Excessive vibration going downhill is often caused by warped brake rotors due to excessive heat. To avoid this, using lower gears in an automatic transmission while travelling downhill is recommended.

As an example, if you are driving down Old Belair Road or Shepherds Hill Road and you notice you are feeling a vibration through the whole car and especially through your steering wheel when you get to the bottom of the hill, it’s most likely because your brake rotors are warped.

This is caused by excessive heat in your brakes, which can easily be avoided by using your gears in your automatic transmission while you’re travelling downhill.

You need to gear down the transmission while going down the hill to keep you within the speed limit without using your brakes.

It very much depends on the style of automatic transmission on whether you would have to go down two or three gears. You’ll find that you will save on brakes due to excessive wear and your brake shudder will not return.

Just think of it like you’re driving a manual gearbox, you don’t go down the hill in fifth gear. When driving a manual car you use the correct gear to hold the car up so it does not go over the speed limit.

Similarly in an automatic car, if you shift into one of the numbered gears (from D to 3 for example), it will hold the gear and the cars engine will rev higher, slowing the car down as you descend the hill, saving your car from overheating brakes.

The disc (left) - dark colour and lines indicate overheated brake disc. Brake backing plate (right) - this should be dead straight.

As a side note, at Blackwood Dyno Tune & Service our Safe-T-Stop Brake test machine which checks braking force pressures on each corner of the vehicles wheels, has now been upgraded to the same specifications as the SA Government inspection station at Regency Park.

As you can see, we are very serious about brake safety at Blackwood Dyno Tune & Service.