Loose steering at high speeds and mismatched control arm

1653 Views 2 Replies 2 Participants Last post by yattmaster, Jul 12, 2021

yattmaster

Discussion Starter · Jun 30, 2021

1990 LS Coupe
I've been rebuilding my front end, got new tires first, then did the ball joints and tie rods. I got some lower control arms for when I did the ball joints and had one of the arms removed, and then realized it did not fit, the frame mounting bushing hole was too small and the sway bar end link mount on my car is a hole in the side of the control arm, but the part I bought had a flange sticking out, as do all the others I've seen online. I've yet to find a control arm that matches my car, even the Haynes manual I have shows the control arm I see online with a different style of sway bar end link.

Either way, the control arm bushings seemed to be in decent shape so I reinstalled it on one side and didn't touch it on the other. After the ball joint installation, I noticed my steering is very scary and loose at higher speeds, above 60 or so. If I turn sharply into another lane it will take a second to respond then lean into it more heavily than I intended, then swing back sometimes. Moving the wheel back and forth quickly a few degrees doesn't steer the car immediately, but a small input will make it drift eventually. I've dealt with worn rack bushings before and its a similar feeling, this is different but hard to explain. Before I replaced everything it drove very sharp and straight as an arrow besides the clunks from the ball joints.

At a standstill the wheels turn with even the slightest steering wheel input, I can shake and lean on the whole assembly and nothing moves. The new tie rods even helped a little bit but its still dramatically worse than before I started all this work.

It's obviously due for an alignment, but I'd like to know if anyone has any pointers before I bring it in and they tell me it needs parts replaced, that potentially can't be sourced, and I still get charged for them basically telling me what needs to be done.

The three scenarios I can think of are this: 1. Just needs an alignment that's all, 2. I messed something up with the control arm or knuckle when I removed them, 3. my already whining steering rack got overstressed from the friction of the new ball joints and got loose somehow.

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paulo57509

· #2 · Jul 5, 2021

1. The sway bar attachment you describe on the lower arm (with a hole and not the flange) is like that on my '87 coupe. IIRC, the flange arrangement is on the sedans.

2. Did you change the locations of the radius rod adjustment nuts at (No. 2)?

3. Typically, before final torquing tightening the fastener at the lower arm pivot (No. 1), you do this with the weight of the car on the suspension. You want the bushing to not have any twist in the rubber with the suspension at normal ride height.

There are only two alignment adjustments for the front end - caster and toe. Camber can only be measured. If it's out of spec, something is worn or bent. Anytime you do front end work or parts replacement, the alignment should be checked and adjusted. You should have a 4-wheel alignment done.

The rear suspension is adjustable for toe, camber like the front is measured but not adjustable.

It would be worth the time and money to have them align or tell you what wrong. At least you won't be questioning what's wrong and you won't have to keep throwing whatever parts are still available, at it.

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yattmaster

Discussion Starter · #3 · Jul 12, 2021 (Edited)

paulo57509 said:
1. The sway bar attachment you describe on the lower arm (with a hole and not the flange) is like that on my '87 coupe. IIRC, the flange arrangement is on the sedans.

Thanks for the clarification, its hard to find info on these cars. Strange that I can't find the right part though.

paulo57509 said:
2. Did you change the locations of the radius rod adjustment nuts at (No. 2)?

I don't think I did. I only removed the necessary (2) bolts on the rear end of the radius rod to replace the control arm, then when I realized the new arm wouldn't fit I just put the old one back in place, the entire control arm was removed but everything else was still hanging from the car. Didn't adjust anything on the radius rod shaft or up by the bumper.
I also can't see an image if you tried to post one, though I think I know what you're talking about.

paulo57509 said:
3. Typically, before final torquing tightening the fastener at the lower arm pivot (No. 1), you do this with the weight of the car on the suspension. You want the bushing to not have any twist in the rubber with the suspension at normal ride height.

I made sure to do that.

paulo57509 said:
There are only two alignment adjustments for the front end - caster and toe. Camber can only be measured. If it's out of spec, something is worn or bent. Anytime you do front end work or parts replacement, the alignment should be checked and adjusted. You should have a 4-wheel alignment done.

That's good to know. I'm pretty handy but alignment is new to me, I've never worked in a shop or anything, I learn everything on youtube.

paulo57509 said:
The rear suspension is adjustable for toe, camber like the front is measured but not adjustable.

It would be worth the time and money to have them align or tell you what wrong. At least you won't be questioning what's wrong and you won't have to keep throwing whatever parts are still available, at it.

This is the plan I had unless there was some known Legend trick someone was aware of. I'll bring it in this week and report back.
I just got an email about this post or I would have posted sooner.

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