Use of brakes
Apply steady pressure at the beginning of a stop, then ease off as the vehicle slows. Just before the vehicle comes to a complete stop, release the brakes enough to avoid a jerk and rebound, then apply the brakes again to hold the vehicle while stopped. See details on the use of Hydraulics and Anti Lock Braking Systems (ABS).
You should not fan your brakes (alternately apply and release them) except on slippery pavement where this type of braking (also called threshold braking) gives better control, reduces danger of skidding and gives a shorter stop. Fanning reduces air pressure and serves no useful purpose on dry pavement, and fanning on a long downhill grade may reduce air pressure below the minimum pressure needed for proper brake operation.
Take great care to avoid excessive use of brakes on long downgrades, as overheated brakes are dangerously inefficient. Use engine braking as the principal means of controlling speed on long grades. If possible, you should use the same gear in descending a long grade as you would climbing it. Make your gear selection before descending a grade to minimize the chance of missing a shift.
If the low air-pressure warning device operates at anytime, stop immediately in the safest available place and correct the loss of air pressure before proceeding.
If brakes should fail on a level road, you should downshift and use engine braking to slow the vehicle. If a shorter stopping distance is necessary, use the tractor and trailer emergency brakes, if fitted, to stop. You should not drive the vehicle again until repairs have been made.
In a combination of vehicles such as a truck-tractor and semi-trailer, trailer brakes are applied with the truck brakes using the foot control valve. This is known as balanced braking. The pressure applied on both the trailer and the truck-tractor brakes is the same. Trailer brakes may be applied independently by using the trailer hand valve. Pulling harder on the hand valve may increase the amount of pressure on the trailer brakes during a foot valve application.
Exercise care in braking a combination of vehicles on wet or slippery surfaces, or on a curve. Over-braking in these circumstances can result in skidding or jackknifing. If the tractor is jackknifing (if the tractor rear wheels slide sideways) apply the trailer brakes only. If the trailer rear wheels slide sideways, release all brakes and gradually apply the accelerator.
Spring brakes are designed to work when you are parking your vehicle or in an emergency when your service brakes fail. They apply automatically when the air pressure in the system drops below a predetermined level (normally 414 kPa or 60 psi).
Note: If you plan to operate a vehicle equipped with air brakes, refer to The Official MTO Air Brake Handbook for further information.
Note: Some municipalities may have restrictions on engine braking. Ensure that you follow the restriction signs in each municipality.