DIY Doctor UK DIY Forums

I was cleaning the bath tub and I had unscrew a cap from the side of bath tub (where the hole is located) below:
https://i.stack.imgur.com/74Uwf.jpg
[![Whole bath tub][1]][1]

The cap consists of 2 parts:Part A & B as below
https://i.stack.imgur.com/Bxn2Q.jpg
[![part A & B for cap][2]][2]

When I removed part B, there was a screw at the part A to hold the part B.
Here are the layout diagrams:
https://i.stack.imgur.com/VLx6F.jpg
[![top view of part a with screw and part b][3]][3]

Here is the top view of part A with screw
https://i.stack.imgur.com/QB7c9.jpg
[![top view of part A with screw][4]][4]

Lastly, based on my best guess & screw type/size here is the back of the part A with screw. Take note that the white part of the part A would be glued to the bath tub wall
https://i.stack.imgur.com/sKLO7.jpg
[![back of the part A with screw][5]][5]

However, by accident, I had pushed the screw into the inner part of bath tub.

1) Would there be any problem if I left the screw inside the bath tub?
2) The part A is held on the bath tub wall by a glue. What glue should I use to stick the part A on the hole? This is how I stick part A on the bath tub:
https://i.stack.imgur.com/dYzvr.jpg
[![how to place part A to bath tub][6]][6]
3) What screw, nut, bolt or other tool to hold part B to part A?
https://i.stack.imgur.com/VvDUa.jpg
[![how to put part B to A][7]][7]

Any suggestion is welcomed! Let me know if you need more photos! Thank you.

**EDITED**

Further investigation reveals that there is a bath tub drain system installed in this bath tub, as seen in the image below:
https://i.stack.imgur.com/mSqxB.jpg
[![Bath tub drain installed][8]][8]

This is the best I could do to get bath tub drain system out to the wall of bath tub, while waiting for a solution from you all on which glue to buy.
https://i.stack.imgur.com/BFhFo.jpg
[![enter image description here][9]][9]

So only question remains now:
How to join part A, part B to the bath tub drain system behind of the bath tub?
What glue should I use to hold the bath tub drain system to the bath tub wall?
Thank you.

Hi hunterex
Your best option is to retrieve the screw which, with luck, will still be in the overflow pipe. You need sanitary silicone to seal both sides of the overflow.
Regards S