Hey guys so I’m starting to tear apart this hst I purchased. I did a compression test and got 240,220 and 100 psi. I have the pistons soaking in acetone and atf, I’m going to see if that help break up some of the carbon. The other thing I can’t seem to find is the serial number or my tractor . It’s B7100HD67172 , can’t seem to find it on any website