Why is there a ball joint in a pitman arm?

[ChargerST]

I just wondered why there is a ball joint in the pitman arm but not on the idler arm. I just got a new pitman arm because I thought the old one had play (I assumed that the pin should just rotate but not move sideways when steering). Turns out the new one can be moved in any direction just like the old one. What's the purpose of that? Wouldn't it make more sense to design the pitman arm like an idler arm where the pin can only rotate?

[71charger_fan]

I'm going to take a guess and say it's because it's attached to the steering gear and having the ball joint in the arm reduces the stress on the steering box. The idler arm mounts to the vehicle structure where stresses imparted by the arm won't cause bind to other moving parts.

[bull]

That sounds like a very good guess.

[John_Kunkel]

Two reasons, the idler arm is mounted in a rubber bushing and can flex up/down allowing the center link to move up/down and to allow for mass production misalignment.

Also, according to a recent article by Rick E-booger, there is significant flex in the steering box mount allowing the pitman arm to move around in relation to the K-member (he advocates use of a kit to stiffen it).

[ChargerST]

Two reasons, the idler arm is mounted in a rubber bushing and can flex up/down allowing the center link to move up/down and to allow for mass production misalignment.

Over at moparts I saw a thread where a guy recommended replacing the soft foam bushings/gaskets of the idler arm with nylon to firm things and reduce flexup. Good idea?