I have a lot of experience on L-23 loose horizontal stabs. The first thing I would check is the fit of the pins. The maintenance manual will tell you the exact maximum number. You’ll need to measure the OD on the pins and the ID on the rocker assembly. Stock pins are pretty easy to find, oversized not so much. If you have to oversize you’ll need to ream the rocker assembly.

Clean and plenty of grease when the horizontal gets put on.