Young Pup:
Not a young pup ... but I'll give it a try!

I presume the slider screws in/out.
Yes
Is there a sealant that goes on the threads?
Yes. Many people have used blue lock tite with success.
How did you spin it in without warping the new slider?
There is a hole at the top of the tube. Slide a large screwdriver through this hole and start turning.
