2000 beetle stalls

my 2000 1.8 turbo beetle stalls when braking, this happens sporadically multiple visits to the dealer and not fixed yet any ideas on what is wrong. the diagnostics is cleared

Sounds like the brake booster mechanical vacuum pump. Its a valve under the intake manifold that routes engine vacuum to the brake booster. It allows the use of power brakes. If your pedal is really stiff I'l have them check that out. Since its a 00 and a 1.8t I can almost guarantee that all the breather hoses and vacuum lines under the intake a cracked and broken.. its about 450.00 in parts..