I've finally got both of my struts installed and the car back on the ground. I'm trying to tighten the top nuts of the struts.Why on earth would the top nut be extremely hard to thread onto the brand new strut?

Strut/nut was difficult from about the 2nd thread, and continues to require more force the further I tighten it down. I am to the point that I'm afraid I'm going to break something. I got it to within 1/4" of being seated properly on the bearing plate. I backed it off a little while later to check everything out-- the nut was too hot to hold just from the friction of REMOVAL. What's the deal? Both sides are equally difficult to tighten.

 

Chances are that it isn't tightening and getting hard to turn, but rather....The strut shaft is spinning & turning with the nut.

 

The shaft isn't turning, I've got ahold of the nut with a wrench/cheater bar and a socket/ratchet on the 10mm hex head of the strut itself.

 

OK......

Wrong sized nut then? Maybe the manufacturer made the new struts with the wrong thread size, just a hair off? Maybe standard vs metric? Or are these the nuts that came with the struts?

 

this

you may have received the wrong nuts.

 

Are they nylon-lined nuts?

 

They are indeed the nuts that came with the struts in the box, no they aren't nylon lined

 

that still doesnt mean they are right. if they are getting tight after a thread or two, they are the wrong thread pitch. do the old ones fit?