If you find it difficult to wake up in the morning, nothing is a more effective wake-up call than a spongy brake pedal. If you're on your way to work and suddenly find that you have a lot less efficiency in the system when you're trying to bring the vehicle to a halt, it's time to wake up — quite literally. Usually, this shows that you have air within the system, and you'll need to rectify this fairly quickly. What should you be doing next?
How to Proceed
It's not unusual for air to get into your car's brakes, and when it happens, you simply need to "bleed" it out. The manufacturers have built tools into the system to allow this to be done when necessary.
Begin by jacking the car up and putting axle stands at the four corners. This will allow you to safely remove all of the wheels. Then, go to the front driver's side and look behind the brake disc. You will see a large bleed screw attached to the metal caliper, which you should turn very slightly using a spanner of the correct size. Be careful not to damage the screw, and just turn it a little.
Next, open the bonnet and have a look at the fluid within the brake master cylinder. If it's not up to the indicated line, add some, and then leave the top off the cylinder.
Attach some clear plastic tubing to the end of the bleed screw that you just loosened and put the other end into an empty container. Elevate this container so that it is above the screw, and then get a friend to sit in the car to pump the brake pedal. As your friend does this, the excess air will escape through the bleed screw and into the container, together with some brake fluid. After pumping the pedal a few times, ask your friend to maintain pressure while you tighten the bleed screw back to its original position.
Rinse and Repeat
You now have to repeat this exact process on each of the other wheels, but before you do this, please ensure that there is enough fluid within the reservoir before you continue. You will always know when the air has been eliminated from that part of the system because there will be no more bubbles in the evacuated solution.
Your Final Steps
Once complete, remember to put the cap back onto the master cylinder, reattach all the wheels and lower the car. However, this is not the complete story, as you will need to take the vehicle in to your mechanic for a complete check, just in case there are any contributory issues.