What causes brakes to squeal?

There are many reasons why a person can experience brake noise.  Sometimes brake squeal can be an indicator that there is a problem.  Maintenance is required if you experience brake squeal for any of the following reasons:

• Lack of friction material (brakes need to be replaced)
• Loose fitting brake pad in the caliper
• Loose fitting or missing brake hardware (i.e. shims, anti-rattle clips)
• Loose  caliper hardware
• Debris caught between the rotor and the protective shield.
• Heat cracked or worn rotors
• Uneven finish on resurfaced rotors

Sometimes a user may experience brake noise when no maintenance is required.  Brake squeal is typically caused by vibration between the brake pads, rotors, and brake calipers. Some brands of semi-metallic brakes are more likely to experience brake squeal due to the metallic ingredients in the brake pads.  

My brakes have started to squeak when I apply the brakes, could there be a problem?

Yes and No. Some brake noise is normal and unavoidable. Demanding driving conditions, traffic congestion, severe braking, dusty or sandy conditions, abusive braking, even humidity can cause unwanted brake noise. These conditions promote "glazing" or "crystallization" which is a hardening of the brake pad/shoe surface or the entire brake pad. The lesser "surface hardening" can usually be sanded off with common sandpaper, the worse condition "entire pad crystallization" would require pad replacement to eliminate the noise. However, the cause of the hardening, if not corrected would simply re-crystallize the pads, simple Pad replacement would not be a good brake repair. Have your car check by a Certified Safety Expert to confirm the need for repair; the high demand brake use problem can easily cause more damage than just to the brake pads. Brake noise can also occur if the brake system has a "weak link". The brake system is only as good as its' weakest component. A faulty part can cause a chain reaction of failures to other components that could cause problems ranging from more than normal occasional noise to total brake failure. Have your brake system completely checked and serviced by a quality conscience brake system specialist.

Sometimes my brakes make a grinding or groaning noise that only happens at very low speed stops. Are my brakes going bad? 

Only a complete brake system inspection by a competent brake specialist can give you the truth, however the particular noise you are describing is generally considered normal, particularly on vehicles with semi-metallic pads or most front wheel drive cars. The noise is simply a vibration that can be more felt than heard coming from the front disc pads because on slower stops you don't have the brakes applied fully which allows them to vibrate against the rotor surface. Usually no service is required as the noise is unavoidable, however if the noise is constant and occurs at almost every stop, the brake system should get immediate service.

Why does my brake pedal pulsate while applying the brakes?

A: Under heavy braking, you might feel the ABS (Antilock Braking System) working. If you are getting a pulsation under normal braking,  the brake rotor may be warped.This warpage is generally caused from heat. A qualified technician can use a tool called a dial indicator to identify if a brake rotor is warped.

Do brake rotors need to be replaced when replacing the brake pads?

A: Not always. Brake rotors can usually be refinished using a brake lathe. This refinishing process is sometimes called turning the rotors. The technician will measure the thickness of the rotor using a micrometer and determine if the rotor can be refinished. Auto manufacturers list the minimum allowable rotor thickness for each vehicle model. If the rotors are excessively warped or worn to the extent that they cannot be turned, then they must be replaced.

Recently I have noticed that my car has become increasingly harder to stop and the brake pedal seems to travel down a lot farther than it used to. What could be wrong?

The problem could range from a simple adjustment or air in the system. Early warning symptom of total failure. Having a professional perform the necessary bleed, adjust and inspection to determine exactly the nature of the problem would be advised. Because of anti-lock brakes and the ever increasingly complex braking systems it is a good idea to not risk damage to extremely expensive components. But to allow a certified technician to perform the task.

After recently having my brakes repaired, the service adviser informed me that I need to set my parking brake every time I park my car. He said it assisted in keeping the rear brakes adjusting, is this true and how?

Your service adviser is absolutely correct and better educated than most. Most modern cars and light trucks use what is called a single or non-servo rear brake. These brake designs have the self adjuster connected to the parking brake assemblies and do require park brake usage to ensure rear brake adjustment. This not only ensures proper rear brake operation but also helps keep the brake pedal high and the brakes functioning better, keeping excess load from prematurely wearing the front brakes. The days of having to sharply apply the brakes while moving in reverse are almost gone; some vehicles still require this, so check with your brake system specialist to find out what kind you have.

While changing my oil, I checked my brake fluid and it was a little low so I added some and noticed that the new fluid looked very clear compared to the old fluid. Is the fluid going bad or is it normal?

Both. Brake fluid is the most overlooked component in the braking system of vehicles and it is one of the most important components in that system. Brake fluid is formulated to tolerate moisture absorption, control rubber expansion and corrosion, and acts as a lubricant. It also must not boil or freeze in brake systems over a wide range of operating temperatures. The level is checked occasionally, but very seldom is brake fluid completely replaced unless the vehicle's braking system undergoes a major overhaul. Most technicians know that brake fluid deteriorates with age due to moisture and contamination. DOT 3 and DOT 4 brake fluid are polyglycol based. This glycol ether blend of fluids is "hygroscopic" which means it attracts and absorbs moisture. This process takes place every time you take the cap off the container or check the fluid in the master cylinder reservoir. Moisture is even absorbed through microscopic pores in rubber seals and hoses in the brake system. Also keep in mind when you use your brakes, heat is generated at the friction contact points. As your vehicle sits, your brakes cool down. Therefore, over a period of time the heating and cooling action of your brake system will condense moisture in the closed hydraulics system. DOT 3 and DOT 4 brake fluid will absorb that water and keep it from effecting hydraulic components and helps prevent or at least slow down the corrosive effect. Even though brake fluid absorbs moisture, it cannot continue to absorb it indefinitely, which is why it is recommended that you flush the system and refill with fresh brake fluid every 24-30 months.Or check your owner's manual for the manufacturers recommendation.