You are slowing down to stop at a traffic light and find that the brakes are soft and the pedal is depressed. This may be a sign that air has entered the brake hoses. Bleeding the brakes is a two-person job and requires a coordinated effort. The result will be a harder pedal and a more responsive brake system. Here's how to do it.
Steps
Part 1 of 3: Preparation
Step 1. Make sure you need to bleed the brake hoses
The brake pedal moving down often indicates that the hoses need to be bled. However, it is important to confirm that the pedal down problem is not caused by anything else.
- Try a simple test as soon as you are stopped at a traffic light. Keep steady pressure on the brake pedal. If it goes down completely then you will need to have the car's brake system checked by a specialized mechanic to confirm that the problem is not caused by anything else. If the pedal remains at the same height then you may just have to remove the air that has entered the brake hydraulic system.
- The lowering of the brake pedal can be caused by other things that can be dangerous. For example, there may be a hydraulic problem such as a faulty master cylinder, a leaking rear wheel cylinder, a caliper or ABS problem. This is why it is important to rule out these possibilities by having the machine inspected by a professional before proceeding.
Step 2. Place the machine on a flat surface
Machines with automatic transmission must be in the “Park” position while those with manual transmission must have the first gear engaged. The handbrake must always be engaged.
Step 3. Remove the hubcaps and lift the car and secure it with brackets
Remove the four wheels.
Step 4. Open the hood and find the Master Cylinder fluid reservoir
It's a fist-sized (or larger) clear container screwed to the bulkhead on the driver's side. It is hooked to an aluminum object that of metal tubes coming out from the sides. These pipes are the brake pipes that carry the fluid to the individual wheels where they will actuate the disc or drum brake components that brake the car.
Step 5. Eliminate the old and dirty liquid in the reservoir
Fill it with fresh liquid making sure it is the right type for your machine. If in doubt ask for help when you are about to buy it.
Part 2 of 3: Bleeding the Brakes
Step 1. Go to the right rear wheel, clean the bleed screw area and remove the rubber plug
Use a wrench to loosen the bleed screw. Take a piece of a rubber tube and put it at the end of the bleed screw and the other end inside an empty plastic bottle.
Step 2. Hold the key while holding the bottle
Ask your helper to slowly squeeze the brake until the fluid comes out of the hoses and ends up in the bottle. Let enough liquid come out that the end of the rubber tube is immersed in the liquid. (Check the Master Cylinder continuously to make sure it is always filled with liquid.)
Step 3. When the brake fluid becomes clear tell your helper to keep the pedal pressed all the way down
Close the bleed screw with the key and tell your helper to press the pedal 3 times and hold it down. Open the bleed screw for a moment to let some liquid come out through the rubber tube. Get your helper to tell you when he holds the pedal all the way down and tell him to hold it as you close the bleed screw. Repeat the process 2 times. (Remember to check the fluid level in the Master Cylinder to prevent it from drying out) After the third time, tighten the bleed screw and repeat the process for the other wheels in this order: rear left, front right and front left.
Step 4. To make sure the brakes are not soft and that there are no leaks in the system, do this test when you have finished bleeding
With the engine off, ask your helper to press the brake pedal and check the wheels for leaks. Then you hit the brake pedal, it should move a few inches and stop and at that point it should be very hard.
Step 5. Get rid of excess brake fluid safely
Part 3 of 3: Testing the Brakes
Step 1. Refit the wheels and tighten the bolts
Lower the vehicle and tighten the bolts with a wrench. Refit the hubcaps if necessary.
Step 2. Take a test drive to see if the brakes are working properly
If there are still problems, have the car checked by a specialized mechanic.
Advice
- Prevents brake fluid from coming into contact with rubber or plastic parts.
- Follow safety procedures when lifting the machine.
- Bleed the brake lines every two years.
- Always keep the brake fluid reservoir full.
Warnings
- Use only the brake fluid indicated for the model and make of your car.
- Do not let go of the brake pedal until the bleed port is closed.
- Dirt particles can contaminate the fluid and cause brake problems.
- Brake fluid can dissolve the paint on the car.
