Which Is The Front Brakes On A Master Cylinder?

The master cylinder increases braking force on the pedals, which helps stop your vehicle. But which is the front brakes on a master cylinder, and which one is the back brakes? Find out this and much more!

Modern vehicles can run at very high speed. So there is a need for efficient braking force to stop the car. Mechanical brakes cannot generate sufficient force to stop vehicles which run at such high speeds.

This is why hydraulic braking systems are so important. The Master cylinder is one of the critical components of the hydraulic braking system.

Whenever you apply the force on the brake pedal, it is hardly 50-70N (N= Newton, it is a unit of force applied), which is not enough to stop super and hyper series vehicles used today. 

The master cylinder converts the mechanical force applied by the driver into hydraulic pressure. It generates a much higher braking force, making it easier for the driver to stop the vehicle at the desired location.

One query that people often have is about which part of the master cylinder handles which brakes (front or rear). We will talk about this and also explain the working of a master cylinder in more detail. So, keep on reading the article for more information.

Which Is The Front Brakes On A Master Cylinder

Which Side Master Cylinder is Front Brakes?

So, which are the front brakes on a master cylinder? Well, it depends on the braking design of your vehicle. 

In some vehicles, the first section of the master cylinder, which is closer to the brake pedal, will handle the front brakes, and the second section will handle the rear brakes. In this case, the primary chamber or the dual or tandem master cylinder help in stopping the front wheels of your vehicle.

In other vehicles, you may find a dual diagonal setup where the right front and left rear brakes are in one hydraulic circuit, and the left front and right rear brakes are in other circuits. 

This was the answer for the experts of automotive design out there. For everyone else, keep reading the article to understand what a master cylinder is, and then come back to read this answer.


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What Is a Master Cylinder?

The Master cylinder is the primary component in your vehicle’s braking system. Whenever you apply force on the brake pedal, the brake fluid enters the master cylinder and is compressed to high pressure. 

The science behind Master Cylinder

The master cylinder works on the scientific principle known as Pascal’s law, which states that:

  1. Pressure applied on a liquid is equal everywhere.
  2. Force exerted by the liquid on an external surface is proportional to the area of the surface of contact.

Put simply, this means that if you have an area 10 times larger, the force applied by the liquid will also be ten times larger. Hence a small 50-70N force applied by you becomes a larger force on the brake, because the area of contact is much larger

The high-pressurized brake fluid goes to the brake caliper. The brake fluid exerts an equal amount of pressure on the brake caliper’s pistons.

The piston is attached to the brake pads. They are steel plates and have friction material that directly contacts the disc or rotor. The rotor is the vital component of the disc brake and is attached to the wheel’s wheel hub. You will find so many vents on the disc brake, which help dissipate the heat generated on the disc’s surface.

The pressure exerted on the piston will apply pressure on the brake pads, and consequently, it is moved towards the rotating disc or rotor. It generates a lot of friction between the disc and brake pads which is sufficient to stop your car.

Which Is The Front Brakes On A Master Cylinder

How Does A Master Cylinder Work?

Most modern vehicles now have tandem master cylinders which means you will find dual cylinder and dual-piston arrangements or single cylinder and dual-piston arrangements in the master cylinder.

The tandem master cylinder is more efficient compared to the single master cylinder. You can apply brakes independently, i.e., one hydraulic control controls your vehicle’s front wheel, and the other circuit controls your car’s rear wheel.

Parts Of Tandem Master Cylinder

#1. Reservoir(s)

In a single master cylinder, there is only one reservoir. But in a tandem cylinder, you will find two reservoirs for storing brake fluid. The reservoirs are made up of plastic.

#2. Cylinder

There is a cylinder in a tandem cylinder, just like a single master cylinder. But here, the arrangement is slightly different. There are two pistons and two inlet and outlet valves inside the cylinder.

#3. Piston

There are two pistons inside the cylinder of the tandem master cylinder, i.e., one is a primary piston, and the other is a secondary piston.

The primary piston connects to the brake pedal, and the second piston is found behind the return spring of the primary piston.

#4. Returning Spring

You will find two coil structures found in the tandem cylinder. One returning spring is used for the primary piston, and the other is used for the secondary piston.

#5. Valves

There are two inlet and outlet valves in the master cylinder.


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Working Principle of Tandem Master Cylinders

The working principle of the tandem cylinder is almost the same as that of the single-cylinder master cylinder. But here, you will find two hydraulic circuits instead of one.

Initial position

When the brake pedal is not pressed, the piston is in its original position. The inlet valve of both the chambers is closed, thus preventing the brake fluid from entering the reservoir.

Brake Fluid enters Primary Chamber

Now when you press the brake pedal, there is the movement of the primary piston. So, the inlet valve is opened, and the brake fluid starts entering the primary chamber. The brake fluid is compressed inside the primary chamber, which increases pressure.

Which Is The Front Brakes On A Master Cylinder

Brake Fluid Applies Force On Front Brakes

A point comes when the pressure of the brake fluid becomes so high that the outlet valve opens, and the brake fluid moves towards the caliper by brake lines and finally stops the vehicle. The primary chamber mainly controls the front wheels of the car.

Secondary piston

The secondary piston starts moving after the completion of the movement of the primary piston because of the force applied by the primary return spring. 

Secondary chamber valve opens

It helps open the inlet valve of the secondary chamber, and the brake fluid starts entering the secondary chamber. The brake fluid is compressed, and its pressure is increased. 

Brake Fluid applies force on the Rear Brakes

Finally, a point comes when its pressure is so much more than the outlet valve of the secondary chamber will open, and brake fluid flows towards the brake caliper and stops the vehicle. The secondary chamber usually controls the rear wheels of your car.


Here’s a video that explains how the master cylinder works:



Nowadays tandem master cylinders are used in most cars that are equipped with a hydraulic braking system. The main benefit of using a tandem master cylinder is that if there are issues in one of the chambers, the other chamber of the master cylinder will help stop your vehicle.


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Frequently Asked Questions

#1. Which master cylinder reservoir is for the front brakes?

The dual master cylinder has two reservoirs, i.e., a primary and secondary reservoir. The primary reservoir is mainly for the front brakes.

#2. Is there a front and back on a master cylinder?

Yes, in a dual master cylinder, you have two chambers. The primary chamber controls your vehicle’s front brakes, while the secondary chamber controls the rear brakes of your car.

#3. How do you hook up a master cylinder?

  • Locate various components of your vehicle braking system. You can study the manual properly, which will help you identify multiple components. You will find the master cylinder just beneath the fluid reservoir.
  • Remove the brake fluid from the brake fluid reservoir.
  • Remove the brake fluid sensor connector.
  • Remove the brake fluid lines.
  • Now identify the master cylinder. Now take a wrench and remove the bolts from it. You can now remove the old master cylinder by your hand.
  • Install the new master cylinder and tighten it with bolts.
  • Fill the reservoir with brake fluid.

Which Is The Front Brakes On A Master Cylinder

#4. Why are there two brake lines coming out of the master cylinder?

One brake line comes from the primary chamber of the master cylinder to stop the front wheels of your car.

The second brake line comes from the secondary chamber of the master cylinder to stop the rear wheels of your vehicle.

They are designed for safety measures so that if one brake line has leaking issues, then the other brake line will help stop the vehicle.


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A Few Final Words

Brakes are pretty part of your vehicle. It helps in stopping your car at your desired location.

Most vehicles now have a hydraulic braking system. The master cylinder is the critical component in the hydraulic braking system. 

Earlier a single master cylinder was used, and it controls both the front and rear wheels of your vehicle. But if there are issues in the piston or spring or any other component in the master cylinder, it affects your vehicle’s entire braking system. You will have a problem stopping your car, which is quite dangerous. It may even lead to accidents.

But in a dual or tandem master cylinder, you will find two chambers, i.e., one helps stop the front wheel, and the other helps in stopping the rear wheel. So, if one chamber has any issues, the other chamber will help in stopping your car. It will even prevent accidents from occurring.

Thank you for reading, we hope you enjoyed the article. Let us know if you have further questions.

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Sean Mendez

Hi, I am Sean, a self-confessed petrolhead. I live in Boise, Idaho with a busy family of four and our energetic Labrador retriever. Thank you for visiting my website. You can find my email on the contact page.

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