swop over both front wheels across the axle to the opposite side ,so that near side and off side wheels change places, then road test on a flat-ish road.
this cures or pinpoints the fault in 90% of steering pulling over cases.
the problem is due to a soft wall on one of the tyres,this causes the tyre to roll along like a cone when weight is put on it,making the steering pull towards the side with the faulty tyre.
give it a go - costs nothing to try,you may be very
supprised. i have cured many hgv trucks by trying the simple wheel swop test.
berty, October 2008