D2 13XXX Hyd Cyl 8F2657

Never have seen a torque chart for hydraulic piston rod nuts. I just get them as tight as you can....I clamp mine in my big hydraulic press and swing on the end of a 5-6 ft cheater on the breaker bar or rattle away with the one inch drive hydraulic impact wrench. Don't forget the lock tabs.

I don't recognize that number....is it a casting number or part number?

Old Magnet
That is the casting number. I also have a set of old style cyl that have a hex nut. I tightened them as tight as I could. The newer style have a diffrent type nut. It is round with 2 flats cut in it and don't provide much to get ahold of, locked with a cotter key. The piston is long with three composit rings that install like a engine piston ring. The piston is prevented from rotating by a key. The by-pass is controled with 2 valves built into the piston. Is it possable that the piston is designed to float?

That would be this style of cylinder.....see what you mean on the retainer nut....about the only way you'd get a good grip on the two flats would be a special socket. I wonder if it could be replaced with a conventional hex or jamb nut and cotter pin.

Not sure what you mean by float......if on the rod, no.....in the cylinder, yes.