I already have an awning on my trailer it's 10' and I'm looking to replace it with a 18' awning.  My question is can I use the existing arms (placing the one farther down on the side of the trailer) and hook up the awning to it or do I have to do replace them all?

The one I have now is an A&E and I'm either looking to replace it with another A&E or Carefree of Co.

Also - how do you fill the old screw holes on your trailer??????

As long as you stay with the A & E you could re-use the arms.

On the old holes; put some sealant in the hole and put the screw back in to fill it.