Join Date: Jun 2017
Location: middle of nowhere
Take the floor out. Then look really closely at the undercarriage, supports, along the walls, etc. A lot of trailers that look ok are not ok because that rust is hidden. If it has visible rust along the seams, bottom of the trailer, etc. I would be very hesitant to use it. If you're at all concerned, take it to a trailer repair or manufacturing place and have them go over it for you. See if it's even worth fixing. Some are, some aren't. Some trailers need a new floor and new wiring and brakes and they're good to go. Others are not worth the expense of repair. Repairing the floor is easy and inexpensive. Its the supports and metal repair that can quickly add up.
Other things that will need to be replaced are tires (if the trailer has been sitting out in the weather, the tires are likely shot even if they look new), wiring, and brakes. You'll also want to have the wheel bearings repacked if it hasn't been done in the last year or two.