It’s easy to check the internal leakage. Apply the hydraulic pressure first, after 15 minutes, if there is oil inlet and return through the cavity, the return pipe will be very hot!
First push down the valve head of the change-over valve with a screwdriver to see if there is any change-over action to eliminate mechanical reasons.
There is also a power inlet valve of the press brake machine, which is from high pressure to low pressure.
Check out its pressure.
The mechanical reason is eliminated, and the rest is the problem of the valve group.
