Hi, this is for my friend, he has a 77 caprice coupe he just got it out of his storage shed yesterday and when you are driving it it makes a loud ass grinding humming noise, sounds like from the rear left drum, but it only does it when you let off the gas, and only if you are going fast enough. and if you are coming to a stop it does it so much until you press the brakes in so far.
any help would be appreciated, thanks

Check the axle and axle bearing on that side if it only makes noise when you're at speed, coasting and not using the brakes.

he said it does it with the brakes too until you get under ten miles an hour, im thinking it has something to do with the drum setup on that side.