hi all.
i have a1986 series 3 xj6
recently started having a problem the other day in which under sudden acceleration or acceleration at too high of a speed in general causes the car to pull HARD to the right and once the gas is let go of you can feel the car self correct and go straight again.
while pulling the steering feels extremely loose almost like driving on ice.
ive recently replaced both front shocks as well as the rear passenger wheel knuckle hub ive just had the front end aligned today everything seems within spec execpt the front caster on both wheels and rear camber on the passenger side.
i havent done anything to the IRS so i fear thats staring to fail although im unsure.
it may be useful to add this started suddenly, at least a week and several hours of driving after replacing the shocks (the last work done on it) so it was driving perfectly fine for a while after having had that work done.
any suggestions or advice is appreciated thanks for the help.

 

check the steering Rack for any side-to-side play. Could be worn rack bushings.

 

Were there any pulling or steering problems before the new shocks and rear hub work? If not, the rear hub that was worked on is the first place I would start looking. Did you do the work yourself? Why was the rear hub replaced/repaired? I would look at the trailing arm attachment bolts along with shock bolt and large control arm/hub bolt where they connect to the control arm.

You mention an alignment was done, except front caster and the camber on rear passenger side. In other words, you didn't have an alignment done. Why couldn't those critical adjustments be measured/corrected and were you given a work sheet showing the alignment numbers when they were done? When you accelerate suddenly, does the car most feel like the front tires are actually moving the car to the right or does it feel like the rear end is moving to the left and making the car feel like it's moving to the right? To get a quick idea the rear (or front) camber, drive onto a flat surface big enough to hold the whole car, like a shop floor, and find a simple framing square or anything that is accurate at 90* with legs about 2' long. Stand it up next to the tire with one leg against the floor and right angle to the tire and the other leg standing up against the tire as close to the center of wheel as you can. If you see a little daylight between the top of the square and the tire, and the bottom of the square is against the tire with no daylight, the camber is roughly OK. If you can see 1/2" gap or more at the top, too much negative camber. If there is any gap between the bottom of the square and the tire, too much positive camber. Both conditions need to be adjusted.

If the front feels like it's actually steering to the right, not enough caster can make the car "twitchy" and want travel anywhere but straight down the road. Just replacing the front shocks should not affect the steering geometry. If you took your car to an alignment shop, there's a better than even chance the suspension on your S3 is like a unicorn to them, most shops just don't see them often or at all and do not know how to make the adjustments. Look at the front suspension thoroughly, especially the tie-rods, check all the bolts/nuts for tight. If you had the work done at a shop and are on good terms with them, tell them what's happening and see if you can talk it out.

In any event, my advise is to check the work on the rear hub replacement and find someone who can measure the current alignment angles and understands how to make the adjustments to correct them. I would hold off driving it until the problem is found.

Dave

 

None of that is very reassuring

"Seems within spec"?

And caster has can have a very big influence on steering feel and behavior


I fully agree with Jose that the steering rack bushings are the first things to check. If those are OK then the problem, given how severe it it is, shouldn't be that hard for any decent suspension/alignment shop to locate. Worn bushings or ball joints, broken subframe mounts (front or rear), very loose wheel bearings....

Something is shifting under hard acceleration that cause the steering or suspension geometry to go out of whack

Cheers
DD

 

As well as the steering rack bushes, look at the radius arms on the rear axle and see if their bushes have deteriorated/disappeared/come loose.

 

Hi all figured id give an update here.
many of you were correct in the assumption the first shop i took it to didnt do much of anything. i didnt really want to think this at the time as they have treated me well before in the past but oh well what can you do.
i took it to another reputable shop in my area that handled the situation much better. they advised me that the trailing arm bushings were completely shot and it was a likely culprit of the problem.
during the process of removing these bushings i discovered the bearing for my passenger side rear wheel was also quite worn.
I THEN discovered my rear breaks were essentially non existant.
at that point i sighed heavily and began work on removing the IRS.
am quite nervous about this procedure but theres plenty of detailed info out there much of which comes from many of you lovely folks.
as always the help has been much appreciated.
expect more questions in the future as i inevitably discover more problems. :P

 

Good to hear, glad you could find a reputable shop. Good luck.

Dave