Why Should You Worry About Dirty Wheels?
If your car's wheels have been looking a little dirtier than usual lately, your first thought probably isn't that you have a brake problem. Although it may not seem like it, dirty wheels can be a canary in the coal mine for issues with your braking system. Paying attention to this seemingly unrelated symptom can help you to discover severe problems before they put you in danger.
Understanding Brake Dust
When you hit the brake pedal, your car's brake pads use friction to bring the vehicle to a smooth, controlled stop. In doing so, they produce two byproducts: heat and dust. Since your brake pads are sacrificial wear components, some amount of friction material burns off with each brake application. Over time, this produces dust that you may notice accumulating on your wheels.
The amount of dust produced by your brakes can vary significantly based on their age and type. Metallic pads tend to create significant amounts of dust, while ceramic pads often generate less. Your driving habits and the level of wear on your pads can also influence how much dust you see on your wheels from day-to-day.
Knowing When to Worry
Brake dust is a normal part of your vehicle's operation, so its presence isn't usually a concern. If you notice an even amount accumulating on all of your wheels, then it's likely that you don't have a problem. You should be more concerned, however, if one wheel consistently produces more dust than any others. More dust at the front or rear of the car may also indicate a problem.
If you do notice that one wheel seems consistently dirtier than the others, you can also check for excessive heat. When your pads drag against the rotors for longer than usual, they produce extra heat along with excess dust. Do not touch your wheels as they may be very hot, but instead feel for warmth radiating away from the affected wheel after a drive.
Discovering the Underlying Cause
When one wheel produces excess dust, it usually means that your brake pads are not correctly retracting from the rotor. This "dragging" effect may be the result of a sticking caliper piston or even a problem with your hydraulic brake lines. Depending on the severity of the issue, you might experience your car pulling to one side during braking or light acceleration.
While dirty wheels may not immediately come to mind as a symptom of bad brakes, excessive brake dust is sometimes a cause for concern. If you notice that one of your wheels is always unusually dirty, it's time to have a professional, like Greg's Garage, evaluate your braking system.