[VWNate1]

The why not , is because , even if the drum is still within spec. , it's too thin and will overheat & fade during towing or emergency stops .

I learned this when I took my Journeyman Bendix Factory Training , before then I too automatically turned all drums then I learned it's a B. S. sales gimmick to sell more drums .

What the Bendix Engineer said was : unless the drum is so severely out of round that you feel the brake pedal pulsate , or if it is so severely bell mouthed that the shoes wore un evenly to the side , the drum MUST NOT BE TURNED for basic safety reasons .

Sort of like changing the condenser every time you replace the points because " the condenser takes a ' burn ' to the points " ~ TOTAL BULL CRAP ! the only reasons to change condensers is failure (rare) or if the points are unevenly pitted ~ once in a while you'll get evenly pitted contact points and that condnser is -GOLD- NEVER replace it and your points will last 4 X longer .

But , you say ' what about when the shoes went metal to metal and the surface is all torn up ? ' ~ just sand it a bit with # 600 grit (coarse) sand paper and as long as the drum isn't over sized , run it ~ the new brake shoes will bed into the rough drum surface in 10 miles and be fine .