Brake fluid is a hydraulic fluid that is used, along with transmission fluid and motor oil, periodically during a car’s maintenance.
‘Flushing’ is a term that’s used when old brake fluid is drained out of the brake calipers and new brake fluid is put in. ‘Bleeding’ is another term that is similar but has a different meaning.
Instead of completely replacing the brake fluid, a small amount is ‘bled’ out in order to remove air bubbles. Flushing and bleeding are both important procedures in the continued maintenance of an automobile.
The Cost of a Brake Fluid Change
The expense for changing brake fluid for your car is comprised of a few different parts and starts with the cost of the brake fluid itself.
Fluid prices vary depending on the volume of the container, brand, and type. Here is a list of some of the price ranges based on volume to give you some ideas:
- 12 oz: $3 to $13
- 16 oz: $22 to $25
- 9 oz: $10 to $26
- 1 Quart: $8
There are also 8 oz bottles available which only cost a couple of dollars or less. If you want to stock up on the stuff, you can buy 12×12 oz packs ranging from $27 to $150. There are tons of different brake fluid brands and you might want to pick one and stick with it. Here are some of the most popular brands just to give you an idea:
- Motul USA
- Lucas Oil
- Amalie Oil
- Champion Brands
Besides the brake fluid, the total cost will also include the labor charge if you bring the car to an auto shop.
Many modern car repair shops now use machines that automate the work of flushing out the brake lines. These machines work much faster than a person would and can complete the process in a shorter amount of time.
There’s still manual labor needed though, so a mechanic’s hourly rate is part of the labor fee. Changing the brake fluid will cost about $70 per hour as labor charges.
You can also try doing a brake fluid flush job by yourself, but it’s a lengthy and potentially messy operation. If you think you’ve got what it takes and want to save on the cost of the operation, we’ve included a section at the end of this article dedicated to helping you DIY.
What is Brake Fluid?
Simply put, brake fluid is what allows your car to slow down or stop when you press the brake pedal. When you push down on the pedal, brake fluid is rapidly pushed by pistons through a system of hydraulic lines which end up multiplying the force greatly.
The fluid finally reaches the brake caliper in the wheels, and the pressure forces the brake pads against the disc rotor which causes your car to slow down or stop, depending on how hard you hit the brake.
There are various types of brake fluids on the market made by different manufacturers. The most common are classified as DOT 2, DOT 3, DOT 4, DOT 5, and DOT 5.1. Only glycol-ether based brake fluids can be mixed together, but this is not recommended as fresh brake fluid should always be used when performing a flush.
DOT 2 is based on castor oil, DOT 3, 4, and 5.1 are glycol-ether based, and DOT 5 is silicone-based. The fluids are all either colorless, amber or in the case of DOT 5, purple.
Brake fluid is toxic and care should be taken not to let it drip on your vehicle as it will cause painted surfaces to become damaged.
Every car has a specific type of brake fluid that is recommended by the car’s manufacturer, so don’t worry about trying to figure out which to use. Always use the right brake fluid for your car and just make sure it’s high quality. It may cost more, but it’ll save you more in the long run.
What are Flushing and Bleeding?
These terms are sometimes used interchangeably and incorrectly so. There’s actually a difference between the two.
Flushing refers to the complete replacement of all brake fluid in the vehicle while bleeding is simply draining the calipers to remove some contaminated fluid. Most casual car owners, unfortunately, are not very familiar with flushing or why it’s important.
This may be in part due to the fact that even the manufacturers of the vehicles themselves only recommend flushing every few years. Some recommend replacing the brake fluid every 1 – 2 years while others set a mileage limit.
For example, Volkswagen says to flush every two years regardless of mileage. Mercedes Benz says every two years or every 20,000 miles, whichever comes first.
On the other hand, Subaru says there’s no time limit – just flush it every 30,000 miles. In stark contrast, Chevy says every 10 years or 150,000 miles. Porsche has its replacement time period pegged at 2 years. And yet, other manufacturers such as Ford, Toyota, and Chrysler do not list flushing as a regular maintenance item.
This goes to show that brake flushing is highly specific to the type of car itself, and certain types of brakes don’t need to have their fluid changed as often. Make sure to research yours and find out what the recommended brake fluid flushing period is.
Bleeding and flushing were traditionally done by hand. Finding that this process took too long, equipment was manufactured which could automate the process. Bringing your car to an auto center to have maintenance work done will result in a faster and more thorough procedure.
Why Brake Fluid Needs to Be Changed?
Once a vehicle’s reservoir has been filled with brake fluid, it’s usually good to go for the next few years.
However, there are certain situations in which the brake fluid in a car will need to be replaced or refilled. This typically happens when either the fluid inside becomes contaminated or begins to leak.
Contamination of existing brake fluid can occur in several ways. Brake fluid is ‘hygroscopic’, which means that it absorbs moisture from the air. This is bad because the hydraulic system is made up of many metallic parts and moisture in the fluid can cause damage over time to these parts.
Changing the brake fluid is relatively inexpensive. But if these metal parts become rusted or corroded, you will spend much, much more. In order to prevent getting moisture in the hydraulic system, always make sure to use a fresh bottle of brake fluid when topping off the reservoir.
When brake fluid is being pushed by the hydraulic system, it becomes very hot, almost to the point of boiling.
Moisture or water has a lower boiling point than the fluid, so what will happen is that the water will boil and create air bubbles that become trapped inside the fluid. This greatly reduces performance as the entire system relies on force and pressure.
Brake fluid can also become contaminated by small particles of debris or pieces of rubber that have broken off from the valves on the calipers or cylinders.
Once any foreign objects, no matter how small, have been introduced to the brake fluid, the brakes will not work at maximum efficiency and you might have a hard time pressing on the pedal or it might feel soft and ‘squishy’.
If you notice that the level of fluid in the master cylinder reservoir is dropping, this could be an indication of leaking in the hydraulic lines. The cause should be investigated immediately in order to discover where the excess brake fluid is going. Leaks will cause a loss of hydraulic pressure and make it very difficult to brake properly.