Hardware cloth – something like ¼” square will work for the screen. Use “air conditioner foam” which you can also buy at the hardware store, open cell thin stuff. You can “activate” the charcoal by heating it up with your propane torch – outside the house – until the vapors cease to burn off.
If the hoses are not available from Moss or Victoria, use Gates green hose
Now back to the hardware store….. Purchase an expansion spring (s) that’s the same diameter as the hose. Hold one end of the spring in the vise and pull the other to permanently stretch the spring. As the spring extends, the diameter of the coils will reduce. Clip off what you need and insert it into the hose – sometimes a little grease or oil will help. Now you can tie the hose into a pretzel, if you wish, and it will never kink! Of course, it won’t have the nice fitted form of the original, but it will look pretty good and do the job.
I’m guessing that under bonnet pictures are available on the internet. If not, get back in touch with your year and model and I’ll see if I can come up with something for you.
SAFETY FAST!
John H Twist