Replacing a tub drain assembly

Hi. I am attempting to replace a lift and turn tub drain replacement assembly. When I screw it it goes in crooked and does not screw far enough in to be flush with the tub...perhaps i need a little more strength! ha! I have the old one out and tried to simply screw the new one back it. It looks like plumbers putty (?) was used to install the previous one. Do I need to use it for this new one? Do I need to remove old putty? HELP!! Thanks for any advice.

Remove the old plumber's putty and use fresh plumber's putty under the new drain flange. Use this tool ("smart dumbell") along with a large crescent wrench to tighten it up, and don't cross-thread it.

If the new one is plastic be carefull not to X thread it while attempting to install it.

You also don't need 400#s of putty, just enough to seal between tub and part being installed. If you use to much you may end up with a leak down the road.

When doing this replacement, do you also need to replace the washer between the drain pipe and the tub? (if so, can this typically be done from the top side, by pressing the drain down a bit and wedging the washer in?)

Thanks,
Matt

YOu can do it from the top, but be careful, if you drop it or it slides where you can't access it, then you'll need another one, or tear things out. Maybe slide something in the pipe to keep it from straying? I've only done a few, and they went okay.