vibration from front end
 

My 86 na has always handled well with no vibration in the steering wheel since replacing a bad driver's side failed ball joint with a new control arm. I had the power steering rack replaced about 6 months ago with a used one. A couple of weeks ago, I noticed a vibration while driving between 25 to 65 mph. Would dissipate after 65. Took it in last week for a road force balance on all 4 wheels. Drove away like a brand new car. Made a couple of trips of maybe 20 miles total. Drove it home from work and vibration returned worse than ever. I will have the alignment checked but what else could be causing the problem? It is driven at least 3 times per week so it isn't sitting on the tires.

Don't waste your money on another alignment until you find the problem. It's very unlikely that your alignment will cause vibration, it's more likely your wheels or tires. Maybe a wheel weight came off or a wheel is bent and difficult to balance correctly. If you have a squared setup try swapping front & rear wheels and see what happens. Also, have you checked that your wheel bearings are adjusted correctly?

speed related vibrations are almost always balance. i also would suspect a thrown weight.

however, caster blocks can do it too. take a look at those.

I don't know what brand of tires you have or their age but I had a problem like with with some Goodyear tires. They were balanced previously and had lots of tread. Problem it turned out was separation of the tread from the woven core. I recommend swapping the fronts and rears (assuming they aren't staggered) and see if it goes away. If it does, you'll know quickly. New tires now and runs like it's on rails. good luck

yeah - that'll do it too. i just had one of those on a spare with almost no miles on it.

Take a look at some of your front end bushings, tie rods, wheel bearings and ball joints for wear. I had the same problem last summer with four new tires and an alignment, the front end was shaking. I replaced my tie rods over the winter and problem solved.

Cannot swap the rears for the front - early offset. Probably do need to swap left to right though. I have replaced one control arm and ball joint already. Suspect could be the passenger control arm and ball joint. Will also check the tie rods. These are 16" wheels from an 86 turbo. I did hit a big pothole about a month ago. Maybe I bent the passenger front wheel. They were straight before that incident. Odd thing is appears to come and go. Barely noticed it yesterday. Let go of wheel and car stays straight. Not pulling to one side or the other.

The offset doesn't stop you from swapping the fronts and rears. You can swap them as long as you are not running a staggered setup, ie: front and rear widths different.

99% this will be from the wheel damage. I have a slightly bent front on my 996 and the vibration comes and goes. Balance shop told me it was hard to balance and would probably do this.

It is a staggered set up.

It was a thrown wheel weight. Re-balanced and running smoothe again.

As 9ff mentioned in post #2, I have had a thrown wheel weight and it was intermitant. My Dad put Slime in one of my tires once when I was out of town and I didnt know. Had problems with that til I had the shop take the tire off and they showed me.