[rs72z]

Take a pic of the one that's giving you trouble. I think you are referring to the direct drum, the one that goes down on the foward drum.

I was just looking back at the picture of your spring compressor, unless you changed it the U shaped piece is on it upside down. The U shaped piece should go against the spring retainer and the long bar should go on the back side of the direct drum or case for low/reverse piston.