Join Date: Jul 2007
Location: New Zealand
As davealfa11 and Zulu Ferret said, sometimes one of the track rod threaded ends is seized in the rack end, and the workshop decide not to bother adjusting it. Or, both are seized and they decide to only free-off and adjust one of them (meaning, total toe can be made correct, but steering can be left off centre). Usually, heat from a torch is useful to break the corrosion-caused seizing. Trouble is, use of a blowtorch probably has all sorts of health-and-safety ramifications these days... to say nothing of liability insurance...
My wheel alignment shops actually get me to check whether the rack ends are seized, and if they are seized, they won't start the job and send me home instead to wrestle with it!
If steering is left extremely off-centre (say, more than 10mm) you get tyre-scrub problems in full-lock slow-speed manouevring (strange squelching noises and jumping feeling).
It is possible to have a straight steering wheel yet loads of toe-in, causing unwanted tyre wear and a strange steering feel. The toe-in happens not just from worn bushes, but also from striking a kerb (tweaking the control arm), or flexing/sagging of the body structure on some cars (my Uno springs to mind). The latter might not occur with the 156 but I'm sure some people have struck kerbs and put their alignment out - it happens on any car. Or, replacement parts are often a slightly different dimension.
Conversely, a changed set of tyres (particularly if changed left-to-right) can upset the steering wheel angle even if the toe is correct, due to subtle differences in response of tyres. Tyres are often not equal, even in two of the same type.
Finally, road camber is a problem. Lots of camber (slope to the left) and of course the steering wheel will have to be turned to the right to maintain a straight line. Most alignment shops will point that out and some will even try to tweak the caster or camber to compensate (those angles are 'non-adjustable' but I have seen large levers/slotted holes/sledgehammers used). Fortunately, cars like the 156 with lots of power assistance tend to have lots of caster (stability) and fewer turns lock-to-lock, so the amount the wheel must be turned is reduced.
I believe all this becomes more of a concern for cars that have VDC (Vehicle Dynamic Control - Stability Control, ESP, fitted to 2002-on 156), since VDC depends on a steering angle sensor (behind the steering wheel) to decide on the intended course (compared to the accelerometers and wheel speed sensors that report the actual course) and therefore, decide when to intervene with braking actions. If there is a faulty comparison, that could lead to faulty decisions. Therefore the VDC sensor must be 'zeroed' (using Examiner) with the steering set to travel straight. Rather than re-zero, it would be more practical to assume that it was zeroed with the steering wheel straight, and therefore adjust the alignment to get the steering wheel back to straight.
'00 GTV V6, '08 FIAT 500, shell and parts for a '71 FIAT 850 Coupe
Last edited by alexGS; 07-04-10 at 14:26.