The hydraulic seals need replacing on this cylinder.
It is said to be 10 Tonnes-force capacity.
It extends when pumped and is only returned by a force applied to push the piston back into the body.
Size - scale:
all steels of the "U" is 100mm x 50mm Rectangular Hollow Section
"box". So the thickness / depth / width seen is 50mm.
The cylinder body is slightly larger diameter than 50mm.
The open gap between the "parallel U" inner faces is 135mm in the
first picture (in the second picture the "U frame" is significantly
deformed).
So that 135mm in the first picture is the current length of the
cylinder and piston.
(R. Smith, 04Dec2020)