OK I swear I posted this yesterday but can't find it. Sorry if it's a repeat.

Daughter's '05 MCS. Hit a curb in the winter, slightly bent subframe, which was replaced. Alignment shop said couldn't quite get the camber spec, but close, shouldn't be an issue. However, no there is a loose/twitchy feeling to the steering, seems to be the driver front that got hit. Just feels unstable. The faster you are going the more you notice it. Can be going straight and will get a quick little wobble. Also feels funny cornering, again like the wheel is unstable. All ball joints, tie rods, etc. are good and solid. Thought it must be a bad CV joint so I replaced the axle, but no help. I'm left with nothing but the steering rack to wonder about, but I'm no ace mechanic (although I've been messing with BMWs for quite a few years so I'm not quite a hack either). Any advice? Diagnostics to try to nail down a steering issue? No obvious leaks or anything.

TIA

Chris Baker

 

Could be to lower arm bushing. With the tire pointing straight kick the front of the tire towards the back of the car. If you see the tire wobble as it movement forward an aft. This means the lower control arm bushing bad.
check video out
https://youtu.be/JtElI_WknGs

 

 

Have you had that wheel checked for straightness? Hitting a curb can make it impossible to balance.

 

Just a thought -
Did they happen to check, fix/flatten the strut tower mount for "mushrooming".
I had experienced unusual "skating" effect after hitting railroad tracks pretty hard. Everything checked out - until I noticed the top right strut tower mount was severely mushroomed.
Pounded it back flat and had it re-aligned. Seemed to solve my issues.

 

I had very similar symptoms - a little straight-line wander or looseness on-center, very slight but very disconcerting, and much more pronounced at highway speeds. Finally traced it down to a combination of carbon buildup in the steering pump motor and a failing lower u-joint on the steering column. Neither was hard to fix. Is it possible that this just happened to coincide with the suspension damage and isn't related? One easy test for the u-joint issue is if you feel unusual play or looseness in the steering with the car parked and engine off....but this probably wouldn't be perceptible when cornering. The carbon buildup issue made for random variations in the steering effort, very minor at first but progressing pretty rapidly over a few weeks. If it feels weird when you spin the wheel while parked with the engine running, that might be the culprit (or one of them).

 

This may be a silly question BUT was the rim replaced she hit the curb with or checked for balance ? If it's that rim I would bet it's bent or that side lower control arm got tweaked .
but if she hit a curb and just the subframe replaced , did they replace any suspension or steering components along with it ? Because i can guarantee the control arm atleast is bent or the anti sway bar... those are the 2x things I tend to see go bad when curbs get kissed.

 

Thanks everyone. Sorry, been traveling and just now getting to the responses.

Swapped to other set of wheels/tires after the hit so wheels aren't the issue. I don't think it's a bent anything from the wobble. Car is aligned or I'd definitely be looking for severe toe-out.

I'll be checking out the tire-kicking test, mushroomed strut towers, and steering column u-joints for sure.

 

If something was loose, the alignment tech should have found it. If something is bent, its possible the alignment came into spec, but when you turn the steering wheel it goes out, but the alignment tech also should have seen this.

Sorry, but I don't think an internet forum will be able to find your issue without pictures of the suspension components. We will be throwing darts that board, at best. My suggestion is to take it to a Mini specialist and have them examine the front suspension components.

 

If the subframe is not quite squared, possibly be effecting castor, effectively putting negative castor one side and positive on the other if its twisted. I have had my subframe off a few times and not noticed any issues after myself but I have heard there supposed to be fitted with a jig. Castor is not normally checked with normal alignment so would not be picked up.

Long shot but worth thinking about