Vehicles use their engines as a means of converting energy into work that is its movement.
By this, I mean whenever a vehicle moves or conveys any kind of heavy loads, it is doing so because of the power outputted by the engine in the vehicle. It is taught in physics that whenever an object, such as a vehicle, moves, it possesses kinetic energy, the energy of movement. To stop the vehicle from moving, this energy must be given up or changed.
For example, if a vehicle is moving and then crashes into a solid object, it will be forced to stop rapidly. This is a clear indication that it has used up all its kinetic energy in stopping, although by crashing into the object it has also damaged itself. The function of the braking system is to bring a moving vehicle safely to rest. It does this by using friction to stop the wheels from revolving.
This is achieved by the use of brake pads or shoes which are made of special material that exhibits maximum friction. These are deployed to act against the wheel disc, or wheel drum at the rear, and the kinetic energy is converted into heat which is then expressed by the air as it flows past the brakes. Friction is the resistance to movement of one object sliding over the other.
This is easily demonstrated by sliding one hand across the other whereby the harder you press them together, the more energy you will find you are using, which results into greater friction and higher temperatures. Vehicles have become progressively faster and, as a result, more heat is normally generated by the brakes when bringing the vehicles to rest.
Vehicle brakes are supposed to function silently, but severally, one will hear a sharp squeaking sound emitted from a moving vehicle every time the driver actuates the brakes. What could be the cause of this? These are some of the reasons brakes squeak:
– Bad brake material. There are brakes that are made of unsuitable material that is so hard that it sometimes creates fire instead of just harmless friction when the vehicle tries to brake. This will emit some noise, but also sometimes fail the vehicle to brake effectively. These materials are usually composed of some metals and other hard materials that do not brake so easily. The fire created during braking sometimes damages the disc or drum whenever the brakes rub against them.
– When the disc or drum surfaces are not properly aligned. New brake padsshoes will have difficulty as their friction materials try to align with the disc or the drum, and as this continues the outcome will be the noise.
– Rust and dirt on the surface of the disc on installing new brakes would also lead to the generation of noise as one tries to brake, most especially if the vehicle has been parked for some time. But with time, this goes away if the material used is a good one.
Finally, always ensure that you use genuine brakes for the effective braking of the vehicle. Also ensure you change the brakes on time to avoid further future costs.
Robert Kato is a mechanic who can be reached on:
Source : The Observer