs for removal.

Like the long bolt on the hub carrier, regular lubrication is key to avoid it happening again. Be liberal with grease/anti seize whenever you have this bit off.

Refitting the bushes on the radius rods is a horrible job, of which I clearly have zero expertise. I have heard 2nd hand that lotus bits have a rather natty press and technique for replacing them, and if your within shouting distance of them, would suggest removing the rods and getting them all nicely done. I used massive penny washers on mine, but was still not happy with the final result.

Take care with labelling the radius rods, as despite appearances, I believe they are handed.