I was under the impression that all hi hats had to have a way to access the j box. Usually I am able to remove the 3 screws and slide the can out of its frame, replacing it when I am finished. Yesterday I had one that was nearly impossible to remove. The only way it would come out was to pop the top off the cylinder. Then it was impossible to put back together. After an hour or so of cursing I finally gave up and had to go get a remodel can and replace the whole thing. I guess the access requirement was met, just no way to reinstall it. Is there a trick I don't know about? Was I supposed to push the cylinder up into the ceiling instead of pulling it down?
BigB

Maybe...maybe not...with so many different brands out there, it's hard to say what the "technique" is.

What brand was it?

I don't know the brand since they were coated with spray texture and paint, but I did another one today and pushed it upwards out of the frame, it was a piece of cake, looks like I've been a dummy and doing them wrong all along.

I tend to pull them down also. Sometimes you can't push them up. In a flat roof with blown in isulation where is the can going to go but down. I have only had this problem once before. It was a old model halo can.