The most obvious thing is to give the brake a complete tune up. You might also try filing a slight chamfer on the leading edge of the shoes. The dust is toxic, take precautions.

Brake noises typically only appear when the brakes are applied. I'd be checking wheel bearings first.

► To test wheel bearings, put the bike on the center stand with the front wheel hoisted off the ground. You can put a scissor jack under the ex cross-over, or ask a young girl in a bikini to sit on the rear of the seat. (I usually have to settle for the jack, but hope springs eternal.) Sit on a milk crate or other low item with the axle pointed into your chest. Grab the tire at 2 positions 180° apart and do a slow, but powerful push-pull motion, yanking back and forth. You should detect absolutely zero play or movement. Any movement, noise or clunking (no matter how slight or tiny) means your wheel bearings have run dry and burned up. It is doubtful that adding grease now will restore the required fit. The damage has been done.

And if that's happening to the front, then the back can't be far behind... because wheels are typically serviced in pairs.

Wheel bearings are tapered roller type and need shimming (as well as greasing) on installation. This is a specialist job. It requires several measuring tools and an assortment of BMW shims.

► If you do open up the brake, Arni is correct. The first thing you do is garden hose off the drum AND the brake plate BUT NEVER the axle. (Washing the axle with a pressure washer is probably how your wheel bearings got in bad condition to begin with.) You may find a broken brake spring or such dragging inside the drum. The key again to effective repair is in "sets". If one spring has failed, then you replace BOTH. At 45 years of age, I'd replace both brake shoes no matter what. Believe me, you got your money's worth. Besides, new brake shoes are cheaper than a coffin.

Hope this helps.