The Brake Fluid Flush: All you need to know. | AG Automotive

Whether you drive a car from the 1970’s or a brand new electric semi truck, they all use the same process to slow the vehicle down and come to a stop. When a brake pedal is pressed down, friction is applied to a vehicle’s rotating wheels to slow it down and eventually come to a complete stop. The process of braking is accomplished by either a drum brake or disc brake system that is located just behind each of the four wheel’s rims. The systems are vastly different in their ability to brake the car, but besides the commonality between the two, they also both produce heat as a byproduct of friction. 


Brake fluid is an integral component of each of the braking systems because it provides the hydraulic pressure and force needed to activate each braking system. We will uncover the difference between the two braking systems in the sections below.  


If you have any questions or concerns regarding your vehicle’s braking system or brake fluid, call AG Automotive and schedule an appointment with our team of expert automotive technicians today!


What’s the difference between drum brakes & disc brakes:

  • Drum Brakes


Drum brakes were installed and used on all four wheels during the earlier years of vehicle manufacturing and production. The name “drum brake” comes from its components. The braking system is housed in a round drum that rotates along with the wheel. When the brake pedal is pressed, brake fluid is transferred to a set of shoes via hydraulic pressure that squeezes them against the drum- creating the friction needed to slow a rotating wheel down to a stop.  


One common problem with drum brakes is for them to experience brake fade, which causes the drum brakes to lose effectiveness and braking capabilities. This happens when a vehicle is carrying a heavy load or is constantly having to slow the vehicle down. Constant braking results in a high amount of generated friction, in turn, creating a massive amount of heat. The heat energy created by the friction is transferred to the drum. Thermal expansion slowly decreases a brake pad’s ability to clamp down on the rotating drum because of the change in tolerances. Thus, the performance and stopping ability of drum brakes relies heavily on its ability to absorb and transfer heat efficiently and effectively away from the drum to ensure brake fade doesn’t happen. 

  • Disc Brakes


Disc brakes also rely on the same principle of using friction to slow a vehicle, but are far more advanced in their overall braking performance and capabilities. Instead of using a drum that rotates with the wheel, disc brakes use a rotor and caliper to slow the vehicle down. The brake caliper sits on the rotor and sandwiches it between a pair of brake pads. When the brake pedal is pressed, brake fluid is transferred to the set of brake pads via hydraulic pressure that clamps them against the rotor- creating the friction needed to slow a rotating wheel down to a stop. 


One major advantage that disc brakes have over drum brakes is that they are fully exposed to the outside air instead of being protected by a metal housing. This means that disc brakes are way more effective at absorbing and transferring the heat generated by friction to greatly reduce brake fading and overheating. Over time, vehicle manufactures started to move away from drum brakes because of how much more effective and safer disc brakes were to use. 


What is brake fluid?


Brake fluid is a liquid composed of chemical agents designed to enhance the hydraulic power generated by the braking system. Its purpose is to greatly amplify pressure applied to the brake pedal and transfer the pressure to a vehicle’s drum or disc brakes. 


Did you know that clutch fluid is really just brake fluid that is kept in the clutch master cylinder? We call it clutch fluid based solely on its location. When you press down the clutch pedal, the clutch fluid flows from the clutch master cylinder to the slave cylinder. The pressure that is created by this transfer of fluid is used to engage the clutch, which then allows you to change gears. 


See our blog about AG Automotive’s clutch fluid exchange service for more information about a vehicle’s clutch fluid. 


Why a brake fluid exchange service is needed:


  • Loss of brake fluid due to leaks or evaporation 
  • Air is trapped inside the brake lines
  • Contaminated or old brake fluid


Brake fluid typically lasts anywhere from two to five years depending on the model and use of the vehicle. 


Common warning signs of a brake system malfunction:


  • Brake fluid should be clear or at least translucent, if you notice a brown color, it is contaminated and requires a brake fluid flush to replace all of the old brake fluid with clean brake fluid.
  • Loss of braking ability typically means there is air within the hydraulic lines created by evaporation or a leak, this means you should have a brake line bleeding service to get all of the air out or lines replaced.
  • Brake fluid level is low due to evaporation, leak or excessive wear on your brake pads. Worn brake pads means there is a greater gap between the pads and rotor, requiring more brake fluid to flow through the lines, ultimately decreasing the effectiveness of the hydraulic system.  
  • A puddle has formed underneath your car 


AG Automotive offers different braking system services:


  • Brake Line Bleeding Service
  • Brake Fluid Flush Service
  • Brake Fluid Leak Repair Service


Schedule a brake fluid exchange service with our expert mechanics at AG Automotive today!


If you have noticed that your vehicle doesn’t brake like it used to, your check engine light is on, or a puddle has formed under your car, Ag Automotive will have you back on the road in no time after we identify that your vehicle needs a brake fluid exchange service. Our expert technicians have the tools and knowledge to replace your brake fluid or replace important components quickly and efficiently.


We want the job to be done right the first time, so we ensure your braking system works properly and exceeds the manufacturer’s specifications after our service is complete. We offer our customers a full service inspection and service of their braking system so they can get back out on the road and drive with confidence knowing their vehicle was serviced by the best. 


We offer our customers a full-service brake fluid exchange which includes:


  1. Visually inspect brake hydraulic system for leaks
  2. Visually inspect brake lining (Does not include pulling wheels)
  3. Clean our master cylinder reservoir
  4. Flush complete brake hydraulic system
  5. Adjust brakes (If applicable)
  6. Adjust park brake including internal adjustment (If applicable and accessible)
  7. Clean and test drive
  8. Check for proper brake function
  9. Recheck fluid level and for leaks
  10. Quality Check
Don’t Second-Guess the Condition of Your Vehicle

Many auto owners struggle to know if the right work was done the right way on their car. As a courtesy, we provide digital vehicle inspections and photos so you can quickly and easily see what our experienced, professional technicians are seeing. Overall, we go the extra mile to help you make informed decisions on the repair and maintenance plan of your vehicle, so you can drive with confidence every time you get behind the wheel.