Will lubrication along the brake pad shoe rails solve an issue with the brake pads humming when being applied and backing up after a rain storm? (The brakes quiet back down after driving a short distance going forward)
Originally Posted by JTK
If anything, I would think putting some brake grease on the backs of the pads at the metal/metal contact points might help.
Certain types of friction material are more susceptible to moisture. No amount of grease will fix this. Glazing on the rotor surface can also be a contributing factor.
Another thing I've run in to: brake shoes/pads exposed to leaking brake fluid get very grabby when wet. They will chatter or lock up with minimal pedal pressure. Fixing the leak and using new pads/shoes is the fix there.