Originally Posted by silver-man
The Fresh water tank is original and I imagine pretty spooky looking on the inside. There is a pump you can see in the pix -- I'm guessing it's a compressor. In any event these need to be replaced. I haven't been able to get the fill cap off -- continuing to soak the threads with Blaster. The PO really liked using this brown gooey stuff to plug any and every hole as you can see in the corner of the access door. The door itself is pretty beat up. Also there are 2 drains -- not sure why two? They have a stopcock -- is this what belongs?
Your trailer originally had a compressor but this is a demand pump. Your water tank is original & likely rusted out. Generic plastic water tanks are available at Vintage Trailer Supply.com & many other RV shops. The two drain lines you see are for the hot & cold water system.
Yes your trailer will need axles along with some degree of floor/chassis repair however this is common to all Vintage Airstreams.