Repair hymer insulation by injecting foam from hinge screw hole?

[adma]

Hello and thank you all for the valuable information I've stumbled upon over the years !

I have a '92 hymer camp 55 where the structure is a sandwich of two aluminium plates with PU foam in between.
The screws that hold the lower part of the door keep coming loose, and upon further inspection there is some light softness around the door frame.
I do not know if that is a recent damage, but to be sure I have resealed everything on the outside.

I would like to inject something from the hole of the door screw, and I see some options:

1) PU foam : might expand too much and stress/bulge the frame ?
2) Low expansion PU foam : the door screws won't be able to hold on to it for too long ?
3) epoxy : maybe the heat produced during curing will mess something up ?

Are you aware of any product that I could use ? Something that is sufficiently runny to flow into the nooks and crannies, or expanding but not too much, and that ideally it would also hold the screws. See the attached photo (not mine, but to get an idea). It is those screws that come loose, from which I would like to inject something.

Thanks !

 

[Rollingwheels]

Might be worth looking at a tube of cartridge pu adhesive as it doesn’t expand too much and has a bit of resilience to it you could also push a plug of some plastic dowel in after pumping in so the adhesive adheres to the dowel for a good screw fixing

Everbuild Lumberjack 5 Minute Polyurethane Wood Adhesive Gel, Transparent, 310 ml​

 

[adma]

That is a good idea, thanks.
I am flirting with the thought of cutting through the inner part of the shell to slide in a metal block on which I can screw the hinges.
It will probably be much more long lasting, but also more work to make the repair imperceivable..