Some funny wobble in my steering... Input??

[metalmonkey47]

Forgive my ignorance, this is my first time ever owning a rack & pinion car so I'd like to be thorough.

My '70 Z has a slight wobble in the steering from side to side about 1/4-1/2'' at low speeds. I haven't gotten it up past 20 mph yet, as I'm still doing some minor repair work before a hard shakedown run so I can't say how much better/worse it gets at different speeds.

I've had my hands on every piece in the front end, ball joints, tie rods, control arms, etc etc. The only issues I ran into were sway bar mount bushings, and a slight looseness in the rack mount bushings. Since then I have replaced all those bushings with MSA supplied bushings. I have not had a chance to test drive the car again since then but Just in the event the issue wasn't resolved from the bushings, is there anything you guys might be able to suggest as to what might be the cause of this? Again, I'm very new to working on rack & pinion cars....

This particular car is very clean and original, and happens to be pretty well maintained. I can't help but think there might be some damage done to the rack though.

EDIT: Left this out, I've put a wrench on every nut on the car and they're all super tight, so it's not a matter of any loose joints or loose nuts. Except the one behind the wheel.

[Mikes Z car]

That guy behind the wheel is the most important part of the car.

For a quick look I have have had someone wiggle the steering wheel back and forth while I lay under the front end looking for anything moving in some way it isn't supposed to.

[yakhopper]

Might take a closer look at the tires ;0)

[metalmonkey47]

That guy behind the wheel is the most important part of the car.

For a quick look I have have had someone wiggle the steering wheel back and forth while I lay under the front end looking for anything moving in some way it isn't supposed to.

The only apparent play was in the rack mount. But I will go back over it to be thorough. I wonder if the issue might be in one of the coupler's or the u-joint from the steering column shaft to rack input.

Might take a closer look at the tires ;0)

Actually, a good suggestion...they are rather old. I do have some spares I might toss on for ****s & giggles.

[EuroDat]

+1 on yakhoppers post. Does the frequency of the wobble increase with speed and then go away? It could be balance or a bad tyre. You could try swapping front to back and see if it improves and get the wheels balanced.

Has the car been standing for a long time with wheels on the ground. That can cause flat spots which can wobble the wheel at low speeds and vibrate at higher speed until the flat spot eventually goes away. Typical after a winter stop.

Chas

Edit: If your not used to racks, they tend to be more direct. One thing for sure, if anything is clunking or wobbling in the steering, you will feel it sooner in a rack & pinion car.

Edited May 3, 2014 by EuroDat

[SteveJ]

Matt,

Try to get Tim McGovern or Matt Isabel to look at it. They could probably give you a good first-hand assessment.

[metalmonkey47]

Hey guys thanks for the feedback, you guys put me on the right track for sure.

Steven, Tim is a little ways away from me and Matt is out of town, racing I think so I'm going to have a buddy look at it. Seems like it's got to be simple.

There's no play anywhere. I FINALLY got the car home tonight, and driving it was wonderful. It's so responsive and quick steering that I was kind of worried at first that something was loose. I got used to it quick. The car tracks straight and drives so well.

Getting it up to 50 was easy. The wobble is only to the left at low speeds. Once you get it above 15 the car is stable. Wondering if it might possibly be in the tires. I'm putting some new 185/65/14's on it in a week or so. We will see soon.

[EuroDat]

When you get the new tyres, tell the tyre shop about your vibration and ask them to check the wheels for runout on their balancing machine. Its a simple check to do and will eliminate the wheel as a source of your problem.

You didn't mention if you have alloy wheels. If you do have alloys, check the the wheel nuts don't have too much clearance around the shank of the nut. Too much clearance and you can tighten the wheel out of centre and cause vibrations. Although such a vibration will get worse with speed.

Good luck with it.

Chas

[metalmonkey47]

Thanks Chas, I'm getting tires tomorrow so I'll remember to mention that. I know the guys at the shop personally so I trust I'll get good advice.

I'm using some generic steel wheels with tapered seat nuts, so I don't imagine that could be the issue.

This wobble is only at very low speeds, but I do have a slight vibration at higher speeds, so either way it seems like I'll need tires/balancing. The tires are rather old and dry-rotting anyways.

I'll post back tomorrow. Thanks!

[metalmonkey47]

Well just a simple update, the new tires fixed it! The car rides so smooth it's actually quite nice.

Thanks everyone!

[jfa.series1]

Yaaayyy!!! Enjoy The Ride.

[Carl Beck]

Did not see this Post weeks ago..

For others that might read it in the future.

When the steering wheel moves side to side as first described - at low speeds; or when the rear of the car moves side to side at low speeds {aka Duck Walks} - it is often an indication of radial tires suffering from tread separation.

The easiest way to check - is to jack the front or rear of the car up - and spin the tires by hand - watching the center of the tire - as the treads roll by. If it is a tread separation - you'll see the treads wave side to side as the tire spins by - and often you will see a budge in the treads as well.

The tires may feel pretty smooth at higher speeds - but don't drive on them - as at higher speeds the tread can completely separate from the body of the tire.. and do a lot of damage to the sheet metal around the wheel openings.

FWIW,

Carl B.