What are they for?
Simple answer: They stop your car and save your life.
Technical answer: The general misconception is that the brakes squeeze the rotors or the drum and due to friction the car the stops but that’s only a part of the equation. When a car is moving it has some kinetic energy stored in it due to the motion and as soon as we apply the brake this kinetic energy converts into the thermal energy and the car stops in a definite distance. First law of thermodynamics says, “Energy can neither be created nor be destroyed but can be converted from one form to another,” well, in this case it converts into the thermal energy.
Brake Fade and drilled rotors:
Imagine that you are coming down a hill and you are using only your braking system to slow yourself down. After some time your rotors or your drums will start to heat up and every machine component can stand a certain amount of heat and then it fails. After the drums or rotors the brake pads will start to heat up and the resin in the brake pads will start to vaporize, from a very thin layer of gas between the pad and the rotor/drum, and suddenly you will not be able to stop the car by using brakes. This is known as brake fade. We should always use engine braking to reduce the speed of the car when long-term use of braking is required. Even in city driving, brakes should be applied in pulsating manner which gives time to the braking system to shed off some heat.
Engineers found the solution of this problem by introducing cross-drilled rotors or grooved rotors. In case of either new or old vehicles the solution is same. The holes or grooves allow the gas generated due to overheating to escape away from the rotors which gives time to the brake system to cool down while you are still able to use brakes without any decrement in the brake force.
Whether your car is equipped with rotor disks or brake drums, periodic maintenance is the key to a perfectly working system. There are various symptoms which are associated with brakes such as vibration during braking, squeaking sounds, burning smell e.t.c.
At first thoroughly check the disks for wear and tear marks. Very fine lines are normal sign of wear but if there are deep scratches of grooves around the disc then it surely is a matter to be worried about. Scratches can produces whistling sounds and even decrease the braking performance as the surface area in contact of the pad would be less than required. If this is the case then you should either get the brake discs faced or install new ones.
Next, move on the brake pads. Most modern brake pads are designed in a way so that they can produce a whistling sound after certain amount of wear to warn the driver that it’s time to change the pads. You can also judge the pads by peeking through the holes in the rims. If there is 1/8” or less of the pad is remaining, its time get them changed.
Pop the hood and check the level of the brake oil present in the brake oil container it should be at the maximum limit or at least in between the limits. Always use the oil of the same grade that is mentioned in your car’s manual. Check the master cylinder for leakages as it contains very thin rubber washers which often wear out by the effect of heat and continuous pressure in the cylinder.
Wash the tires completely every month to remove the brake dust and dirt and dust build up. Don’t wash the tires very frequently if you live in a dusty area, water will attract more dirt and it will reduce the life of brake discs and pads due to increased friction.