we had the same problems with all Southco-locks. Some of the O-rings were worn out, most of the pins were bent.
It was a problem to get O-rings with the same specifications. Finally we used O-rings with the following dimensions: Inner diameter 10 mm, outer diameter 13.8 mm, cord thickness 1.9 mm. A slightly thicker cord also works, but makes it difficult to insert the O-rings. It is important to grease the O-rings well.
We replaced the original pins with shear pins for the propeller of the Honda Bf 2.3 outboard. Diameter 3.3 mm, length 23 mm. Honda sparepart number 58131-ZV0-000.
It is necessary to drill out the diameter of the pin hole slightly to 3.3 mm. The pin can then be inserted with contact adhesive. However, it also works without adhesive, the spring pressure holds the pin in position.
SV Mago del Sur 54#40
currently Villasimius, Sardinia