My guess is, without seeing a photo of the frame & cylinder, that there is some grit, dirt or some foreign substance inside the crane area, which is preventing the cylinder/yoke/crane assy from swinging out and down completely. If that is the case, you'd need to remove the crane from the frame to clean out the area. However, you might first want to just try flushing the area (before any disassembly) with a solvent or spray lubricant....then working the cylinder/crane assy in and out of the frame repeatedly.
Let us know what you find.