Case 580k dipper cylinder piston cap screw size

The dipper cylinder started leaking from the gland when I was pushing on a tree. I want to get tools together to take to the machine which is at a remote location and am trying to find the size of the piston cap screw head so I can get the right size 1" drive sockets. The machine is an '87 and the dipper cylinder shaft is 2.5". The service manual does not mention the size of the cap screw.

Same for my stabilizer cylinders. Shaft size on stabilizer is 2".

Btw, after heating the cap screw to...

Case 580k dipper cylinder piston cap screw size

Case 580k dipper cylinder piston cap screw size