Indy Shop replaced FCABs...

[jojodivo]

and now the steering wanders all over the place. They said the front control arm bushings were torn so I had them replaced with some power flex ones, but just as soon as I get the car back and get the speeds above 45 the steering jerks back and forth; much more noticeable in sport mode. It also seems to wander less under load as apposed to just coasting. The car had no jerking symptoms before the replacement and I just don't see how replacing them could cause the car to drive worse. Is it just a case of them replacing the FCABs and not doing a front end alignment or could something really be messed up, not reinstalled properly or worse broken? Any insight would be greatly appreciated before I go back to the shop on Monday.

[thekurgan]

Alignment sounds appropriate.

[wildag]

You need an alignment.

[AWM3]

It's also possible they installed the wrong bushings. They are not all identical.

[O-cha]

OP, can you give a few more details on the steering wheel "wander" saying that really says nothing.

Originally Posted by thekurgan

Alignment sounds appropriate.

Originally Posted by wildag

You need an alignment.

An alignment is NOT necessary when replacing the FCABs.

Fcabs only allow for changes in caster and are not adjustable at all, there is nothing to align.


Also if you can get underneath and take some pictures, they are in the wheel area, see here http://www.realoem.com/bmw/showparts...42&hg=31&fg=05

[wildag]

Originally Posted by O-cha

An alignment is NOT necessary when replacing the FCABs.

Fcabs only allow for changes in caster and are not adjustable at all, there is nothing to align.

An alignment is necessary, because he previously had stock bushings and now has the power flex urethane bushings. While there is no adjustability, they certainly change the alignment compared to a torn stock set.

[O-cha]

Originally Posted by wildag

An alignment is necessary, because he previously had stock bushings and now has the power flex urethane bushings. While there is no adjustability, they certainly change the alignment compared to a torn stock set.

You don't understand the geometry of the arm if you say this. A torn set might allow for inappropriate changes in caster under braking load, but the alignment remains the same despite them being torn, when the car is neutral and the arms are centered the alignment is correct. Correct the problem and you correct the caster under load as well, which is only far off during braking anyway.

It's not like changing a tie rod or RTABs where there's adjustment and it can't be put back together perfectly.


If you need anymore proof feel free to look at BMWs repair instructions which don't call for an alignment, only for replacement in pairs (for obvious reasons), and they call for alignment on tons of stuff where it's really not necessary, so if it was at all they would say to, and being powerflex has nothign to do with it either, they are centered bushings and the tolerances aren't far off enough.

Not to mention that having caster off does not cause steering wheel shimmy.

Most likely the shop did something strange, possibly took the control arm off or some other dumb unnecessary thing.

[jojodivo]

O-cha, the steering feels like this and only happens once the car is 65+:

the steering wheel will twitch a quarter to a half of an inch off center, I do not have to correct the wheel as the deflection is only momentary and then the steering wheel will twitch the same distance to the right. The deflections are not consistent and happen randomly, sometimes in a sequence LRLRLLRLRR... etc. or just once or twice LR or R. It does not seem the issue is road dependent, that is the behavior occurs on very smooth surfaces.

I hope this helps, as I was under the same impression that replacing the FCABs should not require an alignment. I will take pics this morning and post them. Thanks you guys for the input, it really bugs me when "expert" people present work that is not 100% correct.

[thekurgan]

Originally Posted by jojodivo

O-cha, the steering feels like this and only happens once the car is 65+:

the steering wheel will twitch a quarter to a half of an inch off center, I do not have to correct the wheel as the deflection is only momentary and then the steering wheel will twitch the same distance to the right. The deflections are not consistent and happen randomly, sometimes in a sequence LRLRLLRLRR... etc. or just once or twice LR or R. It does not seem the issue is road dependent, that is the behavior occurs on very smooth surfaces.

I hope this helps, as I was under the same impression that replacing the FCABs should not require an alignment. I will take pics this morning and post them. Thanks you guys for the input, it really bugs me when "expert" people present work that is not 100% correct.

Is it possible the new FCABs fixed the old worn slop that was present, and now you are experiencing a plain old "out of balance" situation with regard to the tires/wheels?

[jojodivo]

After looking under the car, this is what I found:

1) FCABs look good, they seem to have done a good job on them.
2) all suspension elements on the left side seem to be stable and do not give when attempting to move them (including trying to twist tie rod).
3) all suspension elements on the right side seem to be stable except the tie rod rotates easily in both directions when twisted.

I am sure it should be replaced, but is this the cause of the steering irregularities? I took a video of this and can post if needed.

[O-cha]

Originally Posted by jojodivo

After looking under the car, this is what I found:

1) FCABs look good, they seem to have done a good job on them.
2) all suspension elements on the left side seem to be stable and do not give when attempting to move them (including trying to twist tie rod).
3) all suspension elements on the right side seem to be stable except the tie rod rotates easily in both directions when twisted.

I am sure it should be replaced, but is this the cause of the steering irregularities? I took a video of this and can post if needed.

Really need pictures, need to know the color orientation and design, also try and take detailed pictures of the two mounting bolts, it's very hard to get them in place when they are first installed and they can be tightened in crooked despite there being locating sleeves, also check the bolts for tightness.


Did they do anything else to your car while you had it in there?

[XMetal]

These bushings should be tighten while the car is on it's weight (car on the ground), right?

[O-cha]

No, thats the rear control arms, and in essence RTABS but that's done in the air taking exact measurements instead.

[jojodivo]

I took pics of the bushings and of the tie rods. Here are the picks:

[jojodivo]

also, they did not do any other suspension work, I had a leaky #2 injector which they fixed and as far as I can tell it was done correctly.

[jojodivo]

After further inspection, it seems that the play in the tie rods is normal and is present on both. I also check the tightness of the bolts on the bushing housing and they were tight. I guess we will find out monday, thanks for the opinions guys.

[Blind32]

When did you get an alignment last? If its been more than a year, get one and see if that remedies it. If not, then oh well, you needed it anyways.

[inTgr8r]

I thought our FCABS were offset design?
Those look centered.

[jojodivo]

I had an alignment about 3-4 months ago when I had new tires put on. I am really at a loss, I expected the handling to be tighter and great due to the upgrading bushings. I really can't wait to hear the diagnosis; I mean how can the handling be worse with the bushing?

[jojodivo]

inTgr8r, can you elaborate on what you mean?

[Serious]

Those are the old style powerflex bushings... you need to get those out ASAP.

the problem is that the center bushing (completely different design from stock) can actually pull out of the outer bushing causing the control arm to fall out of the mounting location.

The proper new design powerflex bushings are black inner sleeves with black outer sleeves. Feel free to call bimmerworld for clarification.

[jojodivo]

Serious, I appreciate the lead, but when I went to the Bimmerworld website but they seem to be selling the bushings I currently have on my car. Your comments worry me as I am sure it would be very bad to have the control arm pull out of the bushing! Can anyone help to clear this issue up?? I have not called them yet but I will on my lunch break.