After soaking all the nuts and bolts in PB Blaster for the last year, I am finally, gingerly, disassembling the pump. Using all of the great info on this sight, I have carved out the sealant and am loosening the bolts 1/4 per day. So far, so good.
Tonight, I got the top cover off of the cylinder and could finally see inside. One broken gallons indicator rod, but everything else looks good.
As a curiosity, there is a vent tube at the top of the cylinder that goes to a very small hole. I am not suprised to see a vent, but it appears to have a valve hooked to it inside the cylinder instead of just an opening or tube.
Why a valve? Were there applications (air operated maybe) where they would want to choke off the vent?