Hydraulic workshop press ram wont return 2

[metalbasher]

Hi all we have just brought a manual VL Churchill 40 ton hydraulic press, after filling it with oil I pumped the ram down and it came down ok but i can not seem to get it to go back up.I have opened the valve handle but there is no movement in the ram.There is a pic of the press attached.If anybody can help that would be great.
thanks metalbasher

 

[btrueblood]

See the tube running to the bottom of the cylinder? You need to pump fluid through that tube (and vent fluid from the top tube) to push the rod (ram) back up.

 

[arunmrao]

If the connections are correct and there is no clogging of the valves, you may consider bleeding some oil to check if there is any air lock in the system. quite often in a closed loop system this could pose a problem.

Chocolates,men,coffee: are somethings liked better rich!!
(noticed in a coffee shop)

 

[limey1]

Agree with arunmrao. When you open the release valve, fluid should return to tank and bottom pipe should be pressurised and send ram back to home position. Unless there is air in system

 

[griffengm]

Metalbasher,
My Dake press will often not return without a load if it has been a while since I used it. The only way I have found to overcome no-retract is to run the ram all the way out, clean it thoroughly and give the ram a coat of light oil. Since mine has a ram screw, I extend it to get some pressure. I can either release the pressure and let the ram retract on its own or, failing that, leave the release screw open and further extend the adjusting screw which will force the ram back. Sometimes, like when the bed is too low for the adjusting screw to contact, I have used a pry bar to force the ram back. I suspect this is what you will need to do.
I believe most of these manual cylinders are single acting and use an internal spring to return the ram (like a small bottle jack). Dirt, rust and cold oil will conspire to limit the return of the ram.
Griffy