Learn how to change the brake fluids on your car

Brake Fluid - How to Change Brake Fluid

22 January 2015, 07:42

Brake fluid is a vital component to keeping you safe whilst driving. It enables the force created by pressing the brake pedal to be transferred directly to the wheel itself. This then allows you to slow down whenever you press the brake.

The heat which is generated from the friction caused by breaking can, over time, damage the brake fluid or turn it into vapour. This will prevent the brakes from working and can be extremely dangerous if you are driving at speed or in congested areas. Brake fluid also serves another purpose: it acts as a lubricant for moving parts and prevents things from rusting or seizing up. If your brake fluid is not in the best condition then it can affect different parts of the car and its performance overall.

Over a period of time, brake fluid can absorb water through small gaps in the joints of pipes and hoses and this can seriously affect the way in which it performs. This is why it is extremely important to regularly change your brake fluid, to make sure that your car is as safe as it

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How to change brake fluid

  • You should really have your brake fluid changed every two years. Any longer than that and the water content in the fluid is likely to be too high.
  • Before you replace the fluid you will need to flush the system. To do this you will need a container for the fluid you drain off, a spanner and a can of brake cleaner.
  • First, clean the main cylinder with the brake cleaner spray before you open it.
  • Next you will need to extract the old fluid. You can choose either the vacuum bleeding method or the pressure bleeding method to do this; in both cases you will probably have to buy a piece of equipment to help you do the job properly.
  • Once you have taken out the old brake fluid, fill the cylinder back up with the new fluid.
  • Make sure that you have purchased the correct one. Brake fluid is classified according to its boiling point. Most cars use DOT 4 or DOT 5.1 brake fluid but check which one you need before you put it in.
  • You will then need to raise the car slightly using a jack so that you can access each brake individually. You will need someone to help you by pressing the brake down slightly. When the pedal is pushed, open the brake bleeder valve for each wheel in turn and drain the old fluid into a container. As soon as your assistant presses the pedal all the way to the floor, close the valve to prevent any unnecessary moisture getting in.
  • Repeat this step for each wheel until the fluid you drain is clear. You may find that you need to go back and refill the master cylinder a few times in between.
  • Once you have done this for every wheel, pump the brake pedal 20 or 30 times to make the fluid level increase in the master cylinder.
  • If the brake warning light comes on once you have completed the process, pressing the brake pedal down quickly and firmly should make it go away.

Why is it important to replace your brake fluid regularly?

For brake fluid to do its job properly, it is important that it is not contaminated with any other substances. The presence of air or water in the fluid could be detrimental to the performance of the car. Neither air nor water can really stand the same amount of pressure as the brake fluid needs to withstand to do its job properly.

Different ways to empty fluid

There are different methods which you can use to effectively drain off the existing brake fluid. Pressure bleeding is probably the easiest as you can buy a pressure bleeder for a small amount of money and it will take a lot of the hassle out of the draining process. The vacuum method is just as effective but it can be more expensive to get hold of a decent vacuum pump and you will have to get one which is a good fit for the width of your master cylinder to make sure that it drains the fluid properly without letting air or water in.

Simple to do, but dirty and time consuming

Changing your brake fluid yourself is not particularly difficult. It is, however, a fairly messy and time-consuming job. The tools to do the job can be costly, even if the fluid itself is relatively cheap. If you are willing to get your hands (and probably most of your clothes) dirty, then doing the job yourself will save you money. However, your local mechanic will have all of the tools and knowledge necessary to do the job properly and you could use that time to do something more productive.

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