Water Pump - need help identifying screws used to anchor the system

[Boudicca908]

Can anyone help me identify the TYPE and SIZE of screws to anchor the lines around the Water Pump?  I have found several of these are missing (see photos attached), and am loathe to take any out, because I'm not sure whether I can re-install them by hand OR whether they will stay in place, if mounted into the existing holes.  I'm on the road (not at home) and haven't been able to find a hardware where I can pull in with my trailer in tow to get help with this. 

I don't have power tools, so am limited to using the standard screwdrivers. 

Does anyone have suggestions or solutions:

- alternative mounting (screws of different size, addition of some kind of glue, or different system to hold them down)

- how to size screws (in general) without removing them 

Is this standard (another thing to add to the list for pre-trip maintenance)? 

I have inquired at OTT mothership (I discovered them missing right after my maintenance service). They have not been able to assist with identifying the screws used, nor suggesting methods to reinstall or what to use in place of original anchors.  EDIT: ** They did suggest that I could "try gorilla epoxy" to see if it would help (once I find the right size and type of screws to use, one would assume).**

 

Edited 2 hours ago by Boudicca908
added info

[mossemi]

@Boudicca908

The man made mounting material or as I refer to as PVC, does not hold screws or threaded fasteners very well when using the same size fasteners as were original installed.  I would suggest removing one of the existing screws and then finding the same type of screw that is one size larger.  I think they are common pan head screws and installation and removal can be accomplished with a Phillips screwdriver.  Some type of adhesive may help, but anything like epoxy may make removal difficult.  So if you do use an adhesive, use it sparingly.  You can always add more the next time.  
 

Mossey