When a drum is turned, the radius changes. If the shoes aren't matched to the new diameter, it takes some time for everything to "wear in" for full contact between the linings and the drums. A good brake job used to include radius-grinding the linings to match the drum diameter, but the snowflakes with lace on their drawers these days would give a mechanic who creates any brake dust 30 days in the electric chair!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!