[LanDzia]

E90 330i 2006 (late 2005 build).

I've been having bump steer (steering on its own left or right when going through various road imperfections).
Put the car on the lift multiple times, inspected with my mechanic all front suspension parts ... Bottom & upper arms, tie rods are looking perfect. Absolutely 0 play, all joins with no cracks or anything.
I've replaced both upper control arms in the past as they were shot, done alignment with no success.

I'm in the dark. No clue what could be the issue.

My mechanic thinks it might be steering rack itself, although he isn't 100% sure.
Also, I do not have any other issues with steering (except its a bit heavy, but I think it's normal. Changed power steering reservoir and fluid recently).
Actually, at high speed (90+ miles/h) car isn't stable anymore. It feels like there's a little play. This is likely related.

Any ideas anyone? Any experiences?

[Hoody007]

What are your alignment settings?

[LanDzia]

Originally Posted by Hoody007

What are your alignment settings?

[Hoody007]

Hmmm. Those look good to me. What condition are your shocks in?

[LanDzia]

Originally Posted by Hoody007

Hmmm. Those look good to me. What condition are your shocks in?

Honestly I'm not 100% sure. My mechanic told me they're OK and no need to change, however I feel these are original ones.
You think they might have relation?

[AWD Addict]

That's a likely culprit. Those would be pretty old if they're still original.

[Hoody007]

Originally Posted by LanDzia

Honestly I'm not 100% sure. My mechanic told me they're OK and no need to change, however I feel these are original ones.
You think they might have relation?

I’ve had bump steer issues fixed with new shocks in the past. Another good way to tell is by looking at your bump stops. If they’re rotting/worn away, it’s a good indication that you’re due for new dampeners.

[The Nightman]

2006 model year with 95k mile dampers? You'll likely benefit from new struts and shocks

[LanDzia]

Originally Posted by The Nightman

2006 model year with 95k mile dampers? You'll likely benefit from new struts and shocks

I'm not sure as I haven't seen any receipt from previous owners for new ones.
I guess it's time to inspect it properly myself.

[LanDzia]

EDIT:
Replaced:
- Front wheels about 6 months ago (michelin pilot sport 4 zero pressure (run flats). Rears are same Bridgestone potenzas on about 4mm thread.
- Front & Rear Struts (Bilstein B4 M sport)
- Springs (Eibach Pro Kit)
- all associated parts when refreshing shocks (all mounts, bump stops etc. both ends)
- Inner & outer tie rods
- done four wheel alingment

Bumpsteer improved, however it's still there! What a bummer.
No other visible issue with any other suspention component.

What now? I feel like I've hit a wall.

[LanDzia]

Up

[e90yyc]

Man… I am in the EXACT same situation as you, as far as I can tell..

Biggest difference being I’m now on my third steering rack with no improvement. There’s a knocking sound from my steering wheel when moving it at idle that just doesn’t seem right, but the shop I took it to doesn’t think anything is wrong.

I’ve replaced steering shaft twice (both times Genuine), rack with used replacement, then remanufactured. I just can’t see how it could possibly be the rack in my case, but what do I know, ha.

Without making this needlessly long, I’ve replaced basically every part that could possibly cause an issue and yet the issue remains. Doesn’t feel stable at speed, and steers itself readily when the road isn’t perfect. Yet no components appear to be clearly failed (nor should they be at their age).

I have not replaced the steering column, but I have removed it to check for play and briefly swapped in a used replacement. No difference.

Something that is not intuitive or obvious has to be going on. I keep thinking that steering feel on centre just does not feel right, but am struggling to logic through what might be causing it. I’ve even checked out other peoples’ cars here in my city, but the challenge is that a simple test drive or poking around the engine bay doesn’t seem to be enough. (I don’t want to ask a stranger to let me bring tools to pull the airbox and check the steering shaft.)

New tires, alignments, etc… issue persists.

When I bench-tested the rack (both my original one which was probably perfectly fine, and the Bosch remanufactured) I noticed no play. The reman especially was nice and tight, and even the smallest movements at input translated into rack movement.

Let’s keep in touch. This one has been driving me nuts, and while I’m sorry to hear you’re experiencing it too, it’s nice to at least know there’s someone else out there!

[Cal122]

My 2006 with sport package had a little bit of wander, it got a lot better after I replaced the thrust arms. They didn't appear shot but probably worn out from age. It was definitely worth it along with having an alignment done.

The 2011 with xDrive I almost thought was a lost cause after I went through replacing all of the shocks, mounts and even springs with factory parts. Replacing those components along with the thrust arms made a huge improvement. I had an indy align the car after. However, the car just didn't feel planted at all on the highway, hitting a bump/imperfection on the highway the car would go left/right on its own. I felt defeated after all of that work and thought it was just the way the xDrives perform.

That car I had in the dealer for warranty work and they were running a special on alignments. When inspecting, they saw all the suspension parts were new so they test drove and said it's definitely not holding the road right. While doing the alignment, they noticed the suspension components weren't preloaded correctly, so they went ahead and did that along with the alignment where the car is weighed down properly according to spec. Whatever they did corrected all the issues and it drives so well now.

I really don't know if it's the alignment machine they use or what, but I'm considering having them perform one on my 2006 the next time they run a special.

[e90yyc]

Cal122 Thank you for sharing what worked!

I’m going to start revisiting things I’ve replaced, starting with struts/mounts, tension arms, etc. Something is not right—steering wheel jerks if I’m on an uneven road at slower speeds, and driving on packed snow is often terrifying because it feels like I’m constantly slipping—so I’m now inspired to put this to rest once and for all .

Thanks again!

[whyzee125]

I think you're sitting on your bumpstops. I don't like Eibach springs as they're too soft with shorter ones but you also sit on the bumpstops with OE ones. IMO, while it will be a little soft for a lowered, car, you're still better off running the e36 M3 front stops. I bet that solves it!

[Nando_e90]

Originally Posted by e90yyc

steering wheel jerks if I’m on an uneven road at slower speeds

On the same boat here 2006 330i. Have had bump steer since day one. All front suspension components replaced and multiple alignment. This video tells everything about it, I think is the same symptom you describe:

https://drive.google.com/file/d/1elV...ew?usp=sharing

Originally Posted by Cal122

While doing the alignment, they noticed the suspension components weren't preloaded correctly, so they went ahead and did that along with the alignment where the car is weighed down properly according to spec. Whatever they did corrected all the issues and it drives so well now.

I really don't know if it's the alignment machine they use or what, but I'm considering having them perform one on my 2006 the next time they run a special.

Thanks for sharing this. I also think it has to do with proper alignment. I've seen caster can cause bumpsteer but seems it can't be regulated in this cars.
Maybe in the dealership they have the correct machine for it?