Malcolm, I am still confused. Here is a descirption of all the screws in the main gear:

If you are talking about the pin that attaches the strut to the retract trunion, there are two grub screws in the trunion and two in the strut. The two screws on the trunion are only accesible with the gear down.

There is a cap head screw that retains the brass slider bar that fits in the oleo channel attaching the lower strut to the upper strut. FWIW, mine came loose in a couple of flights -- make sure they are loctited in.

There is also a grub screw in the based of the lower strut to hold the axel to the strut.

Another FWIW: the axels with this plane are made of very soft metal. You can actually grab the wheel and bend the axel with your bare hands. If you land hard, make sure to inspect this point and rebend the axels to 90 degrees or the wheel will rub on the strut, or press up against the upper wing surface when retracted and possibly not release when down gear is called for.