On our back from the last road trip we took, our LH upper control arm mysteriously loosened itself from the frame rail. We were in stop and go traffic so the constant weight shift back and forth might have had something to do with it. There was a loud bang and the van veered hard left. Luckily traffic was moving slow and I was able to recover and limp off the nearest exit.
Since that nerve rattling episode, right after Thanksgiving, we have had the van in for re-alignment 3 more times! It is on the rack as I write this. Once again, the RH Upper control arm is loose as S**T. The mech said the adjustment bolts were like 4 turns out.
What could be causing the UCA adjustment bolts to nearly work themselves free??? We have really poor roads here in Corpus and the HD suspension on my Ram 3500 Van is pretty stiff, so would vibrations alone be enough to work it loose? I am worried about their being corrosion or cracking or... IDK.
I had my lwr ball joint fail while driving my 99 Tacoma about a block from the house and think I am having PTSD from it all. I can only imagine what'd happen with my big van at any kind of speed, especially with all the family on board. Wife is about ready to have our 7th child, so we NEED reliable transportation.
I would either personally or have the shop inspect the upper control arm hardware for wear and fatigue. Vibrations could work it loose, but the hardware is designed to be used in harsh conditions. Mayeb the original bolts and nuts are worn out and loosening.
I haven't looked close enough to see what kind of hardware is on the nut side or how easy it would be to replace it all. I was thinking I could pull one from the JY and match it up with a Grade 8 bolt that has provision for safety wire. There is a local store here that specializes in hardware where I could probably find something suitable. In Aviation, we safety-wire darn near everything to prevent it from backing off.
I had a weird clunk when braking in reverse, that I found to be a loose bolt on the pivot bar which holds the UCA in place.
There are some ridges on the bottom of the bar for traction that had gotten flattened with my loose bar. I forget exactly where the 'nut' is for the bolts but am thinking it is inside the frame rail.
I think you could get some safety wire around the pivot bar and around the nut to prevent it backing off. I'd perhaps try and wire brush the bolt head and mating surface, wipe with alcohol and rag until it did not get dirty, and then use some lock tite or adhesive on that instead of the threads.
Where the pivot bar is tighened down on the frame rail affects the suspension caster and camber, so an alignment is likely necessary before safety wiring those bolt heads