We hadn’t had any trouble with backhoe to tractor pins coming out. Keeper cross pin in the right slot. Change between 3pt and backhoe quite a bit. Your keeper cross pin’s straight?
The B26 still has the OEM quick attach bucket lynch pin. Brush and root-balls are great pin removers. M59 bucket QA has double nut bolt after loosing several lynch pins. Did weld a scrap tab to head so only need one wrench. A single lock nut would work too. Old Ford 4500 had regular single nut and bolts for pin-on buckets. Used dirt and mud for temporary locktite. Never lost one.
The B26 still has the OEM quick attach bucket lynch pin. Brush and root-balls are great pin removers. M59 bucket QA has double nut bolt after loosing several lynch pins. Did weld a scrap tab to head so only need one wrench. A single lock nut would work too. Old Ford 4500 had regular single nut and bolts for pin-on buckets. Used dirt and mud for temporary locktite. Never lost one.