Maytea
Thank you for the photos. I will study them closely. Could you plse post pictures of the pump and reservoir.
Although not part of your issues now, the use of galvanized or iron pipe fittings can be very dangerous. They are not designed for the pressures in a hydraulic system. Your local hydraulic supplier can provide a steel fitting for almost any need.
For example, tractor manuals caution owners against putting their hand over what they think might be a tiny leak of hydraulic fluid as the pressure of the tiny jet will be so strong it will force the hydraulic fluid under your skin. That is a very serious injury and if it happens to you get to a hospital immediately!
They suggest holding a piece of paper or cardboard to confirm the presence of a leak however, the natural reaction is to hold your hand out flat over the possible spray.
I would like to relate to you a problem with a pressure washer to illustrate a point. I have a commercial electric pressure washer. It runs around 1200 psi so not high by hydraulic standards.
My brother borrowed it and I did not get him instructions. He connected a hose and plugged it in. As soon as he pulled the handle to spray, the pump went into overload and nothing came out the tip. He tried to remove the tip and could not get the quick coupler to release.
Same for all other quick couplers. When I got there an hour later, I too found everything so tight that removal of a coupler was impossible. Finally I started unscrewing a pipe fitting and suddenly there was a release of air. Now the couplers would easily disconnect.
Looking at the inside of the spray tip I could see about a thimble full of fine mud most of which came out when I tapped the tip on the table. I rinsed the tip out and could see daylight thru it.
I started the pressure washer up and ran it for a couple of minutes with no tip to flush out any sediment and rust, put the tip back in and it was good to go.
A tiny blockage can produce big symptoms. I know you said you connected the two cylinder hoses together and the symptoms were the same.
What I am going to suggest is to disconnect the two cylinder hoses and let them discharge into a clean container. Put a rag over the container to contain any spray.
It is possible that the cylinder packing or other bits have logged themselves into a fitting like a perfect plug. If oil does not come out both hoses as you move the valve handle back and then forward, I think you need to be checking for blockages.
Dave
M7040