How brakes work, and the warning signs it may be time for new ones

Your vehicle’s brakes use friction to reduce speed, and because they do, brake pads and rotors wear out and need to be replaced periodically. The tricky part is knowing when it’s time for a brake job. That’s where a periodic, visual inspection by a m
by Rich Ellis

Brakes 101

How brakes work

Vehicle brakes operate by a hydraulic system. Pressing the brake pedal forces brake fluid to move throughout the system. On vehicles with four-wheel disc brakes – which most are today – the brake fluid compression initiates a process resulting in brake pads squeezing the brake rotors – large metal discs at each wheel – generating friction and slowing the vehicle. The friction required to stop a 4,000-pound vehicle, however, is considerable, and each time the brakes are used more friction material wears off the brake pad surface until it reaches a point where the pads need to be replaced.

How long should brakes last?

Generally, brake pads can last anywhere from 25,000 to 65,000 miles. It’s a wide range because several variables affect pad wear and lifespan.  

 1.     Driving style and environment. Driving in hilly or mountainous regions, or in stop-and-go traffic will increase brake pad wear, as compared to driving mainly highway miles over flat terrain. Similarly, towing a trailer or frequently hauling heavy loads also increases pad wear, as do hard, fast stops. 

2.     Brake pad material. The type of pad recommended and how hard or soft the friction material is can affect lifespan and differ depending on vehicle manufacturer specifications, type of driving, and stopping power required. The most common brake pad wear material includes ceramic, semi-metallic, or organic – featuring glass, rubber, or Kevlar for the wear material.

Warning signs that it could be time for new brakes

Fortunately, many brake pads are designed to give drivers advance warning that it’s time for new brakes, with some of those signs including:

1.     The brake wear indicator dash light illuminates (if equipped)

2.     A squealing or grinding noise from one or more wheels when using brakes

3.     Brake pedal feels soft or squishy or goes very far down to the floor

4.     It seems to take longer to stop

5.     Vehicle pulls to one side when braking

6.     A noticeable vibration when braking

If your vehicle exhibits any of these warning signs, or it’s been approximately 25,000 to 60,000 miles since the brakes were replaced, ask your mechanic if it could be time for new brakes.

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