Late GT6 Mk 3 - Non-Rotoflex - Wrong rear spring?

[Kevin Atkins]

Progress.. I've managed to extract the centre stud from the differential (the Laser stud extractor worked brilliantly, thanks for the recommendation) and have built the new rear spring up with the pivot box etc (that was a pig of a job..) I've fashioned plugs from a couple of the old studs to go in the two redundant holes on the differential and the spring is ready to go in. Question - the bottom plate sits a little higher than the mounting face on the diff, do I need to add spacers / washers to the studs to fill the gap, or am I OK to just tighten the whole spring box + spring down?

[GrahamB]

When fitting a new swing spring to my Spitfire, I bent the bar on my vice squeezing the spring into the pivot box so I know what you mean by a pig of a job.  Once mounted on the studs, I added a 1/2 inch spacer from Canley Classics under the spring so as to give the desired degree of negative camber and tightened the nuts so that everything was securely seated on the diff.  The spacer is machined so as to support the whole area under the bottom plate.  Adding washers to the studs sounds a bad idea.  I would tighten the nuts progressively until the bottom plate is securely seated on the diff.

[NonMember]

8 hours ago, Kevin Atkins said:

the bottom plate sits a little higher than the mounting face on the diff, do I need to add spacers / washers to the studs to fill the gap

The bottom plate of the pivot box serves to clamp the bottom leaf into the slot in the diff. It's actually supposed to have a tiny clearance from the upper faces so that the spring leaf is properly clamped.

[Kevin Atkins]

Thanks for all the help folks. I got the spring fitted.. now that the car is back on its wheels, and having rolled it to settle the suspension, it's looking far too high at the back with lots of positive camber.. it looks like it needs to come down at least a couple of inches. I haven't actually driven the car yet so it might settle a bit, but I'm doubtful it's likely to settle to anything like the correct ride height - see the attached image. I'm reasonably certain the driveshafts are the longer ones -  I measured then at 20.5".

Question then - I was thinking of perhaps removing some of the inter-leave button spacers, maybe one layer at a time, and see if I can drop it that way. Is that OK to do? Failing that, could I use a spacer block with the swing-spring suspension? It looks like it should be possible but I'm not sure..

I've gone from one extreme to the other - previously it was dragging its rear end with wheels splayed out and negative camber - to this.. and if nothing else, it looks ridiculous so I need to fix it somehow!

 

 

[NonMember]

I suspect it's a bad idea to remove the buttons. It will result in metal-to-metal contact which will squeak and boing and all sorts, not to mention the wear.

As far as I know, the lowering blocks work fine with a swing spring but you may well need longer studs.

[johny]

It will sag and probably quite a lot initially but whether it'll be enough is something else. There were the stories of the old days when people drove around with sacks of sand in the back to encourage the process...

[Kevin Atkins]

OK thanks - bag or two of cement it is then to begin with, see if she settles down, otherwise I'll look at adding a lowering block.

[GrahamB]

The rear suspension does settle quite a bit after a few miles even without the extra ballast.  I used the 1/2 spacer, the smallest size available, in order to obtain slightly more negative camber and it works perfectly.  You can fit this spacer with the standard studs (on a Spitfire) but I have read that longer studs are required for the thicker spacers.

[Kevin Atkins]

Just a quick footnote - so the car is running again; I've driven it a few miles and the rear suspension has settled a bit so I'll see how it goes over the next week or two. Thanks for all the help and encouragement here.. Now I need to get the carbs set up properly so I'll do a bit of a search on here and if necessary I'll ask in the appropriate place! Cheers all.