a '68 Caravel
is built the same as a '68GT, Then, here's what I know…
All 1968s have 4” frame… Caravel
frame is 3”
was the year of sprayed closed-cell foam floor insulation. The foam is generally 2” thick, but varies. No fiberglass batting in floor.
has 5/8” filled-void plywood floor.
Along the outside perimeter, the plywood floor is sandwiched between a simple, true U-Channel (different than the F-C channel common to seventies trailers) and the tips of the outriggers with Elevator Bolts.
The streetside and curbside exterior skin panels are attached to the U-Channel. Then, they wrap under the trailer, and capture the bellypan.
Drill out the pop-rivets along the edge, Do not drill buck rivets. Then, the side skin will drape downward giving you excellent view of frame, floor, outriggers, foam insulation, and inside bellyskin. Nuts and nests can be easily vacuumed or blown out with air, there is no insulation in the way. The insulation is adhered to plywood.
The draping sideskin will give you access to the outrigger's elevator bolts where you might replace floor.
On my trailer, anywhere the foam adhered to the steel, the frame was in like new condition. Areas that had no foam, were light surface rust. The closed cell foam was very protective of the plywood too. No oxidation. The foam cannot wick or saturate with water. I know this because I submerged a chunk in my pond for a week, and it bobbed up, dry.
It's common for outriggers to poke through. Could be frame issues, but most likely wrapped too tightly when assembled in 1968
. When the sideskin is detached and draping, you can easily adhere an inside patch at the outrigger's edge, or better
“My question is, would it be wise to make a skill saw cut and remove about a 1 foot wide section of subfloor on both sides over the main frame rails to see if any have rusted away or separated so that they can be welded from on top to avoid pulling the belly skin.”
Unwise and unnecessary.
You can reach much area and inspect from below. It's clean and easy, I found no deteriorated foam dust, or foam chunks… Dropping entire pan will become necessary if frame damage is suspected or found.
It's pretty strait forward on a 68GT, Caravel...?? Hopefully