The Pitman arm is a crucial component in a Pitman type vehicle steering gear that translates the radial movement of the steering column into linear movement to turn the wheels. It is a flat, offset lever that is attached to the transfer shaft at one end and a ball joint at the other. Regular inspection and maintenance of this critical link is necessary to avoid a loss of steering control.
The Pitman arm is the steering box transfer link in a Pitman type vehicle steering gear. It is the component in the system that translates the radial movement of the steering column or axis into the linear movement to turn the wheels. The Pitman arm is the first of three angular rotation links that transfer inputs from the steering box to the track bar, which in turn moves the left and right tie rods and their respective wheels. The other two links are the intermediate arms that are attached to the ends of the track rod as stabilizers. The Pitman arm is a crucial part of a vehicle’s steering system and, when worn or damaged, can cause a potentially catastrophic loss of steering control.
Pitman steering systems are most commonly found on older vehicles and heavy trucks. Most newer models feature variations of the rack and pinion steering mechanisms. The Pitman system is, however, robust and reliable when properly maintained. These systems generally consist of a bar that extends from the steering wheel, through the front firewall, and into the engine compartment. Here it enters a steering box where the axis of its movement is turned 90 degrees to drive a short transfer shaft by means of a worm gear and a nut or roller arrangement.
The Pitman arm is a flat, offset lever that is attached to the transfer shaft at one end and a ball joint at the other. A link arm is attached to this ball joint and a similar joint on the track rod. The track bar, in turn, is ball jointed to a set of tie rods at each end. The tie rods connect to the wheels via articulated steering arms. When the steering wheel is turned, the shaft moves the Pitman arm through a short arc which then pulls the trackbar to the left or right.
When the track rod moves, so do the tie rod/steering arm assemblies which cause both wheels to turn in the same direction and steer the vehicle. The trackbar is also supported at each end by a pair of intermediate arms that keep the trackbar/rod assembly stable and at the correct height. Therefore, the Pitman arm represents the main actuator for linear steering movement in Pitman steering systems. It goes without saying that a worn or damaged pitman arm will cause a loss of steering feel or worse, i.e. a complete loss of directional control over the vehicle. This makes regular inspection and maintenance of this critical link a must for any vehicle maintenance regimen.
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