How do wheel brakes work?

The brake system on a trailer consists of three parts:

  • Overrun brake
  • Brake transference
  • Wheel brakes

The overrun brake is attached to the car via the coupling head. The coupling head is located in a tube that can move forwards and backwards so that when the brakes are applied on the car the coupling is pushed together. The coupling and wheel brakes are joined via the brake transference. The force from the tube in the coupling is transferred to the wheel brakes via cables and rods.

The two most important parts of the wheel brake are the brake drum and the brake shoes. The brake drum is screwed to the wheel, and rotates around the hub. On account of the wheel bearings, friction is low and the wheels roll easily. The brake shoes and fixed to the brake anchor plate, and when the brake mechanism is activated the brake shoes are pushed towards the inside of the brake drum. This results in friction between the brake drum and the brake shoes, so that the speed of the trailer decreases.

The brake mechanism is activated when the brake cable pulls in the expander, which in turn moves the brake shoes.


Vad händer när bilen bromsar?
The diagram shows what happens when the car brakes

Can I change this myself?

As a private individual, you can change this yourself, if you feel you have the ability to work on your car and trailer. We have collected valuable information on our website that you can use when repairing your trailer. We have also posted instructional videos about how things work.

At Valeryd we advise if you are uncertain you should seek out a garage that can help you, or if you know someone who can help you.