To keep a car in good condition, it is necessary to do routine maintenance on it, and one component of this maintenance is replacing the brakes on occasion. If you have just installed brand-new brakes, you could have picked up on an unpleasant odour and even caught a whiff of smoke.
Do new brakes smell and smoke? It is not unusual for freshly installed brakes to emit pungent odour and light smoke. The odour and smoke are so typical that the phenomenon that causes them has a name: polymerization. Your brand-new brakes need to be broken in, which is essentially the same thing as a curing procedure. The gases produced during the curing process are responsible for the smoke and the scent.
New brake pads go through a “break-in” or “bedding-in” process after being placed. The resins and adhesives in the pads will cure during this time, and the pads will start to take on the shape of the rotors.
The brakes may generate some smoke and a little odour due to this operation. The smoke may be seen coming from the wheels, and the scent is often described as having a burning or chemical stench. It’s vital to understand that not all new brakes will produce an audible noise or smoke since this depends on the kind of brake pads used and the driving environment. For instance, hard braking or driving in stop-and-go traffic may increase heat and friction, making brake smoke and odours more obvious.
Additionally, it’s critical to differentiate between typical brake smoke and odours and those that point to brake-related issues. A braking problem, such as a jammed calliper, a cracked rotor, or faulty brake pad installation, may be indicated by excessive smoke or a burning smell that lasts beyond the break-in period. In these scenarios, it’s crucial to have the brakes checked by a qualified technician to guarantee the car will operate safely and reliably. In conclusion, it is typical for new brakes to produce some smoke and a minor odour when breaking in. This may continue for up to 300–400 miles of driving and is brought on by the resins and adhesives in the brake pads hardening. However, if there is a lot of smoke or a burning odour, the brakes may need to be checked by a qualified technician.
Now that you know it is not very urgent if your new brakes emit any odour or smoke, we can examine the origins of these phenomena in further detail.
After Changing the Brakes, is it Normal to Smell Like Something Is Burning?
If you have just replaced your brakes and noticed a burning odour, you could be concerned if you are unaware that this is a natural and expected part of breaking in new brakes. When you apply the brakes, whether you do it yourself or have a professional do it, you may smell something burning and/or see some smoke. The process in question is known as polymerization, as was just described.
What is Polymerization?
The polymerisation process is complex, yet its meaning may be summed up in a few simple words. The first few times you apply pressure to the brake pedal will kick off a process known as “curing.” This occurs when the brake pads rub against the rotors as they rotate. This results in friction, producing a great deal of heat. The curing process begins once the brake pads make contact with the rotors.
The curing process results in the formation of gases, which provide the odour and smoke you are most likely seeing via your rearview mirror. You may be perplexed why the producers do not merely cure the brakes before installing them to eliminate the odour and smoke.
Some technicians will begin the curing process before the brake pads are made available for purchase. In these circumstances, the brake pads are “burnt in” by the manufacturer.
To create a layer of friction on the first one to two millimetres of the brake, the brake pads are subjected to intense heat and pressure for a short time. If the manufacturer does this, you will have to break in your new pads for a shorter time.
Not all manufacturers cure the brakes first because it is optimal for the brake pads to be broken in by the rotors on the vehicle they are meant for. The following are the results you will get by doing this:
- Improves pedal feel
- Reduces the scream of brakes
- Reduces brake dust
- Protects and extends the life of your rotors and pads.
All of this ageing is achieved by a process called bedding in, also known as burnishing, which is done to your brakes. This essentially refers to applying more pressure on the brake pedal. Let us study the stages that comprise this process.
Bedding-in Brakes
As was discussed, several manufacturers cure the brake pads before installing them in the vehicle. In these circumstances, there is no need to bed the animal in. However, in most instances, you will be required to bend or break in your brakes.
The following are some advantages of using bedding during breaks:
- Removes the substance that causes friction in the brakes
- Maintains a consistent thickness of the material transferred from the brake pad to the rotor (transfer layer)
- Smoothes the surface of the rotor
There are a variety of brake pads available, and the majority call for a bedding-in procedure exclusive to the manufacturer. This information is always included in the documents that the manufacturer provides.
It is of the utmost importance to adhere to the instructions with as much precision as possible since doing so guarantees an even transfer layer. If the layer is not even, you can have the following issues:
- Vibrating brake pedal or steering wheel
- Compromised brake performance
- Discomfort while driving
How to Bed In Brakes: A Step-by-Step Guide
The process of “bedding in” your brakes demands that you accelerate quickly and then decelerate several times rapidly. It is recommended that you do this first thing in the morning in an area with little traffic to follow the procedures exactly as they are written. Be sure to follow the guidelines provided by the manufacturer, but in the meanwhile, here is an example of what the bedding-in process may look like:
- First, reach a speed of sixty miles per hour (MPH), then use the brakes many times. This gets your brakes up to the temperature at which they usually operate and prepares the pads and rotors for the considerable heat you will create in the following actions.
- Put severe pressure on the brake pedal to increase your speed to 60 to 10 miles per hour. Remember that you are not coming to a complete stop; nonetheless, you need to push the brakes pretty firmly, but not so much as to activate the anti-lock braking system (ABS) or the wheels lock mechanism.
- When you reach 10 miles per hour, increase your speed to 60 miles per hour, then use the brakes to slow down to 10 miles per hour.
- Continue this cycle eight to ten times without ever reaching a complete halt. Coming to a full stop may cause excessive brake pad material to be left on the rotors, which will reduce the effectiveness of your brakes.
- After completing your last cycle, you should accelerate and drive about for a while, applying as little pressure as possible to your brakes so they can cool off.
If you have done an excellent job of bedding in your brakes, the rotor of your vehicle should have a thin layer of a light grey coating and a slight tinge of blue. The braking material was placed onto the rotor, which is what the film is. The rotor has achieved the proper temperature to begin its break-in process, which is indicated by the blue tint.
You may need to go through a second bed-in cycle after installing new brake pads but keeping your old rotors on the vehicle. Before beginning the second cycle, giving the brakes some time to cool down is essential.
Other Reasons for Smoke and Odor With New Brakes
A few more factors might contribute to the odour or smoke coming from your brand-new brakes. The following are some other options to consider:
- The rust-preventative coating was applied to the new rotors.
- Stuck calliper
- Putting the pedal to the metal
Let us examine each of these potential problems one at a time to see which is most likely to be the source of the smoke and odour.
Rust inhibitors have been applied to the new rotor
If you have just fitted new brake pads and rotors, this may cause the issue. Rotors often come coated with a rust inhibitor when they are manufactured. The rust inhibitor will be gone after the first few times you apply the brakes since it will burn off. This may result in smoke, which may also produce a scent.
To prevent this problem as painlessly as possible, remove the coating from your new rotors before installing them by thoroughly washing them with dish soap and water. There is also the option of using brake cleaner to remove the coating.
Stuck Caliper
The smoke coming from your brakes may be due to a calliper that has become trapped. This problem often arises only with older brakes, but it is essential to check for it on the off chance that it might be the root cause.
Please permit me to begin by describing the function of a calliper. Assuming that your vehicle utilises disc brakes, the rotors are fastened to your car’s wheels. The calliper applies pressure to the rotor, which results in friction and decreases the wheel’s rotational speed.
The sticking of a calliper may be caused by rust or dirt. Your brake pad may smoke if it overheats substantially due to a jammed calliper, which will cause the place to overheat.
In addition to the presence of smoke, a solid indication that you have a jammed calliper is when you notice that one side of your brakes has much more wear than the other. You can also remove the wheel and have someone else apply the brake while you keep an eye on the brake pad. If the spot does not return to where it was when the rotor was removed, the calliper is probably stuck.
Riding the Brakes
Using your brakes may cause a burned smell to come from the vehicle, regardless of how old or fresh the brakes are. You could have been driving down a particularly steep slope when you decided to keep your foot on the brake for most of the trip. Because of the increased friction that will result from this process, a smoky odour will be produced.
If this occurs, you will want to cool down your brakes as soon as possible since you risk causing damage to them if you allow them to continue heating up in the exact location on the rotor.
To bring your brakes back to operating temperature, you should attempt to drive or coast for at least five minutes without using the brakes. If there is traffic in the area, this will not always be doable, so you will have to do the best you can. Your vehicle’s braking system is, without a doubt, one of its most critical components. You want to be with them; therefore, if none of those above alternatives seems to be the reason for the smell and smoke coming from your new brakes, you should have them inspected as soon as possible. Spending a small amount of money to go along the road safely is unquestionably the superior option.
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