How to properly re-bend side rods?

If that is anything like my brass engines I place soft copper jaws in a vise and gently unbend them  on two different planes. Then when kinda flat and straight I place them in a much larger vise with soft jaws and muscle them ham fisted flat.  Worked fine for me. 

Probably best to wait for others to chime in who have worked with MTH rods.

I would be reluctant to apply heat if you are not familiar with the properties of your rod and heat ranges needed.

That piece is likely plated brass. Your father is right. It will bend easier with heat, if you have a hot air gun that would be best. If you have to use a torch hold it back far enough so you don't discolor the plating.  Just get it too hot to touch (fry spit). Then just bend it back slowly. You will likely have to use smooth jaw pliers or a small vise to get the small kinks out.

Pete

No heat is needed. If anything, it will discolor the plating. That rod can be 98% straightened with a pair of pliers. Put the rod between 2 pieces of cardboard so not to mar the finish. It is soft enough it will bend back and not snap.

@Chuck Sartor posted:

No heat is needed. If anything, it will discolor the plating. That rod can be 98% straightened with a pair of pliers. Put the rod between 2 pieces of cardboard so not to mar the finish. It is soft enough it will bend back and not snap.

I've never used heat .         I have taken two pairs of fine needle nose pliers with small pieces of adhesive back tape applied to the jaws.      Be careful to hold the rod down from the bolt head connection so as to keep that area of the rod flat.        Never had any problem with the rods except when picking the steamers up pressing on the rods..😶🙃

Happy Holiday all .

"Then just bend it back slowly."

This may be the most important thing when re-shaping a damaged metal part: patience. Little bit at a time.