About 100%! All brake linings were asbestos until the 1980's or later, and I don't know any mechanics who have developed asbestosis from working around brakes. Now, if your job is grinding brake shoes 8 hours a day for the past 30 years, you might have a concern, but simply handling asbestos-base brake shoes every few thousand miles on your own vehicle is a lot less dangerous than standing on a golf course waving a metal club around, if there's a cloud anywhere in the sky! Don't sweat it!
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!