Need some help diagnosing a front end shimmy. Options

[KaptKaos]

My car is a fairly stock '73 1.7. Two years ago, I upgraded to turbo tie rods with bump steer spacers. A few weeks ago, I added a Tarret front sway bar and new rear springs.

Recently, I have noticed a slight shimmy in steering wheel. It varies with speed. It slowly seems to be getting worse. Yesterday, I rotated my tires front to back, to see if it was a wheel balance issue. The shimmy persists.

I have gotten advice that I should replace my bearings in the front. I do not know when they were replaced (if ever), so I am considering that as well.

I am looking for a set of procedures that will help me to isolate the problem(s). Ideally, a step-by-step process of things to check that will either identify or eliminate a component as the source of the problem. I don't want to just start replacing things until I find the problem, but I realize that sometimes, cheap replacements are just smart to do anyway (the aforementions bearings).

Thanks in advance for your help with this.

[DanT]

front shock going bad? (IMG:style_emoticons/default/sad.gif)

[drive-ability]

I'm sure there are a lot of guys who have had similar problems. I had it and still do just a bit. My front end is all new and I found the tire balance to help the most. Sure thats the reason you balance them but not all places balance them correctly or give a hoot. I see how you moved tires around but I did that as well and made the same assumption and was incorrect. My problem is 95% gone but I still think the tires aren't balanced correctly. I plain to have them balanced by someone who really has the correct equipment and knowledge. I did replace every part of the front end as part of my build having said this wheel bearings, ball joints, tires, and surely other things can cause the problem.

[KaptKaos]

So far, I have the following steps:

1) rebalance tires
2) check front shocks (best way to do this?)
3) Replace front bearings.

What next?

[Dr Evil]

torsion bars adjusted right? (IMG:style_emoticons/default/confused24.gif)

[SLITS]

Loosen lug bolts and retighten slowly to make sure wheel is centered on rotor..... ask Joe Sharp why.

[KaptKaos]

Loosen lug bolts and retighten slowly to make sure wheel is centered on rotor..... ask Joe Sharp why.

I thought of that too Ron. I rotated the tires and was very careful with how I put the wheels back on. With 4-lugs, (assuming lugs are North, South, East and West) I would tighten the top, then the bottom, then one side and then the other, and continue until all 4 lugs are tight.

torsion bars adjusted right?

Mike, I haven't touched them, but how could I check to see if they are adjusted correctly?

[Dr Evil]

Go to Joe Sharps and do a corner ballance (IMG:style_emoticons/default/biggrin.gif) Other than that, I do not know. I have chased this problem in every 914 that I have owned. I have heard that if one is tighter than the otehr it will cause a shimmy. Not sure how to adjust correctly other than eyeball. Someone with more experience with this will probably chime in.

[tommy914]

Balancing is the most likely culprit, especially if it varies with speed. Check to make sure you have hub centric rotors. My early 73 did not. Then get a really good balance job. Weights should be spread on the inside and out side of the wheel depending on the tire. If you don't like weights on the outside of the rim, use the sticky weights on the inside of the wheel, but they still should be spread toward to inside and outside.

Also, make sure there is no preload on that new sway bar.

Tommy

[KaptKaos]

Balancing is the most likely culprit, especially if it varies with speed. Check to make sure you have hub centric rotors. My early 73 did not. Then get a really good balance job. Weights should be spread on the inside and out side of the wheel depending on the tire. If you don't like weights on the outside of the rim, use the sticky weights on the inside of the wheel, but they still should be spread toward to inside and outside.

Also, make sure there is no preload on that new sway bar.

Tommy

Thanks Tommy. When I installed the sway, I adjusted for preload, so I think I am ok there. Could that change? I don't know how it would but is it possible?

Tires are first on the list. Anyone know a good shop in West LA to balance tires properly?

THanks,
Joe

[Dr Evil]

How do you preload a factory sway bar? What adjustments are there? I just attached mine and went.

[KaptKaos]

How do you preload a factory sway bar? What adjustments are there? I just attached mine and went.

Mine is adjustable. Its aftermarket. I don't think that the stock ones can be adjusted.

[tommy914]

Thanks Tommy. When I installed the sway, I adjusted for preload, so I think I am ok there. Could that change? I don't know how it would but is it possible?

Tires are first on the list. Anyone know a good shop in West LA to balance tires properly?

THanks,
Joe

Pre-load of the sway bar would only change if you adjusted the torsion bars/ride height or adjusted the sway bar itself.

Tommy

[Aaron Cox]

Joe...

check your wheel bearing play
check your BALL JOINTS.

jack the front up, and grab the wheel and try to "rock it"
if there is any play, your bearings could be slghtly loose, or you could need new ball joints. you gotta determine where the play is.....

ball joints original? bearings original? suspension bushings original?

[Toast]

Get your tires BALANCED.

Rotating them did not work for me either. I then had the wheels Balanced, and the shimmy went away.

[KaptKaos]

Joe...

check your wheel bearing play
check your BALL JOINTS.

jack the front up, and grab the wheel and try to "rock it"
if there is any play, your bearings could be slghtly loose, or you could need new ball joints. you gotta determine where the play is.....

ball joints original? bearings original? suspension bushings original?

Thanks AA,

This is the kind of stuff I am looking for. I want to take a good look at the car this weekend and see what I can find. I want to drive it to GAF, but if it doesn't improve, I will be drving something else (IMG:style_emoticons/default/sad.gif)

[Jasfsmith]

So far, I have the following steps:

1) rebalance tires
2) check front shocks (best way to do this?)
3) Replace front bearings.

What next?

Any chance that you've replaced pads recently? If so, check to see if you have a sticky brake piston with a slightly warped rotor.