How old is the trailerand in what condition is ith axle
Old trailers with "dead" axles have seen lots of shock loading on the frame and many have cracked and broken frames in the front under the floor ahead of the door.
The frames crack where the sheetmetal screws go into the frame and the weldments where the dropped door section ties into the right front of the frame.
Also weak points are where the frams is bent to an angle to meet at the hitch.
This is especially true for the earlier 14 gauge rectangular tubibg before the change to the 11 Gauge.
My 1985 was cracked in many spots and had been poorly repairs several times.
I am cutting all of this out and replaceing with the 11 Gauge (1/8") tubibg and adding the lower frame 3" X 1 1/2" part doubler as well.
I have not decided yet but I think I will aslo reinforce the rear as well wioth some tapered sections from the center 6" part to the rear bumper so that I can jack the thing where ever I want.
This will add to the weight
, but it should then last for the rest of my days!
While I am in there I am also replacing that 30 year old axle with a new one.