I've heard that once a rivet rust on an aluminum trailer forget it.
Rust will spread like wildfire.

This is a terrible situation. If a rivet rusts, it is iron or steel.
An iron bearing rivet in aluminum is just begging for dissimilar metal
corrosion.... big trouble.

Have you ever seen a steel rivet on an aluminum trailer? Can't say that I have
and I've had at least 5 aluminum trailers that I can think of.. Any steel parts
that I can remember were galvanized and fastened with galvanized bolts. I don't
ever remember rust being a problem on the main frames of aluminum trailers. The
springs and spring connectors and the axles maybe. All are parts that are
generally considered replacement parts.

Barry