I had replaced the plastic bushings with a wet bolt kit. The bushings supplied appear to be oilite material. Oilite has a granular structure and will break easily. The photos are of bushings with a...
"A spring broke...........Spring eyes are not very round"
Spring breaking and having elongated spring eyes placed a lot of stress/torque on those bushings. How are the holes in shackles.......round or elongated also?
Slop will damage/destroy bushings regardless of material.