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.
