While I was doing all that heavy lifting on the cartridge I found that there is no set screw holding the spring and plastic bit that maintains pressure against the 'way rod' to keep the 'rider weight' from slipping. Something on the plastic bit must have worn off and they slipped out.Not wanting to trust the 'rider weight' to stay put by itself I tapped the hole with a 6-32 tap and installed a stainless steel set screw. The hole is of a size that it's just what you'd drill for a 6-32.