Hi-
I was hoping someone could help me with a somewhat basic plumbing
question.

I am replacing the valve stems for my shower (3 handle set-up).

As part of this I want to replace the the brass bushing that the valve
stem presses into (not sure if I am using the right terms); the stems
I bought from Lowe's came with new bushings.
I was able to remove the old bushing, but the new bushing (that came
with the stem that I bought) would not screw into the old seat.
Upon inspection, it appears that the threaded section of the new
bushing was half that of the old section.
Not sure if this was why the new bushing would not screw in, but it is
driving me nuts.

Has anyone had this problem before?
Any ideas how to address this?

Thanks
Sue