Brakes – What's Stopping You?

By Karen Johnston January 18, 2017

Quick facts

Your brake system generates up to 1,000 lbs of hydraulic pressure per wheel
Disc brakes are standard on most modern vehicles; drum brakes still common on rear axles
Brake fluid absorbs moisture over time. Contaminated fluid lowers the boiling point and reduces braking force
Catching worn brake pads before metal-to-metal contact saves rotor replacement cost

Did you know that when you step on your brake pedal, you command a stopping force that is 10 times as powerful as the force that sets the car in motion? The brake system of a vehicle can exert as much as 1,000 pounds of hydraulic pressure on each of the four brakes. Yet, we find that many vehicle owners wait for issues with their brakes like squealing and/or grinding noises, or a brake pedal to feel soft before having their brakes checked out. Regular brake inspections are a good way to avoid additional damage that can be caused by driving a vehicle with worn brake parts.

The brake system in your vehicle uses frictional force to slow down and stop the vehicle. On disc brakes the brake caliper is a hydraulic clamp that pinches the brake pads onto the rotor to stop the vehicle. On drum brakes the wheel cylinder is a hydraulic component that forces the brake shoes against the brake drum to slow or stop the vehicle. On both those brake systems you have a master cylinder that converts brake pedal pressure into hydraulic pressure for brake system operation. The other components you have in a standard brake system is the brake hoses and lines that carry the brake fluid from the master cylinder to the calipers and wheel cylinders, and the park brake cable that connects the park brake lever to the brake system in order to keep the vehicle from moving when parked.

Following a regular inspection program for your brakes has a few different benefits. It will allow you to budget for repairs, knowing ahead of time when your brakes will need to be serviced. If you perform repairs before the pads or shoes are metal to metal and completely worn out, it is usually less expensive. Then most importantly, is the safety factor, as your vehicle's brake system would always be in top working order.

The following inspections and maintenance procedures can help prevent potential brake problems:

Checking brake fluid levels at each oil change
Replacing brake fluid according to the manufacturers' recommendations or when it gets discolored, or is contaminated with water absorption
Check brake hoses and lines for rust, punctures or visible leaks
Check brake pad depth on both inner and outer pads
Check caliper operation and wheel cylinders
Check brake shoe depth, and make sure they are free from cracking or fluid contamination

Always be aware of the following warning signs: chirping, grinding or squealing noises, brake lockup, vehicle pulling left or right, reduced braking force, spongy or soft brake pedal feel, brake pedal pulsation and any sign of brake fluid or grease leaking around the wheels. In any of those cases we recommend having it checked out immediately.

Following the inspection procedures can help keep an eye on potential problems and take care of them while they are still small.

Frequently asked questions

Common questions

What is the difference between disc brakes and drum brakes?

Disc brakes use a caliper to clamp pads against a flat rotor. Drum brakes use a wheel cylinder to press curved shoes against the inside of a drum. Disc brakes dissipate heat more effectively and are standard on the front of nearly all modern vehicles; drum brakes still appear on the rear of many trucks and economy cars because they are less expensive to manufacture and work well for the lighter braking loads the rear wheels carry.

How does brake fluid condition affect stopping power?

Brake fluid is hygroscopic, meaning it absorbs moisture from the air over time through the rubber hoses and reservoir. As water content increases, the fluid's boiling point drops. Under hard or repeated braking, overheated fluid can boil inside the caliper, creating a vapor pocket. Vapor compresses where fluid does not, which produces a sudden spongy or faded pedal at exactly the moment you need firm braking. Replacing brake fluid on the manufacturer's schedule or when it appears dark and discolored prevents this.

Can I check my own brake pad thickness?

You can get a rough sense by looking through the wheel spokes at the rotor and caliper. Most pads have a wear indicator tab that produces a chirping sound when the pad reaches the minimum thickness. For an accurate measurement, a technician checks the pad depth with a gauge while the wheel is off. The visual-through-the-wheel check is better than nothing, but it cannot tell you the condition of the inner pad, the rotor surface, the caliper, or the brake hose, all of which affect braking performance.

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All About Automotive — 1850 NW Burnside Rd, Gresham, OR · (503) 465-2926

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