Good morning Loren G. Hedahl;
I'd suggest that you go back to bed and rethink this idea.
Personally I wouldn't attempt this while the axle is under the trailer.
Ever seen a burning rubber tire pile? Imagine all that black sooty mess curling around the sides of the trailer and make soot tracks all over the place. I wonder how long the smell would linger?
If it starts the trailer on fire, how do you put it out- burning rubber isn't the easiest to extinguish.
What kind of active suspension will you be getting with the RTV rubber when cured? Will the resultant suspension be even on both sides?
How long will it last? If your trailer starts to sway, oscillate, or whatever, will the resultant motion be enough to .....
Applying heat to the axle/bearing area, what could happen to your bearings? Any wiring, piping etc in the area?
If you have electric
brakes that just adds to the mess.
I'd suggest spending the time, effort and money installing a new axlecomplete with
brakes.
The last axle was in there since 1984, the new one will last longer than you probably will have the trailer. Plus its a selling feature.
Wayne