Question If hydraulic brakes fail, a driver can reduce their speed by: Answers Shifting into a higher gear. Shifting into a lower gear. Finding a hill. Letting the truck run out of gas. Explanation If your hydraulic bakes fail, shifting into a lower gear can help slow your vehicle down. Take a FREE Practice Test Now This questions appears in the following tests: West Virginia Knowledge Test Class A , South Carolina Knowledge Test Class B , Texas Knowledge Test Class B , Connecticut Double ,