Rather than finding out your brakes are worn when you need them most, you can perform regular safety inspections to spot potential problems and keep an eye on normal wear and tear.
Every time you operate your vehicle, you can pay attention to how it behaves when you apply the brakes. If you notice the car pulls to one side or if you hear distinct noises when you brake, you should perform a more thorough inspection. Some cars are designed so the brakes are visible behind the wheel. In other cases, you may need to remove the hubcaps or the entire wheel to get a closer look.
When you examine the brakes, the discs are the first thing to check. They should appear shiny and smooth, but shallow scratches along the surface are normal signs of healthy wear. If you notice deeper grooves, rough patches or uneven surfaces, the discs should be replaced. You should replace both discs if one is excessively worn to ensure uniform driving and braking.
After you inspect the discs, it is time to check the brake pads. They may be located above or next to the discs, and they will overlap the outer edge of the discs. The pads should be at least an eighth of an inch thick, which is roughly the thickness of two pennies stacked together. Any thinner than that, and you should replace the pads immediately.
You should also inspect the brake fluid. Park the car on a flat surface and pop the hood. If you're having trouble locating the brake fluid reservoir, the owner's manual can guide you to it. You will need to remove the cap and visually inspect the fluid. It should be clear in color and above the line indicating more fluid is needed. If the levels are low, add more. Check back in a few days to ensure the levels haven't dropped significantly. If they have, there could be a leak in the tank or in the brake lines. Inspect the rubber hoses for signs of damage such as cracks or rigidity.
Contaminated brake fluid should be changed, and it may be time to replace the liquid anyway. The rule of thumb is to flush the brake fluid and replace it every year or two, but this can vary for different makes and models. Consult your owner's manual to find out the time frame for your particular vehicle.