Brakes grabbing in the rain

I usually just shift to neutral while stopping, for the first two or three normal stops after being damp-parked for a while. Doesn't have to be any sort of major production, the stops don't have to be especially hard or anything. If you have a passenger they probably won't notice what you're doing, unless they see you shift to neutral.

By disabling the powertrain regen braking, that forces the friction brakes to do enough work to rub off the rust quickly, and they'll be all quiet and non-grabby again.

Should be easy enough to do in a parking structure, if there's not a line of impatient drivers behind you. Or just put up with it until you're out on a street.

 

what condition are your brakes in?

when was the last time they had a thorough inspection and service?

 

You can also activate the friction brakes by pressing both the brake pedal and the accelerator pedal simultaneously. But be careful to not overheat the brakes, and don't do it if someone is following close behind you, because pressing the brake beyond a certain point will cut power suddenly.

 

That could well mean squat.

 

That's how drum brakes act when wet. Shoes have always been that way. It's the rears. Normal behavior for drums. Do nothing.

 

Or, if you prefer not to have them grab, you can do the simple something already covered above.

 

If it's the rear drums:

1. Place wheel chocks fore and aft of each front wheel.
2. Loosen lug nuts, jack up rear and settle onto safety stands.
3. Check rear wheels are near free-spinning, then remove.
4. Remove drums. They will likely not just pull off. In that case get a pair of M8x1.25 bolts, fully threaded, at least an inch long, and start screwing them into the threaded holes on the drums. Alternate turns, slowly screwing them in. If the holes are really rusted up, back them them out and blow out the dust, repeat. Eventually the drum should pop loose. Then wiggle waggle them off. It can take a while.
5. Remove the spring retaining clips, so the shoes are attached but loose.
6. Blow the dust out with a shop vac or leaf blower, compressed air, what have you. Do this outside if possible, and try not to breath it. Look everything over, drum inside face and diameter, shoe face and thickness, all springs look ok.
7. Put a dab of high-temp grease at each of the 3 contact points between shoe and backing plate. Use something like a knitting needle to get it in there, and be very careful not to get it on the shoe face.
8. Reinstall the spring retaining clips, drums.
9. Brush off the front face of the drum, apply a very thin coat of anti-seize compound. Just a few dabs with the anti-seize brush, then spread it around with an old tooth brush.
10. Install wheels, snug the bolts, lower car, torque bolts.

Attachment info for drum brakes assumes a full overhaul, which you're not doing, but just take what you need from it. Note they mention to put match mark on the drum and one stud, to install the same orientation.