Frozen brakes 2005 nissan

brakes
#1

we have a 2005 nissan altima 3.5v6 auto. we live in New Hampshire and on cold days anything below 20 f . the brakes will be frozen on the frist time we drive the car in the AM. we bought it used and this is our first winter with it. the brake pedal will not move. it seems to help if we let the car warm up, but it still happens. if we let the car sit all day at work it will happen agian. but it has to sit hours and really cold for it to do it