Some of the rusr removers/converters I have used are:
Naval jelly
Evapo Rust
Eastwoods Fast etch
Eastwoods rust converter
Permatex(loctite) Rust Detroyer
Picklex
I used Eastwoods Bloxide for a weld thru primer. I liked it because you can apply it right where you want it. It has aluminum in it and protects metal for many months. It needs to be applied to clean metal though. The Evapo rust is really good too, but it does not offer long term protection. The Picklex is a very good rust remover/converter, and can be welded thru, except you cannot use it with self etching primer.
I also used Rust Bullet on places where I could not replace metal, or metal that was deeply pitted. It is 4 years now and seems fine.
Hope this helps.