Neosakai

I tried searching for a solution to the clunking sound that people get with their coilovers and it seems like the common solution is to tighten the top strut nut to like 40lbs or whatever but mine doesnt seem to get tighten.

I can get it to the point where I cant move the nut with my hand but I can still spin it while holding a socket. I tried using an air impact wrench to ''tighten'' it but it just keeps spinning clockwise and it doesnt seem to ever get tight to lock in place and it just ends up having the stem (or whatever its called) show more threads as I keep spinning the nut in/downwards

Im also afraid it would just keep compressing the spring as I keep going on with it using an impact wrench or even by holding a socket and turning it or affect the ride height in any way making all the sides uneven if I just keep pushing the nut in but it doesnt seem to get tight

Can anyone shed some light on what Im doing wrong or whats going on lol

The coilovers I have on are Tein Flex sedan btw


Update: Seems like the shaft was spinning with the nut when I try to tighten it and thats why it never seems to get tight. I cant find a good way to hold the shaft in place while I turn the nut. Tried using an vice grip but the wrench just ends up slipping as I put force in the nut