Many car owners are aware that one of the most critical repair facilities the car needs is to adjust fuel oil for the vehicle. While it’s real, that oil saves your engine from catastrophic circumstances, there are other plenty of fluids in your car that serve a very important function that keep your car running optimally.

What are the most essential fluids for car maintenance?

  • Power steering fluids
  • Coolant
  • Transmission fluid
  • Brake fluid

Here we elaborate only about why is a brake fluid flush necessary? And why it so important to check and change fluid at an appropriate time?

Brake fluid is important, so you wouldn’t be able to stop your car without it. Many cars today are fitted with hydraulic braking systems that allow fluid to build up pressure and stop the vehicle gradually.

How Brake Fluid Works?

Brake fluid is an integral part of the hydraulic brake system. Brake pressure forces fluid to the brakes, causing the pads to clamp down on the rotors, attached to the wheel hubs that spin as the wheel turns. The high pressure causes the car to slow down.

Without any brake fluid, no pressure can be created to stop the car. Brake systems are completely sealed to assist in creating pressure. If there is a leak in the system, and the vehicle is losing brake fluid, your brakes will not be able to function well, or at all. Brake fluid leaks can be very dangerous and for safety’s sake, it’s best to avoid driving the vehicle until a professional can fully inspect the system.

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When to replace brake fluid/flush is required?

Typically there is no strict requirement that you should change at a specified time after a certain miles driven or change brake fluid after 2 or 3 years.

It basically depend upon certain factors and symptoms that would tell us about the right time to change brake fluid/flush, sometimes you only needed to fill the brake oil in a located bottle to a level recommended on it or just need to bleed after certain period of time.

For normal circumstances when you feel that you do have to push pedal harder to brake, which hadn’t been in the past.


  • We suggest flushing your brake fluid once a year, Hard breaking on the brake rotors accumulates a lot of heat in the brake system and “boils” the fluid creating air bubbles. Bleeding your brake system helps get rid of those air bubbles in the system.

For both bleeding and flushing your brakes, it’s recommended to have fresh brake fluid readily available. If the fluid in the reservoir runs low while bleeding/flushing, it will induce air into the system making rendering the entire process useless.

Make sure the brake fluid is fresh and hasn’t been sitting on the shelf more than 3 weeks if the seal has been opened. This is important as opened brake fluid is going to contain moisture. Unlike other brake components such as brake rotors or brake pads, brake fluid is sensitive to shelf life, especially when opened.

However other conditions that only filling the bottle and bleeding do not resolve the issue, then here are the reason for that.

  1. Those issue are here as follows.
  • When brake fluid ages and is polluted with small debris, the fluid’s boiling point descends, In extreme cases, it can lead to the brakes not working at all.
  • ABS and traction control are critical safety devices that focus on clean brake fluid, since the heat they produce shortens the brake fluid’s life.
  • Brake oil is continuously dropping after a certain miles driven without noticing any above symptoms, then it could be Oil leakage or your vehicle Brake pads life are at an end stage.

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  1. How to Check Brake Pads Life?
  • Hear the brakes when you hit a halt. Many brakes are fitted with squealers which will show when the brake pads start wearing thin. If the brake pads get too thin, these squealers can emit a loud, high-pitched sound.
  • If you push the brake down to the floor but your car doesn’t come to an immediate stop, your brake pads might be worn down.
  • A pulsing or vibrating brake pedal can cause the rotors to be deformed. A mechanic will be in a position to better assess the problem.
  • Pulling on one side when you come to a stop is a warning that one side of the brakes is more damaged than the other. If you find your car pulled to one side after pushing the brake button, check the front tyre on that side to make sure the brake pad is not worn off


  1. How To Inspect brake fluid oil is leaking?
  • Dripping on the Floor: The past few mornings you’ve noticed spots of a light yellow to brownish fluid under your vehicle, near the wheel. You reach down and touch the spot; the fluid leaves a slippery residue on your finger.
  • Brake Warning Light On: Sometimes it turn on at a later stage but that also a sign of having a problem.
  • Brake Pedal Feels Squishy: When you push down on the brake pedal to slow down or stop your car, it should feel firm with only a small amount of travel before your brakes are engaged. If instead the brake pedal feels soft, mushy, spongy, or squishy, it’s likely the result of air getting trapped in your brake lines.
  • Brake Pedal Goes Down to Floor: This often occurs alongside your brake pedal feeling soft or squishy. When you have a severe brake fluid leak or problem with the brake master cylinder, you will experience what some call “brake pedal sink”.


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How to Inspect Brake Fluid level?

  • Let the car cool it down.
  • Locate tank braking oil. Your owner’s manual will provide you with a precise location for your particular car. It is normally situated on the driver’s side between the engine and the door, near the wall.
  • Compared to other reservoirs, the brake fluid reservoirs are comparatively small, and have a screw cap on top. It may or may not have brake fluid written on the bottle, so it should have directions on the bottle or tank, or both. These directions inform you what sort of brake fluid to use and how to clean the rim.
  • Cleaning off the cap to the brake fluid reservoir before opening helps to prevent debris from going into the reservoir including moisture which can make your brakes less efficient and eventually corrode the interior of your brake system.
  • Twist off the cap, locate the dipstick and wipe it clean with a dry rag. Screw it back on and then remove and look at the dipstick. The line should be somewhere between the “add” and “full” Add brake fluid if needed. 

How to Flush Brake Fluid?

For flushing brake fluid, you have to has an appropriate experience and required tools needed to complete that task, we recommended you to take an assistance from car mechanic expert.

However for knowledge, how it is done? Here are following steps.


  • Car jack
  • Jack stands
  • New brake fluid
  • Adjustable wrench
  • Hand-held vacuum pump (if you don’t have one, you can also use a turkey baster)
  • Rubber hose
  • Plastic container
  • Safety gloves and protective eyewear
  • Rags
  • Rock or block of wood
  • An assistant

How To do it?:

  1. Park your car on a safe and level surface. Set the car in gear and put a rock or a block of wood behind the tires to keep it from rolling.
  2. Make sure you wear your gloves and safety eye wear.
  3. Open the hood and find the master cylinder containing the brake fluid. This is usually labeled.
  4. Open the master cylinder cap and place some rags around it to prevent spillage (brake fluid can ruin your car’s paint). Using the vacuum pump or baster, suck out all the old brake fluid.
  5. Refill the master cylinder up to the fill line with new brake fluid.
  6. The caliper you will bleed first will depend on your car’s manufacturer. Generally though, it’s the furthest caliper from the brake reservoir. So if the reservoir is in the engine bay on the passenger side, you would start with the driver’s side rear caliper first. Double-check with your manufacturer to be sure.
  7. Loosen the bolts on your wheels.
  8. Jack up the car and place it up on a set of jack stands.
  9. Remove the bolts and wheel of the caliper you’re going to bleed.
  10. Locate the bleeder valve and plug the hose over it. Place a container on the other end of the hose to catch the fluid.
  11. Using an assistant, have him/her pump the brakes about 4-5 times and they should notice it get stiffer. While they are holding the brake pedal down, open up the bleeder valve and fluid will come out. The trick is that you want you’re assistant to notify you to close the valve right before they hit the bottom of the brake pedal.
  12. Repeat this process until fresh brake fluid comes out. Usually old fluid is darker and you will notice the shift to a lighter fluid indicating the fresh fluid has filled that brake line.
  13. Repeat the same process for the remainder of the brake calipers and make sure that the brake fluid never gets below the minimum marker on the master cylinder. If this happens, you risk getting air into the system again and having to re-do the entire process again.
  14. Once all four corners are done, top of the fluid in the reservoir to the max line, torque the wheel bolts to proper specification and verify you have a solid brake pedal feel before driving.

About The Author

Avatar for Ibrar Ayyub

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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