I was checking out the steering box to box mount to frame connections today by turning the st. wheel on pavement. All that looks good, everything tight no visible cracks etc..
But, holy cow! the frame rail was moving alot at the top, esp. noticeable in relation to the bottom of the rad. core support.
No noticeable defects, just alot of frame flex. Has anybody else noticed this?

 

I think that you have a problem -- I have been doing some steering trouble shooting on my truck, and while there is a fair bit of flex in the springs and spring bushings, I did not find any flex in the frame as you are describing. (I actually replaced my front eye bushings with poly bushings, which reduced the flex there considerably -- we'll see how they do over time). It seems like you may have a busted rivet or something. . .

 

The rivets can be problematic. I had mine replaced with bolts and the frame rails welded. No more flex for me!

Carl

 

I was underneath myself checking things on the front end when I noticed that bolts to the spring arches to frame were loose. I tighted them up and truck doesn't shake nearly as much. LOL. Now time to replace the rubber spring bushings with the poly bushings. For $ 20 - $ 25, how can you go wrong. After 200,000 miles on the stock rubber one, I am sure it will make a difference to have new Poly ones in there.

 

This week I replaced my steering gear box and pump w. Napa rebuilts. I've had problems for quite some time and finally got quite a scare at 70mph, suddenly I could hardly keep it in my lane. It wandered back and forth w. steering wheel input barely keeping it in check - it was real strange. I pulled off to check it out, couldn't find anything wrong so I reluctantly got back on the freeway and had no further problems the remaining 30 miles - real strange!
Needless to say, I pulled the steering box that night; the next morning got parts, finished the R&R that afternoon and evening. Still haven't tracked down that frame flex. The mounting plate and frame were good and tight w. no cracks.

brick

 

The final chapter on steering - I hope!
After replacing the st. box and pump everything was good - for about ten days. And then it did it again :'(
Sooo, I checked everything again. I popped the tierod loose to separate the two sides. The left side worked fine turning but the right side was real stiff. Then it dawned on me that the axle u-joint could be the culprit. Then I lined up the axis of the u-joint with the knuckle and it wouldn't turn! Rotated the axle to line up the other axis of the u-joint with the knuckle and it jerked and ratcheted when it turned. I guess what was happening is that every now and then that axle would rotate thru road vibration to the point where the u-joint couldn't rotate and wreak havoc with the steering.
So, check your front axle u-joints, mine with 108K miles were toast - even the "good" side was ready to fail.