Rear off-side corner "sagging"

timjones1 · Post by **timjones1** » Mon 23 Aug, 2004 12:54

Looking at the rear of my 2.2i on Sunday I noticed that the right hand rear corner was about 1.5" lower than the left. I was parked on level ground with no load in the boot or cab. I could get three fingers between the wheel and the arch on one side and only one on the other. I saw this on two different level surfaces.

Looking at the car today, however, on a different level surface, I now see no difference...

The steering did feel a bit vague on Saturday night on the M25 with a bit of unexpected drift, and the rear wheel was making a lot of "stamping" noise, but I put all that down to possible cross-winds and the appalling M25 road surface.

I was thinking about a suspension problem, maybe the shocks, but then it all looks level again today.

Any ideas?

muffles · Post by **muffles** » Mon 23 Aug, 2004 14:26

if the shocks are the same i can't see how it would be them. i don't know much about actual shocks but i know the principles, so if you think about it they affect the speed of adjustment not the range/setting. it's the springs that affect where you eventually end up, not the shocks, which affect how quickly you get there.

alternatively, i hear gas shocks raise the car a little bit as they use compressed gas so you can see how they would do that. if one was broken maybe that would do it, but i would expect a consistent problem...actually, i'd expect a consistent problem anyway! this doesn't help but maybe it gives ideas to people

TonyCal · Post by **TonyCal** » Mon 23 Aug, 2004 15:17

Sounds like a broken rear spring to me rather than shocks. the springs control ride hieght not the shock absorbers.
Its probably just one coil broken near the top or bottom and depending how the spring sits after driving depends on the height.
Worth a check to see if it is. Jack the car up and remove the wheel it should be obvious if the spring is broken.

timjones1 · Post by **timjones1** » Mon 23 Aug, 2004 16:38

Thanks for the replies - I'll check the springs out.

Kiwi · Post by **Kiwi** » Mon 23 Aug, 2004 21:17

Can also be a bent rear trailing arm - but given you don't mention smashing into any curbs I guess that is not it.

A while after I had brought my Z I noticed that it sat about an inch lower on the rear driver side - turned out the trailing arm was bent and I had to have it replaced (too bad the BMW dealer didn't notice this problem at the pre-purchase inspection).

timjones1 · Post by **timjones1** » Tue 24 Aug, 2004 08:28

Well, no obvious sign of spring problems and it's still sitting level this morning.

I guess I'll have to go with the shock absorber theory. Now I just need it to fail again for long enough to convince a dealer to do the warranty work!

muffles · Post by **muffles** » Tue 24 Aug, 2004 08:51

what's the shock absorber theory? i thought we all just said it couldn't be them, hehe

it could also just be the way the car sits sometimes - have you ever jacked up one side of the car and noticed that when it is lowered back down that side is much higher? it's because of the way the wheel encounters (for lack of a better word!) the ground, pulling it in slightly.

i don't know how that could happen (easily) in normal use, but maybe...

timjones1 · Post by **timjones1** » Tue 24 Aug, 2004 10:33

FWIW, the shock absorber theory is:-

1) I know nothing about how car shock absorbers are made

2) However, some other kinds use a "dashpot" - piston in an oil filled cylinder with a restrictied route around/through the piston - see http://www.daikin.co.jp/chm/en/furoro/m ... a_12_1.gif for an example

3) Maybe the shock absorber went down, but was prevented from coming back up by trapped dirt/blocked channel/whatever and was therefore holding the suspension down.

4) Something gave it a jog and it's now free.

Well, you did ask...

(mind you, it sounds like grasping at straws to me too

)

muffles · Post by **muffles** » Tue 24 Aug, 2004 13:30

ah yup i believe that's how many car shock absorbers are made - the other way (gas) is fairly similar just no gap for anything to go through, i believe - it just pushes against some gas which prevents it from moving downwards much. not clued up on them though, i think a lot of aftermarket shocks are gas though.

i didn't consider them getting trapped really though! it is certainy possible i suppose, but maybe on something on the outside (the inside is completely sealed...).

what about spring binding? i heard they (the coils) can stick together like that, i think due to rust

timjones1 · Post by **timjones1** » Wed 25 Aug, 2004 07:51

No rust on the springs (only two and a half years old). Still sitting level today

so I think I'll just have to wait and see if it happens again!

Thanks for all your help.