If your old car or truck seems to have a mind of its own as you drive down the road and the steering wheel chatters with every bump, you may need a new pitman arm.
The pitman arm, also called steering arm, links the steering box at the bottom of the steering wheel shaft to the track rod which is attached at the other end to the idler arm. When the steering wheel is turned left or right, a worm gear at the bottom of the steering shaft turns a set of teeth. That action moves a gear that activates the pitman arm, causing the steering linkage to move the wheels.
The steering arm is part of an older recirculating ball steering system which is still used primarily in some full-size SUVs and trucks as compared with the smoother-handling rack and pinion steering mechanism more commonly used in automobiles.
A properly functioning pitman arm precisely directs the movement of all the other steering links, limits wheel wobble on bumpy surfaces, assures full wheel turning radius and helps to reduce steering wheel vibration.
