Broken rivets cause creaking an popping but so do ball socket suspension parts an bushings. If you think its a rivet, tap on it with a hammer..... if it makes a hard metal sound its good if it sounds hollow an dull then its broken. its actually very easy to tell the difference. Also cracks an very rusty sections of the floor where its eaten thru cause creaking.
Theres also the #1 cross member rivet (cross member under the engine) where the power steering box is..... problems with those is the rivets bust an the front of the frame shifts around rubbing on the cross member causing that popping an creaking. It can be repaired but the problem is the window to get into that spot where that rivet is hidden somewhere behind the dual shock bracket which is also riveted. There are 3 rivets on the frame rail an the first one is the #1 cross member rivet an its also the only one you cant get too on the other side to fit a nut or bolt without taking everything else off.
My other bko which is an 83 has a single shock setup an i still dont see a "window"
I have this problem but the popping is from the tie rod and/or ball joint which both need replacing anyway the only way i found it was looking under the truck as someone turned the wheel back an forth an saw the frame move slightly. An then did research an found the tsb they suggest drilling out the rivet an using this non slip insert to put in between the cross member an frame an bolt them together with grade 8 bolts. I had the inserts sent to me from ford which cost about 40$ for a 3inch by 2 peice of carbon fiber but i didnt no thats what it was......oh well
Also when im done with my brake problems Ill be tackling this rivet problem. A friend of mine who also has a bko had his front bumper off while doing his SAS an i think i may be able to slide my arm just far enough in the frame to get to where i would have stick a bolt thru the hole that would be drilled. That or cutting a hole an welding on a support either way since its been flexing alittle im gonna weld a support plate an a support from one frame rail to the other right behind the bumper but thats after i get everything aligned again.
i had a gear box leak at the time