Lotus Elan

Noise from rear suspension - Adjusting spring abutment plate

PostPost by: stugilmour » Sat Aug 11, 2012 4:45 pm

The recent thread on Elan rear suspension noise here got me looking my car over, and my problem is different.

elan-f14/rear-strut-noise-t25848.html

Turns out on the right side of my car the top spring abutment plate is contacting the body, causing a thump over bumps. I think The ear that seems to be designed to retain the end of the stock spring needs to be rotated about 90 degrees or so to prevent body contact (similar the left side of my car that doesn't have the noise problem).

My Spyder supplied replacement full diameter springs (fitted to stock hub carriers) look a bit different from the stock ones in the parts book; the last 1_1/2 or 2 coils at both ends of the spring are close together and the spring end is flush with the coil outside diameter, so the spring end does not seat into the ears on the top and bottom abutment plates. I already know my top abutment plate hole is rounded as I have to constrain the shock shaft to tighten the Nyloc at the Lotocone, so thinking I can simply rotate the top abutment plate and problem solved.

So, before I screw things up further, can someone confirm I can reduce the spring pressure at full suspension droop and possibly rotate the top abutment plate? I have had the assembly apart before to service the diff, but can't remember how much I had to disassemble to get the shock top bolt and spring hanging loose. Will I need to undo the wishbone bolts and CV output shafts from the hub carrier to free everything up, or will the spring pressure typically be released at full droop with all that stuff connected? Will I screw anything up by simply trying to lower the wishbone and hub carrier on a floor jack with the body securely raised, and answer my own question/concern? I have visions in my head of flying springs, so thought it worth asking the collective experts first. :)

Thanks in advance. If I get it to work I will post results. Something to watch for if you have the body off, as the correct top abutment plate position is not obvious when looking at just the built up frame. Thinking with stock springs it sort of takes care of itself with the spring ends seated in the ears at both ends and everything ending up correctly clocked and symmetrical side to side to avoid body contact.
Stu
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PostPost by: stugilmour » Sat Aug 11, 2012 9:29 pm

I managed to get the spring abutment plates moved to a better orientation. Here is what I did:

  • Jacked up the car on the wishbone.
  • Supported the body on the rear floor area.
  • I used straps to squeeze and constrain the springs enough so that they were not touching the top abutment plate, as inspired by Gary's pics here:
    elan-f14/sows-ear-chassis-t24752-45.html
  • Loosened the top bolt from the shock and rotated the plates.
  • Jacked up the wishbone to sort of half seat the spring back in the abutment plate.
  • Loosened the straps and banged the springs into their seats.
  • Tightened up the shock top bolt, put the wheel back on and lowered the car.

Still have some sort of noise back there but it is better. Maybe things will rattle about and simmer down.

Cheers!
Stu
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PostPost by: stugilmour » Sun Aug 12, 2012 1:51 am

After a run the noise is much better. I expect a few bumps have seated things a bit better, and driven the bump stop rubber up to the abutment plate reducing rattling. I think having the 'D' shape worn out of the abutment plate on one side of the car should get attention next winter, but calling it good for now. :)
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