There are two basic types of pitman arms: wear and nonwear. Service needs differ, depending on which type of arm is used. Nonwear arms have tapered holes at their center link ends and normally need to be replaced only if they have been damaged in an accident or have been mounted with excessive tolerance. Wear arms have studs at the center link end and are subject to deterioration from normal operation.
To replace a pitman arm, you should:
- Raise and support the car on a hoist or jack stands.
- Remove the cotter pin and nut from the pitman arm/centerlink stud. Break the taper on this stud, preferably with a puller, and separate the Pitman arm from the centerlink.
- Mark the arm-to-pitman-shaft position and loosen the retaining nut several turns or until it is even with the end of the threads.
The nut should be left on the pitman shaft to help protect the threads and to prevent the pitman arm from popping completely off.
- Install a puller and tighten it to break loose the taper between the pitman arm and shaft. Remove the puller, the retaining nut, and the pitman arm.
A pitman arm puller. Courtesy of Moog Automotive, Inc.
- Clean and inspect the splines on the pitman shaft, the splined hole in the pitman arm, and the hole and stud at the centerlink connection. Pitman arms often have a "blind spline." One wide spline ensures that the pitman arm can only be installed in one position.
- Align the marks between the pitman arm and shaft or turn the steering wheel to the center-most position of the steering gear with the steering wheel centered, and slide the pitman arm onto the pitman shaft. It must be replaced in the same position on the splines of the steering gear. At this point the pitman arm should be positioned either straight, to the front, or to the rear.
- Install the retaining nut and lock washer on the pitman shaft, and tighten the nut to the correct torque.
- Tighten the pitman arm or centerlink stud retaining nut to the correct torque and install a new cotter pin.