Hello Joe,
Wear may be noticed on the threads of the a-arm collars and the threads of the "caps". Some wear may not be an issue since the critical "movement" and wear occurs at the threaded hing pin and the cap and not at the a-arm collar and cap. The suspension a-arm hinging action occurs at the cap and threaded hinge pin connection. The cap and the a-arm collar remain locked together after being tightened and minor wear becomes irrelevant since no movement can occur there after tightening. Under some circumstances the cap can come loose and the A arm hinging action begins (wrongly) occurring at the cap and collar instead of at the cap and threaded pin. in this case sever wear can happen in this area, which is not normally intended for this kind of movement. When severe wear happens at the cap and a-arm collar, the cap may become too loose and be impossible to tighten.
I have seen the collars and caps get worn so much that the caps simply insert into the collar of the a arm without being "screwed in". Severe wear at the collar of the a-arm or cap is unusual, but must be resolved by replacing the A arm and/or the cap.
