Tub Delta faucet leak - How to fill space at wall?

For years my tub faucet has leaked; never paid much attention to it. Now I find that it was not only leaking into the tub (why I procrastinated), but also into the wall and the living room ceiling below.

I have the parts to fix it. After I take the swivel handle off, there is a sleeve about 1.5" in diameter and about 2" long. The drip was getting into this sleeve and then into the opening in the wall where the hot and cold water come into the back of the handle and go out a common pipe to the shower head.

While I am fixing the drip, I would like to fill this space with something so that if the faucet leaks again, it will not leak into the wall.

What is the best way to fill this space? Is there a rubber part I can place there to close this gap, or ??

thanks

For it to leak into that sleeve the leak must have gotten pretty bad! Next time don't procrastinate!

Agree - lesson learned!

Any suggestions on the question though?

Yea just what I said. Usually the leak doesn't get under that sleeve. Usually most will drip out from under the handle. That is why I said you must have allowed it to get very bad.

I take it that the sleeve slides through the face plate and the leak was between the two? Most of the time there is a foam gasket on the face plate that seals against the sleeve. You might try to put the sleeve and face plate back on and mark the location of the face plate where it ends up on the sleeve and take it back apart and apply some clear silicon up to the line you marked and reinstall. Clean off any that makes it past the face plate.

Just seen Redwood's post to another topic here and if I may, does it look like this.............

http://www.deltafaucet.com/media/Product_Tech_Docs/Parts_Diagram/Models_622_635_636_641_642_5985.pdf

Right and if the water was leaking back through the tube under the handle you had a very bad leak that you should not have procrastinated on. Water normally will not go back in this direction therefore additional sealing is unneccessary.

Yes that would be one heck of a leak and for some time too.