Seeking recommendations - New heater blower motor

I have found that if you put on multiple coats of primer you can fill any small pits and after letting it thoroughly dry, you can sand it smooth with 320 grit sandpaper. For deep pits after cleaning it out, you can fill those with a little JB weld using a razor blade as a squeegie.

I should have mentioned this before but just forgot. What works well in this instance to clean the rust off the steel motor cases is a plastic bucket and some straight vinegar. Clean off any grease or oil from the motor halves, then drop the motor halves in the vinegar fully submerged. Periodically check on them. The acid in the vinegar will dissolve the rust.

Rinse the parts thoroughly in a bucket of water that has some tridodium phosphate TSP mixed in it. You can buy a box of TSP at lowes or home depot in the paint section for about $5. Doing this with the water and TSP mixture will allow the parts to dry without flash rusting.

I would recommend after repainting to coat the insides of the motor cans with a light coating of machine oil wiped on with a paper towel to prevent rust in the future.