Newbee with a P/S Frame TROUBLE

[mtchevytruck]

Bought my first Chevy!! I've owned over 50 vehicles and finally did it.

Picked up a 77' c10 Bonanza that has a fresh motor, lowered, 10" ralleys, with body work in process. Took it out after getting a few known problems corrected and felt a lot of wander and steering play. Thought may be due to the big sneakers, worn parts, poor alignment after being lowered (2"), etc. Got back and had my better half wiggle the steering wheel and to my dismay watched as the steering box rocked back and forth!! Look closer and see evidence of minor tear and wrinkle in inner fender well from this coming loose earlier and welding here and there around the mounting hole areas in the frame. The frame looks fine in front and behind this area and I looked it over pretty well and I'm not finding accident damage anywhere.

I guess I'm wondering if this is a common problem and if there are any recommendations on how to repair it correctly, what caused it, and how to keep it from happening again? I did purchase a 77' 2wd long bed parts truck with no motor along with it, but have not brought it home yet.