Sorry for the lenghty post....I feel like there is a little too much slop in the steering ('78) so I checked out some older threads on the subject here. Its hard to keep in the same lane sometimes. I've replaced just about everything steering related.
Some here advised to get the car up on both front wheels and then turn the steering wheel back and forth to feel for any strange -feeling spots in the travel of the wheel.
I did this (w/ the car off) and the only thing that I did notice is that there is some slack in the change of direction (transition) when I move the steering wheel from left to right OR right to left. In other words, if I turn the steering wheel to the right, stop, then turn it back to the left, there is a dead spot (steering wheel turning but no movement of the wheels) before the wheels will turn back to left. My guess is 2" or even more.
So I had my wife get in the car and turn the steering wheel while I got under the car. Instant responses noticed from the steering column to box to pitman arm. However the connection from the pitman arm to PS control valve showed the same slop that I experienced when I turned the steering wheel. Turn right or left, pause, then turn the other direction. I could see that pitman arm to control valve "pause" (have a dead spot) before it eventually "grabbed" and then started turning the wheels.
Should that Pitman to PS control valve movement be instantaneous like the other steering parts were? Or is normal for there to be that "pause" in the change of directions?
I am just wondering if I am onto something or not..

 

if you really trust her try again with the car running.you will have play there with the car off.

 

Is your power steering belt connected? If by chance you are driving without the p/s connected that would also explain it. Guess how I know...

 

Ok - I'll try it tomorrow with the car running. Yes- the PS belt is on.

 

I don't think you should have that much. That is probably a large portion of your issue.

Check your steering coupler too. My 76 had more slop than you would believe. I got under there, did the same thing as you, and settled on the idler arm being the problem. I ordered one and then noticed that my rag joint was completely shot. I replaced that, and the steering is nice and tight. Still haven't replaced the idler arm.

 

You were exactly right. This time there was no play there when the car was running. hmm.

 

and glad you lived to tell about it.best of luck with your car.

 

Actually I don't feel any play in the steering wheel at all when the front wheels are up and the engine is running. Only when the car is off or is in motion do I feel the play.

 

Check steering control valve.......if there is slop where ball joint connects to tie rod you will get wandering while traveling on highway.
The control valve can be rebuilt...make sure you get complete kit,not just the seals.
Good luck

 

working on these cars can be very frustrating.would you think rear trailing arm bushings would affect steering,i didn't think so but found the whole control thing related to steering.after replacing them i find the car wanders less and the steering feels tighter,even though i did not change anything in the front.and it's not aligned yet and i tested it with 1/4" rear toe out.should be much better when rear toe is set.seems like everything has to be right ,front and rear for these cars to behave properly.especially at highway speeds.

 

Trailing arms recently rebuilt too

The only other clue that I noticed is that rear strut rod bushing near the adjustment bolt is all twisted looking and mangled (on one side). I would think that this would cause it to wander but not necessarily cause play in the steering wheel.

What would cause the steering play when the front wheels are on the ground (driving) but not have play when the front wheels are off the ground.?

 

what comes to mind is ball joints first because they are loaded by the spring.also a- frame bushings and to a lesser degree,the idler arm.btw the redesigned moog idler arm is a world of difference over my original delco.

 

I found that most of my slop was where the pitman arm connects to the power steering control valve, I replaced that now most of the play is gone, next is my rag joint - I was that was wore out when I was underneath replacing PSCV.