Drip rail sealer

[greasemonkey]

My sealer in the drip rail is cracked, peeling up, and the metal is rusting underneath. I know I can get the old sealer and the rust off now, but don't really know the steps to sealing the drip rail. I tried the search function, but there were too many conflicting opinions on brand of sealer. Do you prime the drip rail first, then apply sealer? Or is it apply sealer, and paint over top of it? Or can I apply sealer, and forget about paint (It doesn't have to look great, this is a temporary fix until I can afford a good paint job). Also, I need some sealer that dries fast, as my truck is a daily driver and never sees the garage; this would be an one day project. I just need to stop this neverending rusting that is going on in my drip rail, door bottoms and rockers.
Thanks for any help.
John