The neck is more bent. He said he would cut it off and weld a new neck/coupler on it that is heavy duty. I just want to make sure it is done right and not butchered.
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I build trailers as well as repair them.
That kind of "amateur operator" jacknife damage on that kind of trailer design is not easily repairable
with the exception of the coupler itself;
that can obviously be replaced.
That "he" suggested anything other than simply removing and replacing the existing "A" coupler with an identical one raises questions immediately as to the competency of "he".
The C-channels that make up the A frame of the tongue are bent and twisted.
You'll just have to live with that unless you want to have them replaced completely; all the way back to where they end on the cross-frame. Since its a single-axle trailer, the residual misalignment you'll have after coupler replacement should be of little consequence.