Brakes are one of the most important parts of your car. Other breakdowns might be a pain, but if your brakes fail, it could be a disaster. It’s possible to avoid accidents like this if you keep an eye on your brakes.
Fortunately, most people already have the tools they need to check their brakes: their eyes, hands, and feet. Before you use any fancy tools, check the brake fluid level in the reservoir; look at the condition of your brake pads; look for bubbles in the hydraulic line; check for leaks, wear, and rust; and make sure the brake indicator light is on.
Your feet and sense of touch can tell you about a lot of things based on how the pedal and brakes work, like if the master cylinder or vacuum booster is worn out. Brakes that aren’t working properly could mean that you need to bleed your brakes. A soft pedal could mean that you need to do this. If you want to bleed your brakes and check your brake-proportioning valve, we’ll tell you what tools you’ll need below.
As a start, though, let’s look at how to check the brake fluid in your car. Remember that unless the brake fluid has rust or looks muddy brown, you can’t tell when it needs to be changed by looking at it. Instead, use one of these:
- Optical refractometer: Measures how light bends through a fluid sample to figure out how much moisture there is and how quickly it will boil.
- Chemical test-strips: Change color to show copper buildup, which means that the fluid’s anticorrosion additives are almost out.
- Electronic testers: You can figure out how much boiling point brake fluid has, either by measuring how much it conducts or, better, by boiling a sample of it.
Gauges are very important for checking the hydraulic and pressure conditions of your braking system. To find out if a proportioning valve isn’t working right, put a hydraulic gauge on both sides of it. You can check engine vacuum, which is used by the power brake booster, by connecting a vacuum gauge to a supply hose that comes from the intake manifold.
For the brakes, you’ll need a micrometer or vernier calipers to measure the thickness of the brake pads and the thickness of the rotors. You’ll also need to measure the rotor runout (wiggle), flatness, and parallelism of the rotors.
You’ll need a computerized scan tool or diagnostics tool and the right shop manual to figure out what’s wrong with electrical mechanisms or switches, like parts of the Antilock Braking System (ABS).
As soon as this has come to a slow, smooth stop, it’s time. Take care of your brakes, and they’ll take care of you.