Murf,
Like the dukman said, check the "rag joint" or coupler right where the steer shaft connects to the steer box. If the joint is good then.....jack the front end up...have a friend sit in the car and move the steering wheel back and forth slightly while you observe the movement of the pitman arm. If the movement between the steer shaft and the pitman arm don't move together in "sync" or the pitman arm has side to side movement, then the steering box needs to be overhauled or replaced.
Replacement isn't bad to do. You will need a socket of about 1 1/8 or around that size...I forget...for the big nut holding the pitman arm on....a pitman arm puller....impact wrench is a big help...a torque wrench..these are the only special tools needed....the rest of the tools needed are common sockets and wrenches.
Remove the pitman arm with the puller...split the rag joint from steering box...remove 3 mounting bolts...and don't let it fall and hit ya in the head....
To install....center steering wheel...(rebuilt steer box should already be centered) the flat spot on the splined shaft should be facing the 12 o'clock position. The splined shaft w/flat spot slides into the rag joint...it's a pain in the butt sometimes. (tighten pinch bolt after you bolt the box to the frame.)
Once that is aligned... put the 3 mounting bolts back in, 30 ft.lbs./ securing the steer box to the frame...then slide the pitman arm back on to the steering box shaft and tighten down the nut to 140 ft.lbs. manual steering/ or 185 ft.lbs for power steering.
Your steering box should have equal turns left to right from center to lock. For example: 3 turns total lock to lock. Then center to left lock should be 1 1/2 turns. The same for turning right. If your steering wheel is off center, then take it in to have a shop that does alignments center it for you. As I did mine. I hope this helps. The whole job should only take an hour at the most to do. Or longer as detemined by "beer breaks" in between
Good Luck! Feel free to e-mail me. SARGE81vettenut@aol.com Later, Sarge
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GEN III 5.7L "LS6" Engine swap
TKO500 5 spd.
3.54 Dana 44