Brake roller test

The brake roller tester is used to measure the braking force of a vehicle. The  machine we used also tested the shock absorbers. First we drove the vehicle onto the shock absorber tester and the machine tests them then we moved the vehicle's front wheels onto the brake roller tester and applied the brakes according to how much the machine specified and once the test are done we applied the brakes hard. Then we tested the back  shock absorbers, the back brakes and the hand brake using the same procedures.

We discovered that the left wheel failed on the park brake test. The vehicle that we tested had inboard brake drums for the park brake so it narrows the problem down to the drums. It could either be the brake shoes, the handbrake cable that is jammed up or the adjustment of the spreader. In our case the shoes still had enough lining on and the cable was not jammed so it is probably the adjustment of the spreader.

If a vehicle with only drums or only rotors was tested and the back brakes are fine but the park brake is not it is more than likely the park brake mechanism that is faulty or the cable is jammed or the cable needs to be adjusted. If there is a problem with brakes it could be caused by air trapped in the brake lines so it will need to be bled or there could be a mechanical fault in the calipers/drums like the piston/s or sliding bolts being jammed and not allowing the fluid pressure to push the brake pads/shoes against the rotors/drums.There may also be a leak in the brake lines or the seals around the pistons, if it there is a leak the fluid will not have enough pressure to push the pistons out which leaves the brakes with a smaller braking force.

 Brake roller tester

 Shock absorber tester

 Inboard drum Park brake

Inboard drum Park brake