Grohe Parkfield, leaking tub spout help

[Antsy]

Hi looking for some help. I am a homeowner. The tub spout in our tub/shower combo is leaking out the bottom. We took the tub spout off to have a look. What is usually the cause of this? I've included some pictures. We cleaned up all the silicone, cleaned up the black ring and put it where it should have been. We bought a new o-ring and installed it on the stub but we don't think it is the correct size. We put the tub spout back on and it still leaks but not as much. Is the stub that sticks out of the wall replaceable and is it specific to the brand of faucet? Could this be the problem?

We were able to look at the back of the plumbing behind the wall. When the house was built 4 years ago plumber installed the valve backwards and they had to go through the wall in the closet to fix. I had them leave an access panel for future repairs. There was no leaking from any of the plumbing in there.

Just looking for ideas on what could be the problem.

Thanks for any help.

 

[Marlinman]

This is Grohe Parkfield. Click on installation sheet for the part numbers for your spout.

https://www.grohe.us/Bath-Shower-Tr...-Valve-Tub-Shower-Combo/GROHE-CHROME-35040000

 

[Sponsor]

 

[Antsy]

Thanks Marlinman. The problem is I have no clue what part could be the problem.

 

[Marlinman]

I would replace 45735. This is the diverter portion of the spout.

 

[Tuttles Revenge]

Probably wouldn't hurt to replace that o-ring on the brass nipple at the wall either while you're at it.