Tub faucet leaking inside

[SMRary]

Hi everyone... I have installed a new tub faucet and when we pull up the diverter for the shower, some water leaks from inside the faucet and comes out the base from the opening for the tightening screw. Any ideas what i can try ?? Here is a picture ..

 

[Terry]

Is that a slip spout with an O-Ring for sealing that tightens with an Allen wrench?
The copper needs to be smooth where the O-ring sets for it to seal.

 

[Sponsor]

 

[SMRary]

Is that a slip spout with an O-Ring for sealing that tightens with an Allen wrench?
The copper needs to be smooth where the O-ring sets for it to seal.

Yes it is .... thanks, I will give that a try