S4 Steering

[cmdrew]

Hi All,

I have previously posted that I have replaced all 4 upper control arms and in the process ended up replacing the alloy uprights and track rod ends. What is concerning me now is that the steering doesn't feel 'right' after the changes. Could just be me worried that I have done something wrong but the steering seems a bit dead around straight ahead and when turned it initially seems quite light for the first 20 degrees or so and then gets heavier. The variation in feel is quite disconcerting and doesn't inspire confidence in the handling.

Now I tried to set the control arms to the right 'height' when tightening them up off the car but I wonder if I have got this wrong and the pre-loading of the control arm bushes is the cause of the vague steering? Not sure how else to set up the position though as very tricky to get to when the wheels are on! I have measured the distance from the wing to the wheel hub centre and it is the same both sides but I have considered jacking the car up, removing the wheels and then jacking up under the hub until the distance from the hub to the wing is the same as when the car is one the ground. I could then re-tighten the inner top control arm bolts which should ensure that they are pre-loaded to the correct position. Any thoughts or am I just being paranoid?

 

[dualmono21]

ideally you need the car 4 wheel aligning if you have changed any of the suspension geometry
there is a very good place in sheffield near me which does an excellant job and will set up both the front and rear of the car correctly

 

[hades-]

you need the alingment doing

 

[cmdrew]

ideally you need the car 4 wheel aligning if you have changed any of the suspension geometry
there is a very good place in sheffield near me which does an excellant job and will set up both the front and rear of the car correctly

I did get the tracking done and the car is set correctly - before it was done the tracking was so far out that the traction control light kept coming on!

 

[hades-]

who did it what machine
and did you get a print out ?

 

[cmdrew]

It was only front tracking and was one of the manual Kwik-fit type alignments. I watched the guy do it and the rear alignment was correct and he set the toe out to 2mm I believe. Apparantley it was supposed to be +2mm +- 0.5

 

[dualmono21]

doesnt work like that im afraid

you set the rear of the car up first .... this ensures the thrust angle is correct then and only then do you do the front

on the rear you have adjustment for toe in and out and camber
the correct settings for camber are -0 degrees 50 minutes to -1 degree 50 minutes
the correct settings for toe are 0 degrees 8 minutes to 0 degrees 15 minutes

total toe should be between 0 degrees 15 minutes and 0 degrees 30 minutes
thrust angle should be as close as possible to 0 degrees but allows for 0 degrees 7 minutes either way

by balancing the toe and camber on both sides you align the thrust angle so it is in the middle of the car and also alter camber settings on the front

when this is done you can adjust the front

toe settings are 0 degrees 5 minutes to 0 degrees 15 minutes
camber settings should be 0 degrees 22 minutes to 1 degree 12 minutes
contrary to popular belief the s4 does have a small degree of adjustment on camber settings

 

[hades-]

your last post was your answer you used kwik fit

and post above is how it should be done

 

[cmdrew]

Well just had a 4 wheel alignment done and TBH it wasn't that far out anyway. Rear wheel camber was quite a way out and the tracking was a bit out. Does seem to drive much better now but that's probably psychological!

 

[hades-]

even tho the front wasnt to much out
the rear been quite a bit out is enough to throw the steering off.

did you get a before and after print out ?

 

[cmdrew]

Yes - before the Rear Drivers side was at 0.25' toe with the nearside at 0.09'. Now I have 0.12' both sides. Camber (rear) is -1.36' and -1.31'. Thrust angle is -0.01' so pretty good. Front toe is now 0.2' whereas it had been 0.34' so it wasn't that far out. Only trouble they had was with front camber which is out of spec at -2.14' and -1.28'. They said that the camber was adjusted by moving the subframe but as both were negative improving one side would push the other further out.

 

[dualmono21]

they are correct in saying that to adjust camber you loosen the subframe bolts and move across and re-tighten
and since yours are both allready negative you wont get an improvment

you may have to look at the ball joints on both sides of the car if the camber is that far out
it may well start eating tyres on the insides
ive just changed all mine and put on a new koni suspension kit and its now reading just outside the 1.12 spec limit