Had to work on mine recently, the nut on one of the cylinders that holds the piston back off a little then it pulled the nut right off the shaft. M22 nut of course, had to drive to the big city to get that, took a thread file to the shaft, turned a recess into the piston so the new nut could get more good threads.
Thing opened and closed to fast, even had the pins in the cylinder ends a little bowed. Took the fittings out of the cylinder, tapped the ID, ran a bolt with red locktite in till they bottomed out, then drilled a 3/32 hole thru the bolt.