Author Topic: Front suspension lower wishbones & Upright  (Read 476 times)

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Offline Certified Lotus

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Re: Front suspension lower wishbones
« Reply #15 on: Tuesday,January 02, 2018, 02:48:20 AM »
If it twists when turned the upright is bent.  Replace both the left and right with new would be my advice.

JB, that is what I thought. But I had another upright from a different Europa and installed that one ( yes, it was the right side upright) and it did the same thing. Two bent uprights? Possible but that is somewhat unusual.

Offline Certified Lotus

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Re: Front suspension lower wishbones
« Reply #16 on: Tuesday,January 02, 2018, 02:52:15 AM »
I'm not sure I understand what's happening. You turn the upright (vertical link) as though you are making a turn and that twists both lower A-arms? Is the twist along the length of the A-arm halves (as though you're rolling up a newspaper)? I assume you didn't over "tighten" the trunnion so that you ran out of travel. If you disconnect the upright from the lower A-arms and turn the upright while holding the trunnion, what happens? Does the trunnion move or does the upright just turn? If it moves, the upright is bent as JB says.

BDA, yes the lower A-Arms twist. No the trunnion isn’t over tightened. I even backed it off one more full rotation just to test. Did same thing. The upright turns freely when removed from the A-arms, no binding at all.

Offline Certified Lotus

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Re: Front suspension lower wishbones
« Reply #17 on: Tuesday,January 02, 2018, 03:08:02 AM »
I can't tell what's wrong with your set-up but if that shot is the set-up with tightened bolts then I think I'd be getting some shim washers between the arms and lower damper mount.  Otherwise you'll never get the correct torque (or A-arm rigidity) on the damper bolt.

It might be that the bush isn't long enough or the arms are bent, but if either ends of the arms are tight (chassis/Trunnion) then I be thinking of the bush length. I would imagine the damper bush and it's steel insert should be the same dimension as the steel insert in the trunnion nylon bushes ?

Brian

Edit to add.....    on the twisting aspect, my first thought was as BDA says, that you've screwed the trunnion too far on the upright causing it to lock up. If not that then I'd be going for a bent upright, but if you've tried 2 seperate uprights now, that idea becomes less likely (unless you are lucky enough to have 2 bent uprights  ;)  )

Brian, the photo I shot was of the a-arms unbolted (I have dismantled the right side suspension multiple times to try and figure out what is wrong). Remember, I have the left side installed and it works perfectly. The trunnion and the damper bushing are the same width, 39mm. The lower a-arms are OEM NOS.

As everyone has suggested, the upright(s) is probably bent. Two of them is very unusual but I’m running out of other possible options. I’ll order a new right side and see what happens.

Offline jbcollier

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Re: Front suspension lower wishbones
« Reply #18 on: Tuesday,January 02, 2018, 07:51:20 AM »
The uprights are actually very easy to bend.  One good curbing and they would be done.  For that reason, always replace with new.  Rimmer Bros usually always have them in stock.

Warning: Notice of Shakey Ground

I believe the later uprights maintain the same geometry.  They are stronger which of course means that more force is then applied to the chassis in a curbing situation.

Offline Certified Lotus

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Re: Front suspension lower wishbones
« Reply #19 on: Sunday,January 07, 2018, 01:52:50 PM »
Final end of the chapter on the mystery of twisting lower wishbones (a-arms). JB (and others) were right. It was a bent vertical link (upright). I bought a new one for the right side from RD Enterprises, removed the old upright and installed the new one. No twisting of wishbones!

The first photo is of the new upright installed without the stub axle bolted on. The second photo is of the old upright with the new upright behind it. You can clearly see it was bent.

I had two right side uprights so I put them next to each other ( the third and fourth photos).  Amazing, one upright is bent at the threaded end and the other upright is bent at the top end. Two bent right side uprights.......and they were from separate cars. 

Prepping and painting the new upright for installation. And now I know that the lower a-arms don't have trailing and leading parts (just the uppers do).

Learned something new from this experience.
« Last Edit: Monday,January 08, 2018, 04:07:59 PM by Certified Lotus »

Offline BDA

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Re: Front suspension lower wishbones & Upright
« Reply #20 on: Monday,January 08, 2018, 05:38:28 PM »
Yup, They're bent! Glad you got it sorted out.