What’s up with my suspension?

[Petahgreen]

Hi all,

Like many, I took my Zed out for a proper shake down run after weeks of max 20 min driving a week during lockdown.

Hadn’t done too much work on the car during lockdown other than replacing the rear ARB links and bushes.(a painful job without a lift!)

Whilst out, there seems to be a squeaking noise that’s started that wasn’t occurring during my lock down drives.

Looking at the car this evening there very much seems to be a lean to one side.



Today I took each wheel off in turn to check the links and bushes were all still good. and to check coils for cracks. Nothing is obviously broken.

The zed is March 06 E85 3.0si on Sport suspension(done 90k). Other than renewing the ARB drop links and bushes front and rear, the only change is I installed Bilstein B6’s on rear (approx 18 months ago) and the original dampers were shot(as you would expect)

Is it a case of one of the front dampers(originals I believe) has given up the ghost and not pushing back against the spring?

Replacement dampers (to B6’s) or springs and dampers whilst I’m at it?

 

[oldgitdave]

It definitely looks to be leaning slightly but I don't think the dampers can affect ride height unless partially seized maybe (if that's even possible :? ). Surely it's only the springs that can do this, assuming no body or chassis deformation?

 

[buzyg]

I would definitely check the spring s again. T'int right, t'int fair, t"int proper.

 

[ph001]

Have you checked the rear springs since you installed the new dampers 18 months ago? Oem springs are notorious for breaking (usually right at the end so tricky to spot).

 

[Petahgreen]

Thanks all. I’ve checked them yesterday but I’ll give them a further look this week. Do they usually crack at the lowest point? That’s where I was giving a good examine.

Any recommendations on springs for the sports suspension? Seems like it’ll be any easy-ish job once I buy a set of spring compressors?

 

[mjennings23]

You don't need any special tools for the rear, take the wheel off, undo the bolt at the bottom of the suspension strut and then you can push the hub down and pull the spring out. I tend to put 1 foot on the hub and press down while wriggling the spring out.

Compressors are needed on the front, and its a pig as the coils have very few rotations, means there isnt much for the compressors to grab onto.

 

[Wookster78]

Mine looked line this a few months back, front coil had totally snapped off at the bottom, looked normal on initial inspection but the bottom section had been lost somewhere on a drive and the coil had reseated so looked normal. I’d check the ends for any shearing.

 

[R60BBA]

BMWs do naturally sit lower on the offside than on the nearside however yours looks exacerbated.

I would imagine that is due to a snapped coil spring(s).

Squeaking is probably coming from worn lollipop bushes or RTABs.

 

[Petahgreen]

Thanks All- possibly I’ve not spotted the end of a coil which might be entirely missing.

Ill get it inspected again and report back.

 

[Petahgreen]

Still not convinced any cracks in any springs/coils. Gave them a thorough look, including wipe down.

Front coils look much older. Perhaps worth replacing those and the dampers?

 

[Wookster78]

Which picture of the front coils is the lower side, in the picture with the cleaned up coil the end normally seats in the rubber part at the bottom with the 90 on it, possibly that last little bit has snapped off and it’s reseated, do you have a better picture of the ends of both coils?

 

[griffnut]

From the photo's one spring looks a lot newer than the other - there appears to be corrosion on lower section of the dirty spring. Hence have both springs been changed?

If only one got changed at some point in the past, that would be your answer.

 

[Petahgreen]

Which picture of the front coils is the lower side, in the picture with the cleaned up coil the end normally seats in the rubber part at the bottom with the 90 on it, possibly that last little bit has snapped off and it’s reseated, do you have a better picture of the ends of both coils?

Thanks for your help! This is the front right coil (lower side in original pic of front of my zed) both looked similar.



Realised that I didn’t take a cleaned photo of the left side coil.

 

[Wookster78]

I must admit from your last photo it does not appear to have snapped as you can see the original paint on the end. Assume you looked at the top of the springs also, although they do normally snap off on the bottom. Your rear ones look ok to me so I don’t believe they are causing your issue. I had a ceased shock once on the front but the spring had also snapped so difficult to say if they both contributed to the lean on one side. If you push down on each front wing do they have similar resistance?

Further thought and a long shot but check the rubber bush at the top of your suspension from in the engine bay, the rubber can crack a perish over time, slim possibility but could have perished enough to drop one side down.

 

[enuff_zed]

Maybe, as suggested already, the front springs aren't a matched pair? Although can't see how that would suddenly manifest itself if you hadn't noticed a difference before?

 

[ben g]

It definitely looks to be leaning slightly but I don't think the dampers can affect ride height unless partially seized maybe (if that's even possible :? ). Surely it's only the springs that can do this, assuming no body or chassis deformation?

When one of my front shocks failed, the ride height dropped about 20mm on that corner.

 

[Ewazix]

Just to give you a benchmark to work from these are the ride heights per TIS. When they leave the factory there is no difference in parts or settings left/right, most cars end up a bit lop-sided due to driver weight N/S, parking on kerbs N/S or wear/damage, but it's NOT a design feature (despite the urban myth that they are set up that way for fat LHD users :wink: ) .

There is a 10mm permitted tolerance from standard in the height, and a 10mm permitted difference L/R. Before measuring make sure you have at least half tank and sit in both sides of the car before measuring to compress both sides, measure on a flat surface having checked all tyres are correct, this wont affect the ride measurement (see diagram) but will affect the visual tilt.

If there is a problem it's usually spring damage, one is older or not matched (it can be tricky to know what springs you have if they have already been altered from OEM), or don't forget the top mounts which can degrade and are often overlooked. So unless your car has bent suspension the or chassis damage that is about all that can affect ride height. You can get different thickness pads for the springs to sit on, but this will just be masking what the real issue is. They can be useful if you are thinking of regular track work to take account of circuits.



The below are for 3.0Si other models are in the TIS link if you go back.
Front. https://www.newtis.info/tisv2/a/en/e85-z4-3.0si-roa/repair-manuals/31-front-axle-front-suspension/31-10-front-axle-suspension/6weS7l5
Rear. https://www.newtis.info/tisv2/a/en/e85-z4-3.0si-roa/repair-manuals/33-rear-axle-rear-wheel-drive-guide/33-00-rear-axle-rear-wheel-drive-guide/62SB1uh

 

[Petahgreen]

Thanks All, starting to wonder the same about mismatched coils as well as top mounts.

Given the dampers are almost certainly shot to pieces- think I will replace the fronts with B6’s and also buy new strut mounts and coils too. It’ll be an expensive one as I’ll need to buy a coil compressor too.

I know nothing on manufactures of coils- what’s best for the sports suspension- suplex? There’s plenty of different sizes so a little worried about getting the wrong spec.

Any recommendation on strut mounts? I’ve used lemforder for my drop links.

 

[Wookster78]

Lemforder are good I have used them in my car, similar to OEM. If you are changing it all why not go with a set of coilovers, I did mine and it’s much easier to replace with a whole new assembly than try and wrestle with a spring compressor on the old and new springs as they really are a pig to change over.

 

[Petahgreen]

Thanks all for your replies- this is really really helpful!

Coil overs seem abit more than B6’s and Springs though, what’s the benefit? I was thinking to keep same as rears seemed wise?

There seems to be a lot of choices on springs. Anyone know which would be suitable?