In Spite of Danger (1935)

Bill Crane, race-car driver has an accident while racing and finds himself unable to return to the fast-paced racetrack. Looking for another occupation he meets a girl, Sally Sullivan, who runs a roadside lunch-wagon and she helps him get a job as a truck driver. They fall in love and get married. He gets a contract to haul a load of dynamite and, when coming down a steep mountain, he finds his truck's brakes have been sabotaged, just as were the brakes on his race-car.