The problem is these fasco contactors keep vibrating and make alot of noise, the parts house guy told me to hit the contactor to get the armature back in line again (after replacing the two which run simultaneously) and quiet them down.....but just am not in mind set that a "BFH" is the answer.
I think what might have happened here is that there may be some dirt or grit stuck between the pole pieces of the armature in the contactor.
If the two parts of the armature don't fit together squarely, there will be vibration as the side with the gap in it tries to pull the armature closer.
My advice would be to dismantle the contactor and check it, and if necessary give the pole faces abit of a rub with some fine abrasive paper, not too much though, the pole faces need to be clean and smooth.
Hope this helps.
Edit: I would get any advice like that given by the supply store guy in writing before actually taking to a contactor like that, thier returns policy may be a tad different with a broken contactor.