My husband changed the shower stem of both hot and cold faucets and the cold stem fits fine but the hot won't stay in tight enough and when you put the water on the pressure shoots the stem out. What do we do and wh is this happening?
Thank you

First thing, I would have to know what brand of faucet you have or at least what the stem looks like, and a little description of the faucet. If he has a camera he might take a picture of the stem and faucet and add it to the post.

Look at the shower valve I've put up. On the stem you will see a small nut, (the bonnet packing nut) with a bigger nut underneath. The big nut is the retraining nut. This is the nut that holds in the stem. If your valve's different let me know the brand name and its age. Good luck, Tom