Bizarre Steering Alignment

[ph1l1p]

Good evening everyone,

I have recently been having some trouble with my steering / suspension and I was hoping someone would be able to give some insights.

Essentially, the issue I am having is that if I were to accelerate hard out of a left-hand bend on a junction or hit a pothole on my left wheel, my steering wheel will begin turned about 45 degrees left whilst the car tracks perfectly straight. To complicate things, I have noticed, on occasion, it will fix itself for a little while, then it'll go askew again if I were to drive with some enthusiasm or hit a pothole.

Furthermore, I have recently noticed that the steering feels rather vague (I can turn it about 15 degrees either way back and fourth in quick succession without the car changing direction whatsoever), and the car seems to wander a little.

Things I have checked:

• steering rack bolts on subframe
• tie rods / track rods & bushings
• shocks & springs

After much arguing with AI, it has decided that it may be the front control arm bushings, which is supported by the fact that I seem to get a very slight steering shake under braking, although I have had that since I bought the car, long before the steering issues. I can't say that I have ever seen AI give me the correct answer with car troubles, so I am very skeptical about it.

I also wonder if my rear track rod ends are slightly haggard as the car seems to wonder (especially at the rear), though I can't be sure as I don't have enough experience.

Regardless, I would like to hear what you all think before I start spending weekends fitting various things to my car to no end.

Thanks in advance.

 

[Rsipad]

I'd be very surprised if it was FCAB related. I accidentally broke an FCAB during install, it clunked and the entire wheel assembly was able to slightly rotate independent of the other wheels when parked with a slight nudge. Under braking I could literally feel my whole front left wheel move forward.

Based on what you've already tried, I guess you could visually inspect the FCABs, but after that my next step would be to recalibrate the steering angle sensor with INPA and Tool32 to make sure that's not acting up or out of alignment. Mine did some funky stuff when it got misaligned.

 

[ph1l1p]

I'd be very surprised if it was FCAB related. I accidentally broke an FCAB during install, it clunked and the entire wheel assembly was able to slightly rotate independent of the other wheels when parked with a slight nudge. Under braking I could literally feel my whole front left wheel move forward.

Based on what you've already tried, I guess you could visually inspect the FCABs, but after that my next step would be to recalibrate the steering angle sensor with INPA and Tool32 to make sure that's not acting up or out of alignment. Mine did some funky stuff when it got misaligned.

Thanks. I'll give that a go in the morning, but it does feel mechanical rather than EPAS related. If it isn't the problem, do you have any other ideas?

 

[Rsipad]

Thanks. I'll give that a go in the morning, but it does feel mechanical rather than EPAS related. If it isn't the problem, do you have any other ideas?

Could check everything in the rear to make sure that's all good. I have never felt the symptoms of a shot RTAB, but have read its goes bad on the M and e46 M3 at around 70k miles. Not sure if the non-M suffers from the same premature wear.

 

[ph1l1p]

Could check everything in the rear to make sure that's all good. I have never felt the symptoms of a shot RTAB, but have read its goes bad on the M and e46 M3 at around 70k miles. Not sure if the non-M suffers from the same premature wear.

Okay, thanks. I did the SAS reset and it is still the same, and it also appears to be reading correctly. It doesn’t have the symptoms of sticky steering, so almost certainly mechanical / suspension related. I’ll check out the RTABs.

 

[Zedebee]

Just to be clear from your 2nd paragraph, aware you saying that the your steering week can be 45 degrees off while driving in a straight line sometimes, and at other times it can be dead centre?

If so there is something seriously wrong with your steering geometry. The tracking could be massively out, which means you have probably bent something (likely track rod) hitting a pothole. I’d also check basic things like the suspension top mount bolts, recheck for broken springs, check all suspension mating points for tight bolts, broken drop links (rears are only little and easily missed), and lastly bushes. It is unlikely that worn bushes would give you that degree of movement. Something sounds broken.

 

[ph1l1p]

Just to be clear from your 2nd paragraph, aware you saying that the your steering week can be 45 degrees off while driving in a straight line sometimes, and at other times it can be dead centre?

If so there is something seriously wrong with your steering geometry. The tracking could be massively out, which means you have probably bent something (likely track rod) hitting a pothole. I’d also check basic things like the suspension top mount bolts, recheck for broken springs, check all suspension mating points for tight bolts, broken drop links (rears are only little and easily missed), and lastly bushes. It is unlikely that worn bushes would give you that degree of movement. Something sounds broken.

I appreciate the insight, but i’m not sure any of your suggestions would explain why it is sometimes off and sometimes straight. today it was about 15 degrees out when i left and pretty much straight once i got home.
I have checked top mount bolts and they all appear to be fine. Also, nothing appears to be bent. i noticed there was one deteriorated bushing (bushing for rear wheel carrier - connects to the end of the lower control arm on the rear offside.) Though, I agree that it seems somewhat unlikely for a bushing to cause this much movement.

 

[smorris_12]

I was pondering this on the way back from the shops yesterday and I had a thought. The amount of wrong is absolutely massive - 45 or 15 degrees - way more than a sloppy bush. I thought about what would be needed a bush to pull the front that wrong I reckon and you'd have to core the rubber out and just leave a bolt in there to get anywhere near. And you'd have found that.

And then it suddenly occurred to me - it's probably worn teeth on the pinion gear in the steering rack itself allowing it to jump along the rack by a tooth or two. This would explain it being out and then recovering later on, how you've not seen anything obvious and vagueness in the straight ahead position. It sounds like it's hanging on but something like the jolt from a pothole etc causes it to jump.

 

[ph1l1p]

I was pondering this on the way back from the shops yesterday and I had a thought. The amount of wrong is absolutely massive - 45 or 15 degrees - way more than a sloppy bush. I thought about what would be needed a bush to pull the front that wrong I reckon and you'd have to core the rubber out and just leave a bolt in there to get anywhere near. And you'd have found that.

And then it suddenly occurred to me - it's probably worn teeth on the pinion gear in the steering rack itself allowing it to jump along the rack by a tooth or two. This would explain it being out and then recovering later on, how you've not seen anything obvious and vagueness in the straight ahead position. It sounds like it's hanging on but something like the jolt from a pothole etc causes it to jump.

This absolutely sounds plausible. Thank you very much. Is there any way to prove or disprove this before trying to just replace the rack?

 

[smorris_12]

I suppose a starting point would be to jack it up, lock off the steering wheel somehow (like they do when you go for tracking, or else get someone to hold it) and see how much play there is in the rack by pulling and pushing at a wheel. You might not get it to jump but any play should be obvious.

 

[ph1l1p]

I suppose a starting point would be to jack it up, lock off the steering wheel somehow (like they do when you go for tracking, or else get someone to hold it) and see how much play there is in the rack by pulling and pushing at a wheel. You might not get it to jump but any play should be obvious.

Makes sense - I’ll try that. Thanks.

 

[Pumchdrunked]

I was pondering this on the way back from the shops yesterday and I had a thought. The amount of wrong is absolutely massive - 45 or 15 degrees - way more than a sloppy bush. I thought about what would be needed a bush to pull the front that wrong I reckon and you'd have to core the rubber out and just leave a bolt in there to get anywhere near. And you'd have found that.

And then it suddenly occurred to me - it's probably worn teeth on the pinion gear in the steering rack itself allowing it to jump along the rack by a tooth or two. This would explain it being out and then recovering later on, how you've not seen anything obvious and vagueness in the straight ahead position. It sounds like it's hanging on but something like the jolt from a pothole etc causes it to jump.

I think you're on to something here.

The only thing I'd say is, how come the steering angle sensor is not all over the issue? I'm surprised it hasn't disabled the TC, ABS, etc.

If it were me, I'd plug it into INPA and look at what's going on with the data.

 

[ph1l1p]

I think you're on to something here.

The only thing I'd say is, how come the steering angle sensor is not all over the issue? I'm surprised it hasn't disabled the TC, ABS, etc.

If it were me, I'd plug it into INPA and look at what's going on with the data.

Yeah, that is peculiar. I did check for codes and checked the live data when i had INPA connected at the weekend, but it yielded no results. The SAS is reading perfectly but it doesn’t seem aware of the issue.
I figure, it doesn’t always pick up issues if the steering is askew due to it needing an alignment, so it sort of makes sense that it doesn’t with this issue.

 

[bigwinn]

Yeah, that is peculiar. I did check for codes and checked the live data when i had INPA connected at the weekend, but it yielded no results. The SAS is reading perfectly but it doesn’t seem aware of the issue.
I figure, it doesn’t always pick up issues if the steering is askew due to it needing an alignment, so it sort of makes sense that it doesn’t with this issue.

It should throw a DSC code- the inputs won’t match forward motion with 45° input on the wheel- I’ve had it throw codes with poor alignment so that sort of deflection will absolutely make it trigger

 

[ph1l1p]

It should throw a DSC code- the inputs won’t match forward motion with 45° input on the wheel- I’ve had it throw codes with poor alignment so that sort of deflection will absolutely make it trigger

Weird - it hasn’t. But, would that discredit the suggestion about it being the steering rack? Or, is it just an abnormality?

 

[bigwinn]

Not sure

But a deflection of 45° is very wrong regardless… I’d say unsafe as a minimum

As it’s physical I would get the front up and try to replicate the issue somehow to see what is the root cause. I have to say the rack/gear would be my go to

If you can get both rack gaiters off you can inspect the gear and maybe look for damage

 

[smorris_12]

I did ponder the SAS as I know it doesn't need to be hugely wrong to set it off. I upset mine moving the steering wheel back a single spline (someone had moved it on one.)

The only other thought I had was one of the clamp joints in the steering column but that would also have the same SAS problem.

The only point that wouldn't throw a light but give sloppiness would be between the steering wheel and the column - but I can't see how the splines would wear...