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Diagnosing a bent control arm?

Posted: Thu May 22, 2008 9:14 pm
by SKYHI
Hey guys,

I suspect I may have a bent lower control arm on the rear passengers side of my car. First clue was that I am struggling to get any decent rear camber on that side and second clue is that I needed quite a different setup on the tein flex coilover to achieve similiar ride height and droop measurments to the right hand side.

A couple of questions, who is best to diagnose and fix this issue, a wheel aligner? Secondly, as I have just put a set of offset control arm bushes in, are these going to be reusable or am I going to need another set?

Paul.

Posted: Thu May 22, 2008 9:24 pm
by JBT
Try Fulcrum for the geometry diagnosis and advice regarding the bushes.

Re:

Posted: Thu May 22, 2008 11:02 pm
by SKYHI
JBT wrote:Try Fulcrum for the geometry diagnosis and advice regarding the bushes.


Thanks, but Fulcrum haven't been much help to date.

Paul.

Posted: Fri May 23, 2008 6:20 am
by JBT
That's odd. In what way haven't they been of much help?

Posted: Fri May 23, 2008 8:27 am
by StanTheMan
Is one of the offset bushes spinning internally?

someone on here had mega issues with that sort of thing when we had this massive group buy a while back.

I have the offset bushes. But didn't have tose issues

Re:

Posted: Fri May 23, 2008 9:27 am
by SKYHI
JBT wrote:That's odd. In what way haven't they been of much help?


Fulcrum actually installed the bushes but only after a lot of hassle. Since then they've had two attempts at the wheel alignment and both times I have left clear instructions regarding the settings. However, when they haven't been able to achieve the settings I requested, they just make their own decision on what's best rather than consulting me first.

Both times the left rear has been well short of what I asked for and about 3/4 of degree different to the right side. Rather than ask themseleves why, they've just told me "that it's maxed out, and it's all we can get".

Paul.

Posted: Fri May 23, 2008 9:46 am
by JBT
That's disappointing.

I'm surprised that a bent control arm wouldn't be picked up. Is it actually bent or is the frame bent from an accident?

Re:

Posted: Fri May 23, 2008 10:05 am
by SKYHI
JBT wrote:That's disappointing.

I'm surprised that a bent control arm wouldn't be picked up. Is it actually bent or is the frame bent from an accident?


I had a good look at the arm last night and I can't see where it's taken any sort of hit and it doesn't look bent to the naked eye but obviously I can't be sure.

I just spoke to the manager at Fulcrum and he said they looked at the arm yesterday but couldn't see anything either but obviously they didn't look any further into it. He suggested it could be a slightly bent crossmember but at this stage I just need to find the best way to actually diagnose the issue so I can rectify it.

Paul.

Posted: Fri May 23, 2008 10:42 am
by JBT
I guess all that can be done now is to carefully check the cross member for evidence of damage or repair.

Are you sure the offset bushes haven't spun?

Re:

Posted: Fri May 23, 2008 10:49 am
by SKYHI
JBT wrote:I guess all that can be done now is to carefully check the cross member for evidence of damage or repair.

Are you sure the offset bushes haven't spun?


Thanks I'll have a thorough look under the car to see if there's is anything obvious.

I'm not sure that there isn't an issue with the bush, but the fact that I also had to adjust the coilover quite a bit from the recommended specs when it was installed, tends to make me think it's more than just the position of the bush.

Paul.

Posted: Fri May 23, 2008 11:04 am
by JBT
I'd be carefully checking around and between the lower arm mounts. It'd be good if you could compare measurements with a known good one.

Image

Posted: Fri May 23, 2008 11:06 am
by SKYHI
Thanks JBT.

So the only two parts that could be causing this issue would be either the control arm or crossmember, is that right?

Paul.

Posted: Fri May 23, 2008 11:18 am
by JBT
Well, if the crossmember is bolted up into the car OK, there is probably less likelihood of damage to the upper mounts. I'd be suspecting/inspecting the lower mounts for damage or to see if the distance between them (see red arrow) is different to a known good one.

If the crossmember is OK, then I reckon there is a problem with an arm - upper or lower - and/or its bushes.

I don't know if NA and NB rear arms are the same. A wrong arm (if that's possible) may have been fitted at some stage.

The upright could be bent too I suppose.

It's going to require a lot of time in awkward positions.

Posted: Fri May 23, 2008 11:37 am
by bruce
Do you know the complete history of the car? Has it had any repairs in the area?

It really is a job for the professionals to check all that.

Posted: Fri May 23, 2008 11:48 am
by JBT
Sure, but if you have the time and place to be able to give it a good check over yourself to see if you can identify the problem, where's the harm?

All there is to these things are the arms, upright/knuckle and crossmember.