In light of recent news we here at Spectro Performance Oils wanted to share some information regarding brake fluid. Far too often when we talk to people about the intervals in which they change the fluids on their vehicles there is always one fluid that is left out. People change their engine oil based on mileage, or at least once a year. They will change their transmission oils on average every 2-3 years. They will even talk about swapping out their coolant, or suspension fluids…all before they even think about their brakes. There are three main factors to consider when it comes to your brake fluid and why you should change it on a regular basis; Compressibility, Corrosion, and Boiling Point.
Let’s start with Compressibility and how making sure you have enough fluid is important. Brake fluid has a very simple job in theory, it works in much the same way that a simple hydraulic system works. You apply pressure via a pedal or lever, the fluid then pushes the hydraulic piston at the other end of the closed system. The reason that this is able to happen is because brake fluid is not compressible. If you were to look at it from a molecular level, all of the molecules are so tightly packed that they cannot be pushed any closer together. The same cannot be said for air. The reason that you need to bleed brakes after doing a fluid swap, or when you get air introduced to the system is that the molecules in air/gases are not as densely packed. Thus when you apply force to the braking system the air will compress first before the system is able to push the piston. This can cause a “low pedal” where the brakes do not engage as quickly as possible, or in extreme situations the pedal or lever could completely depress without the brakes engaging at all. This is why it is always important to make sure your fluid level does not drop below the minimum threshold.
Corrosion is a major issue internally for braking systems. In order for hydraulic pressure to be applied in the braking system, the brake fluid needs to be able to flow freely throughout the system. Corrosion inside of the system can block off passages either by restricting flow due to narrowing of the pathway, or particulate that breaks off and plugs the system. The number one cause of corrosion is moisture in the system. DOT 3, 4, and 5.1 fluids are hygroscopic, meaning that they absorb moisture. You should only use brake fluid that is in a sealed container, as it can absorb water from the atmosphere under even standard humidity levels.
The boiling point of brake fluid is one of the least talked about characteristics of a brake fluid, but depending on how you use your vehicle it can be one of the most important. Brake systems are under immense pressure, and pressure creates heat. Combining that heat with the heat created from the friction of the external braking components and brake fluids can see temperatures well over 500 degrees in extreme, constant braking situations. The problem with this heat is that brake fluid like any fluid can vaporize into a gaseous state once it hits it’s boiling point. As we discussed in the compressibility section, gasses, unlike fluids are compressible. The result of heating your brake fluid past its boiling point quickly becomes the same as getting air in your system…little or no braking power. The other issue is that the boiling point of a brake fluid does not always remain constant. If a brake fluid becomes contaminated with water it can lower the boiling point of the system as water boils at a much lower temperature than brake fluid. This is why it is a good idea to change your fluid often and help maintain the durability of the fluid.
Next time you are changing your oil, flushing your coolant system, or even washing your car or motorcycle think of the last time you checked or replaced your brake fluid. Maintaining it is as simple as three easy steps. Keep your brake fluid level reservoir topped off. When adding brake fluid to your system only use fluid from a sealed container. Change your brake fluid on a regular basis. If you have any questions regarding the proper fluid level, what type of brake fluid to use, or how often to change it, check with your manufacturer who provides this information to help ensure that when you are out on the road you are safe and secure. We also created an acronym to make it easier to remember all the major points, because it’s nice to get out there and enjoy the ride, but at the end of it you also want to be able to come to a STOP!
||ealed containers only!
||op off fluid when low!
||nly follow manufacturer’s specifications!
||erform regular maintenance!