The steering gear and linkage are vital safety concerns—yet the pitman arm on a 4WD Jeep or other light 4x4 truck can easily be installed incorrectly. With the popularity of oversized tires and suspension lift kits, many pitman arms get replaced long before there is a parts wear issue. A dropped pitman arm is often part of a suspension lift kit, and the pitman arm on a new or relatively new vehicle may get replaced with a dropped arm.
Here are some procedures that I use when installing a pitman arm:
1) Never turn the arm against either of the steering gear's extreme left or right turn positions. Force against the gear in these positions can damage the steering gear internal parts—the gear is not intended to absorb this kind of force at either end of the worm or ball nut's travel. I like to keep the steering gear and pitman arm close to the center or straight-ahead steering position during pitman arm removal and installation.
2) When removing the pitman arm nut on a typical steering gear, there is a lot of force required. It is easier on parts to use an air impact gun and socket to remove the nut, as there is less tendency for the pitman to rotate...If you have the steering gear removed from the vehicle, consider holding the arm in a large bench vise (with the gear assembly free) while loosening or tightening the nut.
3) Once the nut is removed, use the correct pitman arm puller tool to prevent damage to the steering shaft and other parts. Make sure the tool fits properly between the backside of the arm and the neck of the steering gear housing, with enough clearance to prevent damaging the housing/casting!
4) There is considerable force with the pitman arm secured on tapered splines, so use extreme caution with the puller tool. Once the initial tension relieves, the arm will come off readily.
5) Clean up the sector shaft splines as needed. It is critical that the new pitman arm fits properly, an interference fit that demands clean mating surfaces. If installing a powder coated aftermarket pitman arm, I always use a suitable drill motor-powered wire brush to remove the powder coating from the tapered seat and splines of the new pitman arm. (I remove paint here, too.) Don't damage or dull the spline teeth in the process!
Warning: If you mate a powder-coated part at the splines, you will get a false torque reading. There is a high likelihood that the pitman arm will loosen at the splines as steering force wears through the powder coating. If you have a powder-coated arm already installed, and if the arm has been in service, re-check the nut torque with the pitman arm in the straight ahead steering position.
6) Always use the required torque wrench and socket to bring the sector/pitman nut to proper torque. Again, make sure the arm is near the straight ahead steering position to prevent damaging the steering gear. The torque required is high, especially on a recirculating ball-and-nut power gear, much more than on a light-duty vintage Jeep cam-and-lever gear! Do not second-guess the torque setting. Use a factory or professional shop manual to determine the correct torque for the pitman/sector nut on your steering gear.
7) When reattaching steering tie-rods, make sure they are clean and free of debris. If the outer end of the new pitman arm has a tapered seat with powder coating or paint, I use a drill motor-powered wire brush to remove the powder coating and take the tapered seat to bare metal.
8) Attach a clean tie-rod ball stud to the pitman arm tapered seat, using the correct type nut (typically castellated or flanged self-locking) that comes with the tie-rod end. Flanged, self-locking nuts are often one-time use only. Consult the factory workshop manual for recommendations on replacing fasteners or use of thread locking liquid. Always use OEM grade hardware and fasteners.
9) Align steering joints, adjusting sleeves and tie-rod ends so that the ball studs are on center with the steering linkage aligned. Make sure none of the joints bind or run out of travel over the full range of steering turn positions and angles. Make sure that parts do not interfere with each other.
10) I always recheck the torque on the pitman and tie-rod fasteners after a short time in service. This is a safety precaution that may catch a part requiring a slight re-torque.
Again, this is all about safety. Use of oversized tires places an even bigger load on these parts...