The pistons in picture # 4 surprised me, I couldn't figure out why a particular pump was making noise and not building good pressure. I replaced the packings, inspected the rods for slop on the crank, and it wasn't until I was removing the ceramic pistons for a closer inspection that I noticed the slop in the assembly. The wrist pin holes were several MM out of round causing low pressure and some strange noises.
After checking my pile of old parts I found some that were ok, but I was surprised at how many were bad.