GM-GMC: 1986 silverado steering, front wheel bearings, frame cracks

Question
I have a 1986 silverado 4wd short bed.  I was driving to work the other day and went to change lanes and my steering jumped to the left. I attempted to correct it and it jumped back to the right.  It did this the entire way to work (couple miles) where i proceeded to check everthing over.  I had this problem in the past, approx. 4 months ago and was told it was due to a crack in my frame.  I have since gotten my frame welded and it was fine since then.  I checked my frame over and there are no new cracks and the welds are all fine.  I was told that it could possibly be the steering box or possibly a knuckle.  Is this a common thing among older silverado's of this era?  I was shown a couple of them in the same time frame where the frames cracked in the same place as mine. I am wondering if the frame crack in the past may have pulled something loose in my steering possibly causing this issue?  any help that you could give would be greatly appreciated.  thanks

mike

Answer
Mike,

I have heard of the cracking problem, but I have not seen one yet.  I have also heard that lift kits may cause frame cracks.  My 84 K-2500, at OEM ride height, has not had any problems over its 100K+ mile life so far.

However, what you are describing is EXTREMELY dangerous.  Please do not drive the truck around other vehicles until you get it repaired.  The entire steering system needs to be checked, including the tie rod ends, Pitman arm, etc.  Check the front wheel bearings for problems, too.  

It could be a problem in the gear box or a steering knuckle, as you mentioned.  But if it is, one of the parts is likely to fail and possibly cause you to lose control of the vehicle.