Brake Pedal
Troubleshooting your car'sbrake pedalcan show potential problems in its operating mechanism or in other areas of your brake system. However, correcting brake pedal issues can be relatively easy, depending on the problem and your particular vehicle model. To properly inspect your brake pedal, though, you'll need the repair or service manual for your particular car make and model. If you don't have this manual on hand, you might be able to consult a copy in the reference section of your local public library. The next steps apply to vehicles with power brakes.Checking your brake pedal reserve distanceWhen completely depress, your brake pedal-depending on your particular vehicle make and model-should have an specific distance between its stepping board and the car's floor. To check brake pedalreserve distance, apply the Parking brakes, block all four wheels using wooden blocks or something similar, and shift your transmission to Neutral (manual) or Park (automatic). Start the engine and let it idle.Now, ask an assistant to fully depress and hold the brake pedal down. Using a metal ruler, measure the distance between the brake pedal and the floor, and compare your measurement to manufacturer specifications. An average brake pedal reserve distance is about one inch (25mm). If your pedal reserve distance is out of specification, check the push rod adjustment, the brake lines for air or, if your rear wheels come with drum brakes, the adjusting mechanism in the rear brake assembly.If you recently removed or replaced the brake master cylinder or brake booster, the push rod might be in need of adjustment. The push rod connects the master cylinder to the brake pedal. Consult your repair manual, if necessary. If your brake fluid level is very low, it is possible that air has entered the system. In this case, you'll need to bring the fluid to the correct level and bleed the brake system as well. Also, problems in the automatic adjusting mechanism in one of the drum brake assemblies may be causing problems to your pedal reserve distance. Inspect the mechanism, if necessary.Brake pedal heightBrake pedal heightrefers to the distance between the brake pedal-at its resting position-and the floor. Measure the height distance using a metal ruler and compare to the specifications listed in your service manual. If necessary, check for worn out bushings, the pedal's return spring or a master cylinder push rod in need of adjustment in the brake pedal mechanism.Brake pedal free playIf you are like most drivers, chances are you haven't noticed the small amount offree playon your brake pedal. If you depress your brake pedal lightly with your foot, you'll notice that the pedal travels a short distance before you actually begin to engage the brakes. All vehicles need this small amount of pedal free play to keep the brakes from dragging after releasing the pedal.To measure pedal free play, make sure the wheels on your vehicle are blocked, your transmission is in Neutral (manual) or Park (automatic), and your Parking brakes are engaged. Start the engine and let it idle. Using a metal ruler, measure the distance between your brake pedal and the floor. Now, slowly depress the brake pedal with one hand and stop as soon as you feel you are about to engage the brakes. Hold the brake pedal in this position and measure the distance between the brake pedal and the floor once more using your free hand. Then, release the pedal and turn off the engine.Subtract the second measurement from the first measurement. This is your actual brake pedal free play. Compare your pedal's free play distance to the one listed in your service manual. Incorrect free play may be caused by a unadjusted master cylinder push rod, worn out brake pedal bushing or return spring.Whether or not you are experiencing problems with your brake pedal, it is a good idea to inspect it from time to time as part of your vehicle maintenance tasks. It'll help you to become familiar with your brake system, its operation and to spot potential problems. If you need to make adjustments to your brake pedal, follow the specifications listed in your vehicle service manual.
