Bump Steer Causes

Measure before changing anything. Fit a bump steer gauge to the hub, support the vehicle on the hub rather than the tire, and record toe at 25 mm intervals through bump and rebound. The plot shows which car suspension bump steer causes are at work: a kink at one end of travel usually points to the tie rod arc, while a steady drift across the whole stroke points to rack height or tie rod length. Correct with spacers at the outer rod end, a drop pitman arm or a relocated rack, then measure again. Set static toe and camber afterwards, because every correction of this kind moves them.

Yes, and by the same mechanism in both directions. Factory geometry is correct only within a fairly narrow band of ride height, so moving the body up or down by 40 mm swings the tie rod and the control arm through parts of their arcs that were never meant to be used together. Lifted solid axles generally need a drop pitman arm or a raised track bar mount; lowered independent suspensions generally need tie rod spacers and often a roll center correction kit. Fitting the springs and leaving the steering untouched is the most common way that car suspension bump steer causes are created.

Collapsed control arm bushings are the usual answer, because a bushing that has lost 3 mm of height moves the inner pivot as surely as a lowering spring does. Worn outer tie rod ends and ball joints add free play that shows as toe change under load, and a bent steering arm or a distorted rack mount does the same permanently. Subframe bolts that have shifted after an impact belong on the same list. Check these before ordering correction parts, since fitting spacers to compensate for car suspension bump steer causes that are really wear will leave the geometry wrong once the worn parts are finally replaced.