Sprint front ride height.....

PostPost by: mark030358 » Sat Jun 11, 2005 3:21 pm

Gents,
Been looking at the front suspension. The car has about 1/2" mode tyre to arch clearance on the passenger side (UK) than on the drivers side. and this is a little difficult to expalin but here goes:-

On inspection of the lower wish bones the drivers side appears to be more parallel to the ground whereas the passenger side wish bone seems to be pointing down as if there is not enough weight on the shocker/spring assembly to force the wishbones into the near parallel position as per the drivers side :?: .

All the shocks/springs (standard units), uprights and trunnions along with all bushes are new. The frame and body are square and undamaged having been measured and checked.

Any ideas as to what may cause this?

If the trunnions have not been screwed into the uprights far enough or too far could this cause the problem?

I thinking that only the spring load/rate determines the wishbone positions.

All help much appreciated.

cheers
Mark
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PostPost by: steveww » Sat Jun 11, 2005 3:58 pm

Try measuring from the point where the wishbone joins the chasis to the ground on each side. The body may not be on straight.

The suspension bushes should be tightened with the car at its normal ride height.
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PostPost by: M100 » Sun Jun 12, 2005 10:20 am

>thinking that only the spring load/rate determines the wishbone positions.

It does on a suspension with rod end / spherical jointed wishbones that can freely rotate.

The rubber suspension bushes do not (on most cars) act like that. On the Elan the outer metal sleeve is fixed to the wishbone the inner metal sleeve is clamped between the pivot pin on the chassis upright and the nut. The rubber connecting the inner and outer sleeves then has to be able to accomodate the twist in the bush that occurs as the wishbone moves up and down, twisting one way when the wheel moves into the wheel arch and twisting the other way as the wheel drops down towards the road.

Tighten the nut up with the suspension unloaded with the wheel hanging down and that rubber has to twist when the vehicle is back on the ground at what would be normal ride height.

In doing so the weight of the vehicle is counteracted by the ability of the rubber in the bush to twist, sometimes to the extent that the rubber cannot tolerate the twist in one direction so the vehicle settles at a higher static ride height than it would do with a freely pivoting suspension. This also means that when the wheel travels into the wheelarch on a bump the rubber can be overstressed and ultimately fail.

So as Steve said the suspension bush nuts should only be finally tightened to clamp the inner metal bush when the suspension is at normal ride height.
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PostPost by: mark030358 » Mon Jun 13, 2005 1:33 pm

Hmmm,
I did leave all the suspension bolts loose(ish) drove the car the tightened everything. Still high on passenger front corner. Both rears by the way are correct. Anyway stripped everything down and reassembles very carefully. Left bolts loose, went for a spin then tightened everything....STILL HIGH!

Measured fron top of tower to centre of shocker, results drivers side approx 34cm (13.4") and passenger side approx 35cm (13.8").

Does this sound likes shocks/springs to stiff??

Any other help well received.

Cheers
Mark
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PostPost by: M100 » Tue Jun 14, 2005 10:26 am

Are you sure the surface you have the car on is level?

Then again its 3/8 inch which is bugger all ;-)
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