The Ford Barn - View Single Post - Re-thinking shortened pitman arm

Houdini · 01-04-2017, 05:58 PM

My car had a lot of play in the steering when I got it, plus it steers hard (which from all that I've read here is not unusual). I have a regular size pitman arm.

Last year, I redid the front end, new king pins, new steering arm balls, etc. That took a lot of the play out, but it still steers hard. I also adjusted my two tooth steering box, to take out more play to where I felt it was acceptable. But there is still some play in the steering box.

some club members suggested I put in a shorten pitman arm to make steering easier. I've resisted as I theorized that although it would make steering easier, it would also increase the "effective" play.

I've thought about that more and perhaps I was wrong. Let me explain about my "play theory" and see what some of you think.

First, play could originate from the steering box or the linkages and front end components. My original reaction to not putting in a shorter pitman arm was centered around play other than the steering box. Why?

Well, the pitman arm's rotation is translated into linear movement of the drag link and so, the shorter pitman arm, means when you turn the steering wheel, say a quarter of a turn, you actually move the front wheels less, with the shortened arm, because the drag link moves less on the shorter radius of the shorter pitman arm. So it makes steering easier, because of the increased mechanical advantage. My concern was that if there is play in the front end components, then the slop in the steering as you encounter grooves and crowns in the road, will mean you have to turn your steering wheel further to correct or check for that, thus making it feel like you have even more play than before.

But at this point, I feel I took out all that play in the linkages and my play is isolated to the steering box itself. So after more thinking on the subject, I am theorizing that a shorter pitman arm might actually make the play less noticeable, because the correction I'm making with play is in the steering box. I'd still have to rotate the steering wheel the same amount to "bump" against the "sides" of the play before my movements in the steering wheel correct the wheels on the ground, but that same steering wheel movement means the play effects less movement of the wheels on the ground, thus controlling steering more precisely.

So assuming there is any validity to this, do you think a shorten arm will make steering more precise or feel like I have better control, as well as the obvious of making steering a bit easier.

I know some of you will simply say I should rebuild the steering box etc, and I was thinking of doing that, but this might be a fix for now that is more affordable and makes driving more fun until I can do the box.

In any event, I'm sure your opinions on my "theory" will be interesting to read. Hopefully, we can keep this discussion on the shortened pitman arm theory and your experience with it.

01-04-2017, 05:58 PM	#1
Houdini Senior Member Join Date: Jul 2015 Location: Central Texas Posts: 113	Re-thinking shortened pitman arm My car had a lot of play in the steering when I got it, plus it steers hard (which from all that I've read here is not unusual). I have a regular size pitman arm. Last year, I redid the front end, new king pins, new steering arm balls, etc. That took a lot of the play out, but it still steers hard. I also adjusted my two tooth steering box, to take out more play to where I felt it was acceptable. But there is still some play in the steering box. some club members suggested I put in a shorten pitman arm to make steering easier. I've resisted as I theorized that although it would make steering easier, it would also increase the "effective" play. I've thought about that more and perhaps I was wrong. Let me explain about my "play theory" and see what some of you think. First, play could originate from the steering box or the linkages and front end components. My original reaction to not putting in a shorter pitman arm was centered around play other than the steering box. Why? Well, the pitman arm's rotation is translated into linear movement of the drag link and so, the shorter pitman arm, means when you turn the steering wheel, say a quarter of a turn, you actually move the front wheels less, with the shortened arm, because the drag link moves less on the shorter radius of the shorter pitman arm. So it makes steering easier, because of the increased mechanical advantage. My concern was that if there is play in the front end components, then the slop in the steering as you encounter grooves and crowns in the road, will mean you have to turn your steering wheel further to correct or check for that, thus making it feel like you have even more play than before. But at this point, I feel I took out all that play in the linkages and my play is isolated to the steering box itself. So after more thinking on the subject, I am theorizing that a shorter pitman arm might actually make the play less noticeable, because the correction I'm making with play is in the steering box. I'd still have to rotate the steering wheel the same amount to "bump" against the "sides" of the play before my movements in the steering wheel correct the wheels on the ground, but that same steering wheel movement means the play effects less movement of the wheels on the ground, thus controlling steering more precisely. So assuming there is any validity to this, do you think a shorten arm will make steering more precise or feel like I have better control, as well as the obvious of making steering a bit easier. I know some of you will simply say I should rebuild the steering box etc, and I was thinking of doing that, but this might be a fix for now that is more affordable and makes driving more fun until I can do the box. In any event, I'm sure your opinions on my "theory" will be interesting to read. Hopefully, we can keep this discussion on the shortened pitman arm theory and your experience with it.