hansgrohe shower diverter assembly leaking water behind wall when showering

[Aaronac8]

Water is getting behind my hansgrohe shower diverter when showering. Please see attached pictures. Does the top 2/3 of the shower diverter cover need to be silicone caulked to the shower wall? Is there a gasket that needs replacing? Red arrows point to where someone tried to silicone around screws to prevent water from getting behind the diverter....needless to say, that did not work. Any advise would be greatly appreciated. Thanks.

 

[Aaronac8]

I figured out the model number:
hansgrohe model 1000697999

I found out how the water is getting into the wall. There is a gap under the valve assembly (see red arrow below):

And whoever installed the valve did not use the installation box:


Also the gasket has a space where water can get behind the tile (see green arrow):

This is the diagram of the fully assembled valve:

Any suggestions on how to fix this problem without tearing the tile down? I was thinking that I could close the inferior gap in the tile with some Bondo and a fiberglass mat, so the gasket will not have a gap.

 

[Geofd]

I have caulked shower valve plates before when this was an issue, you can make it look good just be patient

 

[Tim Whistler]

Just caulk the trim plate to the tile, maybe use a couple of balls of plumbers putty between the trim plate and the valve down at the bottom to cover the internal gap a little bit.
For this I'd use straight 100% silicone and mineral spirits on a sponge to 'wipe' it so it looks good.
As long as there not an actual, visible gap between the trim plate and the tile this should be fine.
-Tim Whistler

 

[Aaronac8]

This screw will not budge. (Red arrow below). Suggestions on how to loosen it? Thanks.

 

[Geofd]

This screw will not budge. (Red arrow below). Suggestions on how to loosen it? Thanks.
View attachment 36968

Tap the butt of the screwdriver with a hammer sometimes shocking it can help or a little pb blaster wd-40