I changed from low to superlow springs about a fortnight ago. Everything has been fantastic until last night I noticed that whilst the rear right is sitting lovely and low (cant see top of tyre under most circumstances) the left rear sits a good 2 or 3 cm higher allowing you to not only see the top of the tyre but the spring and under body etc. What is the go? We made sure everything was seated correctly (well, I’m pretty sure we did). Could one of my shocks have died? You certainly can’t feel anything wrong with the shocks – yet there is a squelching noise in the rear that was there before we lowered it. There would not be that much of a weight differential between the two sides. I’ve since checked it out on a number of different surfaces to eliminate the possibility of unlevel ground. This is concerning!!!
How much would short traversal shocks lower the ride height? Presuming that a shock has died, it would be the right hand one wouldn’t it, considering it is now sitting lower? Can you get them tested cost-effectively?
Shocks do not determine the ride height, the springs do. Either the springs are mis-matched, not seated correctly, loaded differently (RHS heavier) or the car is twisted?
Just a thought, did you loosen all suspension links when you changed springs, only tightening them when the car was back at it's new ride height? Bushes can bind and be over-twisted, whether that's enough to hold the car higher I don't know.
Agree, the car's probably not twisted I just didn't want to rule that out - I'm sure you'd be noticing other problems if it was.
The suspension links should have been done up with the wieght back on the car though I am sceptical whether an over-extended bush would be able to support the weight of the car. More likely just lead to a rooted bush.
Shorter shocks (& struts) usually just mean a shorter overall shaft length. This is to prevent them bottoming out on compression on a lowered car and to limit the suspension droop on rebound so that shorter spring don't become unseated.
What you would need to lower the car more at the front with the same springs is a strut with a lowered or adjustable spring seat.
I may be getting confused here, this is as far as we got with the rear http://members.iinet.net.au/~scarecr...ck_removed.jpg We only undid the bolts at the top and bottom of the rear shocks, not the trailing arm or Watts linkage or anything like that. So naturally we did this up tightly before we took the stands out. Is this what you were referring to? What about a faulty spring that has sagged? I’d have to take them out / swap them over to determine this!
The point I am trying to make about rubber suspension bushes is that they have a very limited effective rotation from their fixed position. This is typically maybe only +/-10degrees of rotation - enough to reach full compression and full rebound from the static ride height. That's why it is impoartant to only tighten suspension links at the final ride height (vehicles weight fully taken by suspension).
Rubber suspension bushes typically have a central steel sleeve that the bush is bonded to, this is what the bolt usually passes through. Tightening the bolt to design torque will clamp the sleeve (and bonded rubber) and prevent it from rotating. The friction on the outside diameter of the bush where it has been press fit will prevent the outer diameter from rotating in the housing (they are not designed to slide in the housing). So with the inner & outer surfaces of the bush fixed the only relative movement that can occur is through flex of the rubber joint intself. This is how they are designed to work.
By leaving the suspension links fully tightened (or tightening them with the suspension at full droop) will cause the bushes to be over flexed by either removing the shock and allowing extra droop to get the spring out or having them fixed at full droop and then letting the car settle through the full range of it's suspension movement onto its springs. This will initiate micro-tears in the rubber and the bush will no longer be flexing but rather the two faces of these tears will be sliding over one another rapidly chewing out the bushes.
Sorry to be the bearer of bad news but that sounds like what you may have done. What I was suggesting earlier is that if the bushes had been fixed at full droop they may be exerting some leverage on the links, enough perhaps to increase the ride height marginally. Though I doubt this would be the case.
I'd be swapping the springs (left-to-right) to see if that makes any difference. You'll probably find the front springs being much stiffer may actually be causing this rather than the rears. Do one end at a time and see what the effect is.
Down the track you might want to get new bushes too.
Thanks RAPTOR. I'll inspect the work this weekend and see what I find. Just in case there is static tension there, I may loosen the bottom of the shocks, lower the car on the wheels and torque them again. Cheers!
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