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Discussion Starter #1
Bought my new to me S4s a month or so ago. This is my first Lotus in 15 years, but before that I owned two different Esprits for a long time, as well as buying/selling at least 20 of them in that same period. I know what an Esprit should handle like. My S4s is overall very good, but even thought it only has 12k miles, the suspension was very tired. Time eats rubber. We replaced the shocks/springs with the Bilstein/Eibach package. We replaced all the lower suspension bushings. Alignment has been done to almost zero tolerance. It is right on.

In spite of all that I am still getting a weird looseness in the suspension. I think its in the rear. If you make a very minor steering adjustment, you can shortly after feel the back end wag just a bit. The feeling is repeatable. Its more noticeable when making a steering adjustment in the middle of a turn, but you can feel it even on a straight at highway speeds. Its not the kind of thing you would lose control of a car, but the whole point in owning a Lotus is that the suspension is perfect. It was much worse before the other work was done, but I knew the shocks were shot so at that point I was not surprised. I have to figure this out.

We did not replace the rear control arm forward bushings because they seem very tight. Looseness there would certain yield the symptoms I am seeing. Is it possible they are loose but it doesn't show by trying to move the arms with a pry bar?

Everything is very tight. Wheel bearings, ball joints, tie rod ends, steering rack. Is there anything else, especially in the rear, that I should be looking at? Those control arm bushings are not a trivial job, so I'd like to rule out other possibilities first.
 

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The way you are describing the symptoms, I would guess that a previous owner installed a really stiff rear sway bar…or set it to the inner most (stiffest) setting if they are adjustable. You did not mention the tires…that could be the cause too. If you set the toe on the rear wheels to about 0.02 degrees, it will help significantly in the transition stage of your turns and make the car feel very stable going into and out of turns. What is your rear toe set at now?
 

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The way you are describing the symptoms, I would guess that a previous owner installed a really stiff rear sway bar…or set it to the inner most (stiffest) setting if they are adjustable. You did not mention the tires…that could be the cause too. If you set the toe on the rear wheels to about 0.02 degrees, it will help significantly in the transition stage of your turns and make the car feel very stable going into and out of turns. What is your rear toe set at now?
No! This is an Esprit, there is no rear sway bar!

To the OP, The suspension needs to be loose until the car is at ride height or else the bushings will be locked at the unladen height, and then twisted as the car is lowered back on the wheels. This can cause the bushings to be deformed or have a pre-load that can cause the handling to feel uneven or squirmy.

Re-loosen and then tighten while the car is level, then check alignment as well...
 

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Discussion Starter #5
Travis - that's a good thought, we did not do that. Bushings were installed and tightened with the suspension hanging. Easy to do, I'll try that before going further.
 

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Discussion Starter #6
Closing the loop on this one. Problem was that the rear suspension toe was improperly set by the previous shop, and I fell into the same trap. When we read the alignment, our readings were right on at 0.2 degrees negative. 0.2 degrees is exactly on-spec, so we looked elsewhere for the problem.

The rear suspension calls for 0.2 degrees toe IN. Those who do suspension work will see the mistake right away. Negative is toe OUT, not toe IN. Since it was exactly the right number on both sides, but in the wrong direction, it appears the previous shop got the positive/negative mixed up. Until now I followed their footsteps. We need 0.2 degrees positive toe, not negative.

You don't get exactly 0.2 degrees negative on both sides by accident. The previous shop used whole bunch of universal body shims to get that much toe out. Those body shims were outboard of the control arm bushing, where Lotus allows the use of up to three 1mm washers for final adjustment. Anything more needs to go inboard of the bushing, to reduce leverage and flexing. There was much more than the allowed amount, so I expected that replacing the too-thick ourboard shims, with more plates inboard of the bushing would eliminate the flex. I now have $100 of brand new toe adjusting plates that I don't need, because to move the toe IN, I removed not only the body shims, but also several of the shim plates inboard of the bushing.

As you can imagine, changing rear suspension from 0.2 degrees out, to 0.2 degrees in, is a big change. Now the car handles like an Esprit! Very stable, not at all twitchy.
 

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All of those shims should have been a big tip-off that something was way off without even measuring things. Any tech worth his salt will usually look things over before doing anything just so he has a general picture of what is going on. Not noticing way too many shims on BOTH SIDES is a big thing to miss. Heck, you should have been able to eyeball the rear tires and seen that! That and the wear on the rear tires! At least you got it fixed.
David Teitelbaum
 

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Interesting that the people in the alignment shop thought that was a good idea...

I had my 89SE aligned after replacing every suspension component and making my own adjustable upper links, and did not need any change for rear toe. I did watch the alignment guy like a hawk, and chose all my own settings.
 

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Interesting that the people in the alignment shop thought that was a good idea...

I had my 89SE aligned after replacing every suspension component and making my own adjustable upper links, and did not need any change for rear toe. I did watch the alignment guy like a hawk, and chose all my own settings.
I am not surprised at all. Alignments are one of the worst get-what-you-paid-for services in all of the automotive industry. So many of them cut corners, and alignment "specialists" are experts at giving excuses on why what they did wrong is right.

For alignments, I look for a shop that I can build a personal relationship and be in the shop watching while they do it.
 

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Finding an alignment shop that will take the time (for money) to locate the centerline of the car and "string align" the suspension at the correct ride height and to the Lotus specs is most difficult, but well worth it!
 
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