Brake groan

[TopherS]

I've had this problem for a while now, but don't quite know what it's from.

When it is cold outside and raining (as it always does here) and I am backing up, the brakes will groan very loud (for instance, backing out of the garage/driveway, they will groan the whole way down). No groaning in forward motion, only reverse. Last time I had the brakes checked (and it was doing it then, too), they were at 50%+. There seems to be no loss in stopping power, no fade, etc. Only noise in reverse. And the noise is not the squeal of the wear indicators, but a groan.

Any ideas?

[HotZ28]

but nothing unusual here! This is a normal sound reaction to a glazed pad on a moist & rusty caliper.