rear suspension ?'s

[Frank Gallegos]

I suspect the previous owner swapped out some rear suspension components in the  91 318is I now have.  Is there any way of being able to tell if I have the correct trailing arms, rotors (rear hub assembly), and shocks on my car?

[monty23psk]

first, do you have 5 or 4 lug? If 4 then you have an e30 suspension. Whether its early or late e30, that will need some work to find out.  But at least that is a start.

[Frank Gallegos]

Monty, it is the e30.  The question is, is there any way by looking at what is on the car now would it be possible to tell what parts they are?  Would there be any kind of identifing marks to label the parts?

Thank you for taking the time.

Frank

[DesktopDave]

I doubt it.  Mine have no marks that I recall.  Just grease leaking from the outer joint. I'm not really sure why you're concerned...quality, theft, fraud? :eek:

Or are you one of the lucky ones with bright colored polyurethane or billet aluminum?  Post some pics so we can ID it for you.

Those rear arms last forever, no reason to suspect non-OEM.  The rubber bits like bushings & end links might be from anywhere.  I'd check 'em; replace what was worn; leave the rest alone.

[monty23psk]

To OP, like Dave said will be heard and is there a concern? Really the only thing that gets swapped out there if it was not for a 5-lug woudl be the springs and shocks. Everything else stays stock except for the bushings which can be upgraded. Sure parts could have been changed to aftermarket, but even that should be within OEM spec to a certain point. Other options would be swaybar and reinforcing the TAs for this. A weird upgrade would be to swap out the TA with a newer version to get a little bigger wheel bearing.

[Frank Gallegos]

The reason I am asking is because the car has a floating/jerking that happens from time to time in the rear end. Very dangerous during the icy months. The tires wear something fierce on the inside. Took it to get an alignment and the fellow, who is know for being pretty good, said he can not figure out why the alignment is off by 1/2inch on each rear tire. The dust shields also look like they do not match-close but still not the same. The small hinge that the e-brake line attaches to at the rear hub is also different from one side to the other.

[max123]

Strange symptoms, but the wayward/floating rear end is a typically cause by worn subframe bushings.  This could also cause alignment issues, but is doubtful.  Also, on the rear alignment, you are aware of course that there is no way to adjust or change the alignment on the rear wheels other than to install eccentric bushings in the trailing arm (part#33329058822).  It is also possible that someone tried to install the eccentric bushings in the past and made a hash of it, it is also possible that the car was hit, or smoked a curb in the past causing the rear end to go way out of spec.

In any event, I would highly doubt that the above can be fixed on your garage floor and needs to be done in a shop.  I had my rear end completely redone with new trailing arm and subframe bushings - it is a cow of a job and takes a good mechanic all day - budget $1k provided there is no damage to the subframe.

[max123]

Also, as a first check I assume you have looked at your differential bushing - no one ever seems to replace them even though it is fairly easy.

[Frank Gallegos]

Thank you for taking the time and all of your insight.

[d.hitchcock]

It sounds like your car has lowering springs.

Lowering the car changes the suspension geometry and increases negative camber at all four corners.

This effect can greatly enhance cornering, but can also cause uneven tire wear, with treadwear being greatest on the inner third of the tread.

So, to your original question, it sounds to me like your car has had aftermarket springs installed (it is so common as to be considered standard practice ... ), possibly with sport shocks.

And a big +1 for the floating feeling being caused by worn trailing arm and/or rear subframe bushings. Probably all of the above. It's a tough job and gets neglected.

d.hitchcock

[dsm2002]

The reason I am asking is because the car has a floating/jerking that happens from time to time in the rear end. Very dangerous during the icy months. The tires wear something fierce on the inside. Took it to get an alignment and the fellow, who is know for being pretty good, said he can not figure out why the alignment is off by 1/2inch on each rear tire. The dust shields also look like they do not match-close but still not the same. The small hinge that the e-brake line attaches to at the rear hub is also different from one side to the other.

Sounds like what has happening to my 318i. The problem for me is worn semi-trailing bushes and it being lowered without alignment, i.e. camber and toe, correction: soon to be fixed with new bushes and camber/toe plates.

I cannot help with mismatched dust shields/e-brake attachment, except to say that they'd be no difference in the alignment of any non-M3 e30 arm.

HTH