A guide to trailer brakes

Part of towing a caravan or trailer safely is ensuring that the braking systems are adequate.

Where the laws regarding braking systems are controlled by the state and may differ, most of the laws are the same across Australia.

Regulations say that trailers that have a gross trailer mass (GTM) of 750kg or less and a single axle will not require a braking system. Given that most caravans exceed this limit, it is likely a braking system is required for you to tow a van.

Trailers that are less than 2000kg GTM must have brakes that operate on at least one axle, and brakes other than override systems must be operated from the driver’s seat.

Car towing caravan in remote area

The type of braking system required is determined by a caravan's weight. Those braking systems include:

Override brakes

Mechanical override brakes use the tow coupling to manually pull a cable connected to the trailer’s brake drums. These are permitted when the GTM is under 2000kg.

Electronic brakes

They are automatically applied by the brake controller and can be manually operated by a manual control which is installed within reach of the driver. Electronic brakes are most commonly used on caravans and trailers over 750kg and are legally required on all caravans and trailers where the GTM is more than 2000kg. Remember that if you are considering electronic brakes, you will need to install a control unit in the tow vehicle.

Breakaway systems

These systems provide a way of automatically turning your caravan’s electronic brakes on in an emergency. If you caravan was to become uncoupled from the tow vehicle, a battery will keep the system operable on the caravan for at least 15 minutes. All states require that caravans and trailers with a GTM of more than 2000kg to have this system.

The weight of your caravan will also determine the number and type of safety chains required while towing:

  • Trailers that do not exceed an aggregate trailer mass (ATM) of 2500kg must have at least one safety chain fitted.
  • Trailers more than 2500kg and not exceeding 3500kg ATM must have two safety chains of 3500kg designation fitted.
  • Trailers more than 3500kg ATM must have two safety chains made from steel of a minimum 800MPa breaking stress. Each chain must be sized such that the minimum breaking load exceeds the ATM.