All the safety systems that our car incorporates are important, but if there is one that is really decisive to avoid the accident and especially when this is imminent, it is the brake system. The brakes are the main safety system of any vehicle and also the oldest, as you would expect.
Avoiding a collision with another vehicle, not running over a pedestrian or not going off the road will depend to a great extent on being able to stop in time safely. The skill of the driver at this time is essential, but if not accompanied by optimal functioning of the braking system, the maneuver can end in failure and also in a possible misfortune.
A basic knowledge of the operation of this system will help us to interpret possible signs of failure and also make us aware of the importance of maintenance. Despite the fact that 97% of drivers think that the brakes are the most important safety system of their car, only 13.5% of Spanish drivers would know how to detect if their brake system has any problem according to a study by Roadhouse.
Basic operation of the brakes
Mechanical, hydraulic and electronic systems make up the operation of the brakes. The driver activates the system through a pedal, this force is amplified by a servo brake that acts on a pressure pump. The brake pads or brake shoes in the case of drum brakes are activated by a system of pipes and hydraulic cylinders.
The brake pads or shoes stop the rotors by friction. The rotors can be in the form of discs or drums, which rotate in solidarity with the wheel, causing it to stop. The configuration is very different in case of being a disc or a drum. Disc brakes have, as their name indicates, a disc-shaped rotor that is pressed by a caliper that has the pads incorporated. The drums, meanwhile, are something like a hollow wheel inside which are hidden the shoes, which are the pads of the disc brakes, but instead of pressing on the outside, make the friction on the inside walls of the hollow wheel. This type of brakes can suffer greater problems of overheating and loss of braking power and therefore have been stopped. Currently they are used in very small or low cost cars, but only in the rear wheels.
Helped by electronic systems such as ABS that prevents the wheels from locking, it optimizes the effectiveness of braking and allows control of the vehicle by the driver in case of emergency braking.
The development of driver aids and assistance in this system has evolved greatly in recent years. Toyota incorporates the Toyota Safety Sense, which among other systems has a Pre-Collision Safety System, which if it detects the possibility of a collision, in addition to alerting the driver, it activates the brake assist. If the driver does not brake in time, the brakes are automatically activated to avoid or mitigate the collision.
Habit makes us overlook things
Once we have a basic idea of how the brakes work, we move on to the possible signals that the system sends us when they are in poor condition. It is important to know the car and how its brakes work, because every vehicle is a world and everything may go perfectly and it may not seem so to us.
Many defects of this system or even possible serious failures are overlooked by many drivers because they are gradually adapting to abnormal operation.
MANY DRIVERS DO NOT NOTICE THE WEAR AND TEAR AS THEY GET USED TO THE FEEL OF THE PEDAL
One of the first sensations we have when using another car is the change in the feel of the pedals. The hardness of the clutch or brake pedals is usually different from what we are used to in our car and we may even notice that the braking is more or less effective than usual.
Due to wear, the brakes are gradually losing effectiveness and the driver is adapting to these changes. Over time the braking distance increases, the pedal becomes spongy, and until someone else does not drive our car and tells us: but what a bad brake your car, we do not realize that we have to take it to the workshop to check the brakes.
We can be guided by some reactions or feelings
The brakes are of vital importance, as has already been mentioned, although it is also worth remembering. They are absolutely essential and a system in poor condition is very likely to cause an accident. It may not be now, nor later, but it will happen. Therefore, we are going to list some symptoms that must be taken into account.
- Spongy brake pedal
Although, as we said at the beginning, the driver gets used to the touch of the pedal, there comes a time when it becomes excessively spongy. The cause can be found in a very deteriorated brake fluid, leaks in the brake circuit, the air in the same circuit, or a defect in the brake pump or cylinders.
Brake fluid is essential to the operation of the system because it transmits pressure. This fluid is not compressed, but it is hygroscopic, i.e. it absorbs moisture. Vapor bubbles if compressed, which makes the mattress within the circuit and produces that feeling in the pedal.
Manufacturers recommend replacing this liquid every 2 or 4 years, something that is unknown by many drivers and ignored by others, since this feeling of insecurity is not perceived as it is with other elements.
- Noise and Vibrations
Vibrations can be due to different reasons: abnormal wear of tires, wheel bearings, steering alignment; but when they are due to the brake system, they can be due to a deformation of the brake discs or to pads with irregular wear.
Brake disc wear, like that of other elements, depends very much on each driver’s driving style and the maintenance given to the vehicle. For example, failure to change a badly worn pad in time and continuing to drive with it can cause abnormal wear on the brake disc and lead to worse damage.
On the other hand, pad wear has a ‘tell-tale’; nowadays most vehicles have a tell-tale on the dashboard, otherwise a metallic noise will give away the bad condition of the pads. When this noise appears it may be due to wear or excessive crystallization due to overheating of the surfaces. In both cases it is necessary to replace the pads.
- Longer braking distance
The need for more and more space to stop may be due to other factors such as the road surface, load, suspension, or tires in poor condition. But if we stick to the brake system, this increase in stopping distance is due to the wear and tear of the elements that make up the system.
For effective braking, a number of circumstances must exist. Firstly, that the transmission of force is ideal for which both the operation of the brake servo and the state of the brake fluid play a key role, and secondly that the effectiveness of the set pad-disc, shoe and drum is optimal.
In the latter case, when there is wear on these parts, there is a significant loss of efficiency, which will result in an increase in distance. In addition to an increase in braking distance, we may encounter unexpected skidding.
As always, the periodic maintenance of these systems and the replacement of the deteriorated parts in time can prevent us from incurring greater costs in the future or, more importantly, from having an accident.
- The brake pedal is very hard
Stop a car of a tonne approximately, moving at a speed of 100 km / h with the only force of our foot is something really complicated, only within reach of Pedro Flintstone with his “trunk” and therefore, cars, in their evolution, have incorporated a servo system (before there was no servo and was the force of who was driving, which stopped the car).
THE BRAKE SERVO AMPLIFIES THE FORCE EXERTED BY THE DRIVER ON THE PEDAL
What a brake servo does is multiply the force we make on the pedal, sending more pressure to the circuit and therefore to the brake system, which does its job more effectively. If you want to check its operation try to operate the brake when the car is off, you will see that the first time will respond, but the next time the car will not stop no matter how hard you press the pedal.
A failure in the brake servo will result in a hardening of the pedal, if you notice this symptom take the car to the workshop as soon as possible for a professional to check this system. However, there are vehicles whose pedal feel is hard, without this meaning a problem in the brake servo. They are usually sports and high performance models, although it can also occur in any other car.
Brake system maintenance
Proper maintenance and control will help prolong the life of the elements and make them work at their best, but the way you drive also helps, and a lot.
GOOD MAINTENANCE CAN PREVENT SERIOUS BREAKDOWNS THAT ARE MUCH MORE COSTLY
A progressive driving, anticipating situations helps not to abuse the brakes. If we approach a traffic light there is no point in stepping on the gas to hit the brakes at the last minute. Besides being unsafe, it causes greater wear on tires and brakes. By the way, we also use up more fuel.
It is important to avoid long braking on long descents and mountain passes, this produces an overheating of the system, which can lead to the dreaded “fading” that is, heat exhaustion of the brakes. Long braking is done to achieve a smoother and more controlled ride, but with slight pressure on the brake pedal.
Images | Toyota Global Newsroom
Hi, I’m Liam. I’m the initiator and writer of this blog. Cars were and will be my first love, and my favorite hobby, that’s why I decided to start this blog and write about my discoveries and techniques to improve my cars or repair them.