I took it off again and chucked it up in the vise. I removed all the control piping and rigged up a come-a-long to the workbench. I used that to pull the shaft about 5" out of the cylinder. That cable was as tight as a banjo string, there must be a big spring inside the cylinder to help offset the weight of the saw arm, sort of like a counter weight.
I then filled the cylinder with hydraulic fluid using the hole furthest away from the shaft. I then slowly released the comealong and let the shaft retract back into the cylinder. I stood the cylinder vertically in the vise and then filled it with more oil using the top hole. This should have gotten it as full of oil as possible on both sides of the internal cylinder piston.
I put it back together and tightened all of the plumbing to ensure no air or oil leaks. I put it back on the saw and it works like before i.e. the saw arm goes from vertical to about a 45 degree angle before the cylinder catches it. With the valve closed it holds it without let it leak down. When you open the on/off valve and just barely open the speed valve, it slowly lowers the saw.
So, its back to working like before. I cycled it 20-30 times over a 20 minute period and it kept working. I'll let it sit for half a day like yesterday then check to see if it has stopped working again or if its really fixed this time.
Randy Rosetta KDØKWX TLCA #19351 69 FJ40 "Meanie" & 1970 Boss 302 Mustang