Why are my brakes smoking?

Smoke is the effect of extreme heat, and when it comes to the car, heat arises from friction. This is due to the contact of the pad with the rotor or the pad with the drum. If the driver utilizes the brakes frequently, it will overheat the brake system and create smoke. In addition, the following can also cause brake smoke due to heat generation:

pressing the accelerator and brake pedal at the same time,
harsh braking when driving at high speeds,
repeated braking while driving downhill.

The braking system of a modern car is responsible for safety while driving. Any malfunction of the car brake system parts, the slightest deviation from normal operation, is a sign of the beginning of big problems. If the problem is not immediately eliminated, irreparable damage can happen, up to a threat to passengers' health or even life. But many of us take car brakes for granted, we neglect them while they work.

And once upon a time, the smoke coming from the brakes makes us think, “Why are my brakes smoking?”. Fuming brakes are something that needs immediate attention. And knowing the reasons and precautions will help to avoid this annoying and somewhat serious situation. In this article, we will tell you about the most necessary information that you will need to eliminate smoking of brakes.

Working principle of automotive brake parts

Disc brakes are reliable, efficient, and easy to service. Thanks to this, they are installed on most modern machines. There are front and rear brake discs. The principle of operation is that a caliper acts on the pads, which presses them with its piston. In turn, the pads clamp the disc. The energy of the movement turns into heat, and the car decelerates until it comes to a complete stop (depending on the compression force). This generates a lot of heat, so the pads and discs get warm. In the event of sudden braking, smoke may even emanate.

Parts of car brakes:

brake disk;
pads;
calipers;
cylinder with the piston;
protective cover;
other items.

The brake's material is cast iron. It is inexpensive and has good frictional properties. However, there is also a drawback. From frequent use, the pads become very hot, the top layer melts, followed by warping. And when water gets in, discs heated to several hundred degrees easily crack. The way out of the situation was ventilated brakes and brakes, made of steel alloys.

Basic requirements for disks:

strength;
thermal conductivity;
thermal shock resistance;
low adhesion - the ability to stick;
stability when heated to high temperatures.

With strong heating of the front or rear brakes, the grip in the pad-disc pair disappears, and the first simply slides over the second surface. The braking function is not performed.

But is the heating of the front and rear brakes normal?

During the operation of the car, the braking system works very actively, so the discs get warm. This is normal as kinetic energy is converted to heat.

The normal operating temperature for an urban driving style of a conventional car is at least 200 degrees.
With the more intensive operation, they heat up to a temperature of 400-500 degrees.
Sports cars, operated in a merciless mode, can heat the system red-hot - the temperature of 700 degrees is not the limit.
At Formula 1 competitions, you can see the smoke and sometimes even fire from the braking system of the cars.

Therefore, it can be said that the heating of the parts of car brakes also depends on the driving style. Aggressive behavior on the road, frequent acceleration, and braking heat up the brakes a lot.

The reasons for smoking brakes

The main reason for smoking front brakes is the friction of the elements with the release of heat due to aggressive driving. Please note that overheating is above the normal temperature range.

In addition, the reasons for this phenomenon are:

wear of car brake system parts - discs, pads, calipers;
mechanical damage - it can burst from moisture on the hot metal, be warped;
low-quality elements or the whole unit - this happens when using analogs of original parts and spare parts;
incorrect installation of linings - when doing self-repair, you should be very careful because your safety depends on the operation of the brakes;
brake discs that have long served their service life and continue to operate;
when using rear drum brakes - in this case, the main load falls on the front disc brakes - they heat up more.
replacing the pads is a common cause of overheating. This happens due to incorrect configuration of elements and assemblies that have undergone replacement. As a rule, these are bushings and cylinders.

The main causes of overheating of the rear brakes are similar to those of the front. As a rule, problems arise with calipers and pads, brake cylinders. There may be mechanical failure or deterioration of individual elements. In any case, the brakes are ineffective, and overheating occurs, which can lead to their complete failure.

Another reason for overheating of the rear brake discs is the failure of the front brake group. In this case, the entire load for stopping the car falls on the rear brakes. As a result of the increased load, they overheat.

How to fix the problem of smoking brakes?

It is difficult to eliminate the problem of smoking brake discs on your own, and it is easier to prevent this effect from occurring. However, it is important to identify the problem in a timely manner in order to diagnose and eliminate it. Otherwise, you can get disk deformation, complete system failure, loss of controllability.

Use the following guidelines to prevent the problem of overheating brake discs:

The use of ventilated brakes is recommended - with a void inside and channels for cooling. Braking qualities remain at their best, but the heating during operation is not so high.
Over time, rust forms on the elements of the brake system, the outer walls of the cylinder, which can lead to difficulty in the operation of the mechanism. The result is heating of the discs. Wear on the hub bearing will also cause the brakes to overheat. In this case, the disk will be hotter on one side than on the other. Therefore, it is worth checking this place from time to time and changing this car brake system parts.
A more relaxed driving style should be used to eliminate the problem of overheating caused by aggressive driving. This will positively affect the condition of the vehicle in general and the braking system in particular.

Sometimes there are situations with smoking brakes after replacing worn-out pads with new ones. The situation is unusual - it would seem that a new part should not cause overheating. However, a peculiar smell may appear, which indicates problems and even smoke. To avoid such a situation, you need:

remove the lubricant used for preservation from the new block;
degrease the surface;
clean the hub with a metal brush before installing a new disc - it will be possible to avoid distortions and get rid of debris;
remove the old grease and apply a new, special one - do not use ordinary grease, the brakes can jam at the wrong moment;
we recommend turning the wheel by hand (on a jacked-up machine) - it should rotate freely without stopping after two revolutions.

Overheating can be caused by problems with electronic assistants, in particular, ABS and other systems. Brake fluid can also overheat the brakes. This is due to the loss of its characteristics by the liquid, from which the pistons of the system work ineffectively. Also, after installing new pads, it is recommended to avoid heavy braking for several hundred kilometers. During this period, they "get used" to the surface of the disc.

What happens if you don't fix the problem with smoking brakes?

The main consequences of smoking brakes are the poor performance of car brake system parts. The pad will slide on a hot disc without proper grip, the car will not stop at the right moment, and an accident or other unforeseen situation may occur. After several cycles of acceleration-deceleration, when the brakes are heated to 400-450 degrees, overheating of the discs will lead to boiling of the brake fluid and, as a result, to the system's complete failure.

There are also a few rules to keep in mind to prevent excessive heating of the brake discs:

regularly undergo a technical inspection or preventive check of the main components and mechanisms, including the brake system;
try to avoid aggressive driving with sharp acceleration and braking, especially when the car is already under heavy load;
after replacing the pads, check the presence of brake fluid, the correct installation of parts;
you need to monitor the pads and discs, change them in a timely manner;
use products from trusted dealers like PartSouq that sell genuine car brake system parts;
do not reuse worn out parts;
try not to let water get on the hot metal of the brake system - wash the car immediately after a long drive.

It is not difficult to follow the above rules and recommendations - it is more difficult to replace or repair a failed brake system as a result of disc overheating. Moreover, operating a car with faulty brakes can lead to consequences, up to and including a fatal accident. Watch your car, take care of yourself and your close people.