Lotus Elan

Suspension settling after re-assembly?

PostPost by: The Veg » Sat Apr 14, 2018 5:06 pm

Recently I re-assembled the front suspension after installing new bushes, track rod ends and ball joints, rebuilding trunnions, painting the control arms, etc. Of course everything went back on in a drooped position, and I left the control arm mount nuts loose so everything can settle into weighted position before tightening as I've read advised here. I wasn't surprised when the car sat really high when weight first came onto the wheels (looked ready for the Paris-Dakar Rally :mrgreen: ), but after several sharp downward shoves on the wings followed by five days of sitting there wasn't much improvement. The wheels are on dollies with casters so lateral movement isn't inhibited. After those five days I sat on each front wing and bounced my full weight (250-260 lbs.) a few times, alternating between sides for several rounds. It's slightly improved but I've still got a solid 4 inches between the top of the tyre and the wheel arch. The items currently removed from the car do not add up to as much as I weigh -maybe half at best- so that's not a factor. I have not altered the springs or dampers and all the new suspension parts are original type. What am I missing here?
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PostPost by: oldelanman » Sat Apr 14, 2018 5:35 pm

The Veg wrote:I left the control arm mount nuts loose so everything can settle into weighted position before tightening

How about the shock absorber and trunnion to lower wishbone bolts - did you also leave those loose ?
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PostPost by: The Veg » Sun Apr 15, 2018 2:19 pm

Good catch; I didn't- but I loosened them this morning and bounced on the wings again and it has made no difference. I also checked that the casters on the dollies are oriented perpendicular to the car's wheels to make sure that they can accommodate the lateral movement. With my bum on the wing just above the wheel and my feet off the floor, my full body weight will hold the clearance about where it should be, but without me on it the clearance remains like this:

susp_1.jpg and


susp_2.jpg and


And this is how it sat before anything came apart. Maybe slightly higher than ideal, but nothing like now.

susp_3.jpg and
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PostPost by: oldelanman » Sun Apr 15, 2018 3:58 pm

Something definitely not right there. Did you loosen the wishbone pivot nuts again or just the shock absorber and trunnion bolts? You need all the hardware loose at the same time or the suspension will not be able to settle to the normal ride height position before you torque it all up. It is awkward to get to all the hardware with the wheels on and the vehicle on the ground (or trolleys in your case). I did mine with the car on stands and the wheels off - with all hardware loose jack up the hub until the lower wishbone is horizontal (normal ride height position) then torque everything up.
torqueing-suspension-hardware-001.jpg and
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PostPost by: Bud English » Sun Apr 15, 2018 4:51 pm

Did you pre-load the car with the recommended weight (chassis manual) sitting in the recommended positions?
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PostPost by: 69S4 » Sun Apr 15, 2018 5:33 pm

oldelanman wrote:Something definitely not right there. Did you loosen the wishbone pivot nuts again or just the shock absorber and trunnion bolts? You need all the hardware loose at the same time or the suspension will not be able to settle to the normal ride height position before you torque it all up. It is awkward to get to all the hardware with the wheels on and the vehicle on the ground (or trolleys in your case). I did mine with the car on stands and the wheels off - with all hardware loose jack up the hub until the lower wishbone is horizontal (normal ride height position) then torque everything up.
Torqueing suspension hardware 001.jpg



Good advice. I've just done much the same work and faced the same problem. With the wheels on it's almost impossible to get to anything under the car so I jacked the front of mine up until I could get a set of ramps under the front wheels and then let the jack down so it was resting on its wheels on the ramps. It was then high enough that I could get underneath and slacken all the wishbone nuts and everything else off half a turn. Mine settled down about a wheel arch inch on doing this but I'd jacked each side up somewhat first before nipping the nuts up on reassembly, not tightened them on full droop.

If everything is normal the lower wishbones should be pretty much parallel to the bottom of the crossmember. Then just tighten everything back up. If they're not parallel with no strain on the bushes then I'd be looking at the shock absorber units next. If you've not changed them though they shouldn't be doing anything they didn't before but if you removed them it might be possible to get the top mount rubber bushes in the wrong order (ask me how I know!) and that'll increase ride height.
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PostPost by: The Veg » Sun Apr 15, 2018 10:27 pm

Everything was loosened as of my previous post. Just now I've got under it again, ensured again that everything is quite loose, and put the jack under the LF hub and brought it up such that the lower wishbone is almost parallel with the crossmember. I then tightened everything and released the jack. The suspension then shot back down to the same too-far-extended position as before, and when I put the trollied wheel back on the suspension was totally stiff and would not move under my weight at all. The springs sat more extended than usual for several weeks when it was all apart, but that shouldn't damage them, should it? Could the damper have been somehow damaged from being off weight for too long? I'm out of ideas.
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PostPost by: mbell » Sun Apr 15, 2018 11:39 pm

Personally I think this is quite normal. My car sits pretty high and even higher when I have lifted it.

I haven't measured but suspect it drops an inch or so if driven a bit but not very much. Currently 4.5" between wheel and Arch on mine, had it in the air a couple of weeks ago and hasn't moved since.

I'd not worry about it, tighten it up and move on to next job. Once on the road you can loosen the suspension bolts once its had time and a few miles if you want.
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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PostPost by: Craven » Sun Apr 15, 2018 11:48 pm

I?ve had a situation where the shock absorber seem to freeze in the fully extended position, unfortunately with coil over?s it?s not easy to ? work ? the unit free. Have a feeling that if the shock has been lead down, the oil get in the wrong place.
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PostPost by: The Veg » Tue Nov 06, 2018 2:57 am

So almost seven months later I had a chance to revisit this. Tonight I attempted to fit the anti-roll bar but with the wishbones so far down below level, the mounts for the bar at the bottom of the dampers are now too close together by at least an inch. Guessing that if a little driving is going to theoretically settle the suspension, I should do it gently without the bar? Assuming of course that I get the car into operable condition one of these days.
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PostPost by: rgh0 » Wed Nov 07, 2018 9:34 am

The plus 2 front springs are highly stressed and normally settle faster and further than you will want with use. i would drive the car and see what happens. With a bit of effort you will be able to fit the roll bar even at full droop. Fit it to one side and get a winch or ratchet strap to pull it on on the other.

The various supplier don't seem to pay much attention to the detail of the original spring design so it would not surprise me if the springs were to long or to high a spring rate. Or maybe they know they sag so they make them longer or stiffer to compensate and reduce the number of returns they get for failures after a few months

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Last edited by rgh0 on Thu Nov 08, 2018 8:16 am, edited 1 time in total.
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PostPost by: jbeach » Wed Nov 07, 2018 4:29 pm

Veg,

I hate to say this, but it appears from your "before" photo your (extremely nice!) plus 2 was too high before you began this project. Continue to struggle with this if you like, but I'd just bit the bullet and purchase some fast road dampers with adjustable spring perches from TTR. Unless you have adjustable wishbones, ride height is the only way to affect camber and, the higher you go, the more your geometry will tend toward positive camber. While this is definitely true for the rear, I'm fairly certain it applies to the front as well. We all know positive camber is counterproductive to good handling.

Another comment - if you are going to drive around a bit to try and let your Elan settle (which I also recommend - it had a considerable settling effect with mine, when bouncing on the fender didn't), I would definitely do it with the anti-roll bar fitted. If you think about it, the anti-roll bar's pre-load will also subtly encourage your suspension to settle.

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-John
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PostPost by: jbeach » Wed Nov 07, 2018 9:05 pm

Veg,

My previous message sounds like I think I'm some kind of an "authority" on this subject. Please forgive me, because I am not. :shock: I have absorbed a good bit of information over the past 3 years and have learned a few things from the school of hard knocks, but I'm certain you (and most of the other folks in this community) know much more than I about the Elan. So, please take what I said with a grain of salt.

Best,

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PostPost by: The Veg » Wed Nov 07, 2018 10:37 pm

No worries John! Advice appreciated! It certainly sounds better than the other idea I had, to invite over a couple of my biggest, fattest friends to sit on the fenders while I try to fit the bar! :mrgreen:
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PostPost by: The Veg » Sat Nov 10, 2018 1:58 am

jbeach wrote:I hate to say this, but it appears from your "before" photo your (extremely nice!) plus 2 was too high before you began this project. Continue to struggle with this if you like, but I'd just bit the bullet and purchase some fast road dampers with adjustable spring perches from TTR.


After a quick bit of research looking at pictures of other Plus 2s I think you're right about it being a little high. At some unknown point in the past a PO fitted non-height-adjustable Konis all around, so I have no idea what went into them being made that height. The TTRs look like a good option; will give them a closer look. The lower height won't be a problem with my steep driveway either, as a friend proved with a V8 Esprit that had all of two inches of ground clearance and didn't scrape anything.
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