Replacing Broken Rear Coil Spring

[maliceM3]

I preventatively replaced a rusting rear spring in my 2004 ZHP sedan. I ordered an OEM replacement through OEMbimmerparts along with a bunch of other stuff. Great prices and super fast shipping!

After I had all these parts installed, the driver's side is sitting abnormally high especially given it being the rear. Relative to the other side, it's noticeably higher. Now it is extremely cold in Chicago, so I haven't bother to examine this further but I wanted to clarify a few things after much searching.

1. I replaced a single rear coil spring. Am I learning now I should have replaced both?
2. Do spring really settle? I've heard mixed thoughts on this.

This isn't a major concern. It seems my car is eating oil a bit faster than it should, though I don't drive it very often. CCV next :facepalm

[ryankokesh]

I preventatively replaced a rusting rear spring in my 2004 ZHP sedan. I ordered an OEM replacement through OEMbimmerparts along with a bunch of other stuff. Great prices and super fast shipping!

After I had all these parts installed, the driver's side is sitting abnormally high especially given it being the rear. Relative to the other side, it's noticeably higher. Now it is extremely cold in Chicago, so I haven't bother to examine this further but I wanted to clarify a few things after much searching.

1. I replaced a single rear coil spring. Am I learning now I should have replaced both?
2. Do spring really settle? I've heard mixed thoughts on this.

This isn't a major concern. It seems my car is eating oil a bit faster than it should, though I don't drive it very often. CCV next :facepalm

1. Generally anything with suspension, do both sides at a time. Springs maybe I dunno ehhh... I would just do both.
2. I've heard both ways too. Latest I've heard is that the better springs will settle less. Seems like the general consensus is to give it a little time to get used to being 'sprung'.

CCV isn't as bad as it sounds...I think it's over-hyped a little. Just takes some time. :dunno

[LivesNearCostco]

MaliceM3,
I haven't seen your springs or car, but assuming you replaced only the driver's side rear coil spring, here are some theoretical possibilities.

New driver's side spring needs to settle
Passenger side spring is sagging from age or has broken coil at the bottom that you didn't notice it.
You replaced spring pads on driver's side but not passenger side, and new spring pads are thicker than old ones, either by design or due to age.
Forgot to reinstall one or both spring pads on passenger side?
BMW designed car to sit 1/8" to 1/4" higher on driver's side to account for solo driver weight (not sure if true)
You got the wrong replacement spring, since several springs were made for the E46. Do the color stripes match?



It could be a combination of things: 3mm from new spring not settled, 5mm from new spring pads, 3mm sag in old passenger side spring, 3mm ride height difference designed into car = 19mm = 3/4" height difference in rear.

[maliceM3]

Thanks LNC.

I'm not sure which of the issues it is, but after looking at some pics of well maintained ZHPs on here and Enthusiast Auto... I might as well replaced the other. However, now I don't know if I should replace all 4 with an aftermarket setup - I'm not looking for a drop, just comfort. Going to search around and see what others have done.