[tetra]

Here's a response from jetrinka on FF about the spinning:

"If those nuts aren't tightened down all the way you will for sure get a clunking sound as the spring moves in its seat. I am not sure about the Ford racing style but most others have some sort of allen key or something on the very top part of the piston that the nut threads onto. Get the correct holding tool such as an allen if thats what fits it and use an offset wrench to turn the nut down while holding that piston still.

If there isn't any hole for a holding tool to go into then your going to have to figure out a way to hold that top part of the piston still while you turn that nut down like the vice grips you were using. That nut must bottom out on its threads for this problem not to happen. Only then is it properly installed.

And no the piston turning while you try to tighten it is not a bad thing. Totally normal. Just find a way to hold it still while you turn that nut all the way down and your problem will be solved. "