I have the shock absorber and spring off and have swaped the shock with the new one. I now need to tighten up the top retaining nut but the shock absorber piston rod just turns with the nut. How are you supposed to do this? Is there a special tool?

At the very top of the shock piston there is a flattened bit with which you can turn/hold the piston with, but you can't turn the nut and hold this at the same time.

The spring is not compressed enough to get the piston into a vice to hold it from rotating.

Any ideas???

The retaining nut came off okay because I think it was stiff from not having been undone for a while and it held just enough for me to get it undone.

Thanks