Please help:

I have been dealing with a very frustrating intermittent front end shimmy for a long time now. Last straw was this week when I put new tires on car and I still had shimmy. I have replaced struts, sturt rod bushings, lower ball joints and I had the front end aligned. Please help or I will literally kill my brick. I am that frustrated with it.

Thanks

Bearings?

Bearings?

Mark:

Could be. How do I check them?

I agree with chris and raidman, check the rims to see if they are warped. most (all?) of the rims on the 700s are aluminum composites. this means two things:

1) when and if they are bent they often split or break... I have one in my garage that split between two spokes when I went through a pothole. So damned annoying.

2) they can warp fairly easily if the nuts are tightened down unevenly.

take the car back to the tire shop and have them attempt to balance the new tires on the rims. if the rims are warped balancing will be impossible. you can then either buy a new rim to replace any warped ones, or go to a metal shop that can straighten it (ys, as hard as it is to believe, aluminum rims can be straightened by dudes that know how). if you choose the latter ask the chief tire guy at the shop if he knows a place in the neighborhood... he will almost assuredly have a place he uses.

on a sidenote, there is a solution that doesn't involve any of the aformentioned. I have two warped rims on my 1985 745t right now and have no shimmy. the trick is to rotate the warped rims to the rear and make sure you have two good rims upfront. the two in the rear will still be warped, but you won't notice it at all (sine it isn't affecting the steering tires). cheapo work around for those of us not excited by the propsect of purchasing new rims at $300+ a pop.

good luck,
rick

Rick:

Thanks for the input. I have the Hydra (put on the car by the previous owner)wheels on my brick so the warping thing is a distinct possibility. I think the tire balance is okay. They were balanced at the tire shop when they were put on and the next day when I took the car to another shop to have the front end aligned I told them about the shimmy. They set the toe in (the caster and camber where fine) and checked the the tire balance again. It was fine. He did say that the tire shop did a single plane balance (balance weights only on the backside of the rim) which was not as good as a double plane balance. Also, the car had a similar shimmy with the old tires, although not as pronounced. The only thing non OEM on the front end is the radius\stay arm bushings. I replaced them a year ago with the IPD polyurethane ones. Could this be the cause? I replaced the lower ball joints with MOOG parts. This summer, I check the rotor run out with a friends dial indicator. It was withing specs at .002 thousandths of an inch. The shimmy begins to be noticable at 40 mph and increases in intesity with speed. The really weird thing is that occasionally while driving down the highway it goes away for a while and the car drives like a dream only to return a few minutes to few seconds later.

I am going to switch the front tires with the rear one side at a time to see if I can isolate an out of round or bent rim.

Thanks again

You should also check the rotors before youdecide to ditch the brick!

Check for bent wheels and be sure they balanced your tires right.If you're
in the DFW area we can help you .
ReySC
--
ReySC..'86 744 GLE ..'94 944 T

ReySC:

I live in Taylor outside of Austin.

Hello Frus:
I'm in Texas, too...have the wheel bearings checked out...they were toast on my wife's 89 740. Drives like it is on rails now.
There are two different types...check the archives.
Hasta luego, Genaro.

Radius rod bushings, bent wheels (common) and a sticking brake caliper slide can all cause that as well. Often tire shops don't check for bent rims when they mount new tires, but it's entirely possible.
--
chris herbst, five volvos.