Signs and Symptoms of a Bad Master Cylinder in a Vehicle | Autance

The master cylinder is the most critical component in your care brake system because it enables your car to work effectively. When you step on the brake pedal to slow down your vehicle, the brake system uses it to transform the physical pressure into mechanical and hydraulic pressure. However, it is subject to failure like…

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Signs and Symptoms of a Bad Master Cylinder in a Vehicle | Autance © Signs and Symptoms of a Bad Master Cylinder in a Vehicle | Autance

The master cylinder is the most critical component in your care brake system because it enables your car to work effectively. When you step on the brake pedal to slow down your vehicle, the brake system uses it to transform the physical pressure into mechanical and hydraulic pressure.

However, it is subject to failure like other components in the vehicle. So, what are the common signs and symptoms of a bad master cylinder? This question will be tackled in detail later in the article, but first…

We have listed top 5 best Master Cylinders in the market at the comparison below:



Further information

ACDelco 18M1878

- Brand: ACDelco
- Item Dimensions: 9.4 x 5.8 x 4.8 inches
- Item Weight: 1.4 pounds
- Meets the brake performance requirements of SAE J1153 and J1154 testing
- Cast iron and aluminum specifications; no extra stress on the brake boosting mounting
- Geometrical tolerance ensures that the body and plastic reservoir match for a proper fit
- Piston assembly and return spring help to prevent brake drag

Cardone 13-2867

- Brand: Cardone Select
- Item Dimensions: 9.5 x 6.63 x 5.38 inches
- Item Weight: 2.42 pounds
- Only O.E.-quality seals and cups are used to ensure O.E. performance and reliability
- All rubber components meet S.A.E. specifications
- Bores meet critical micro-finish specifications to eliminate pitting and corrosion
- Castings feature a premium protective coating to minimize corrosion and extend unit life
- Seals are temperature-cycled from -30°F to +220°F

Wilwood Master Cylinder

- Brand: Bryke Racing
- Item Weight: 1.65 pounds
- Quality high volume Wilwood 3/4" Brake Master Cylinder. High volume, die cast aluminum master cylinder holds 8.2 ounces of brake fluid.
- 26% more fluid capacity than other master cylinders
- Includes formed steel lid, bellow type gaskets, internal slosh baffles, and standard mounting dimensions
- 1/8" NPT single outlet.
- The 3/4" master cylinder is the recommended size for most throw-out bearings.

Kawasaki ATV

- Brand: WorldPac
- Item Dimensions: 8.25 x 3.5 x 3.25 inches
- Item Weight: 1.35 pounds
- 10mm Clockwise Mirror Mount
- Full Cast Metal Construction with Sigh Glass
- Straight Level, Side Mount Outlet Facing Handlebar
- 2 Prong Wire Brake Connection

CNCMOTOK New Hydraulic Brake

- Item Dimensions: 7.6 x 5.6 x 4.4 inches
- Item Weight: 1.65 pounds
- 100%brand new Aluminum
- Brake pedal bolts spacing: 20mm,cylinder mounting bolts spacing: 60mm
- Compatible with Roketa American Sportswork Baja Kindi Sunl Hammerhead Twister Kinroad BMS.

What is a Master cylinder?

It is a very significant component in your car braking system. It plays a vital role in terms of the safety and performance of your vehicle. It is the primary mechanism of the braking system that is activated by pressing the brake pedal.

It pushes the fluid through the lining to enable the calipers squeeze the pads against the rotors. Its principal function is to push the metal rod through the cylinder to propel the fluid to the wheels through the braking system.

5 symptoms of a Bad Master Cylinder

You can start to notice the signs when it begins to break down. Another symptom that you can recognize easily is wear and tear. It is extremely dangerous to drive your car without proper brakes because you can be at risk of a severe crash.

If you suspect any problem with it, address the issue promptly to prevent any possible accident. Some of the symptoms of failing master cylinder include:

Constant Warning Headlights

A sensor is located beneath the brake fluid reservoir, which shares relevant information with your vehicle’s dashboard computer. It informs that there is sufficient or insufficient fluid in the reservoir. Thus, turning on the warning light in your on-board.

When warning lights irradiate on your car’s dashboard, this is the first typical sign of a severe problem in the braking system. If the sensors detect a drop in brake fluid pressure, it can indicate your master cylinder is faulty. 

Consequently, if the ABS car lights are always on, there might be fluid leakage into the braking system. Therefore, if you realize you are adding brake fluid constantly to your reservoir, your cylinder has a problem.

Leakage of the Brake Fluid

There is a certain amount of fluid needed to generate hydraulic pressure to slow down your car. Therefore, if you have a leak, it is one of the symptoms of a bad brake master cylinder.

This is an indication that your car doesn’t have sufficient fluid to get your vehicle to halt. To salvage this situation, you need to replace the master cylinder immediately before it impairs the capability to slow down your car.

Tainted Brake Fluid

Worn-out rubber seals are also a symptom of a faulty cylinder. The secure connection can be impaired if the rubber seals break down. The function of the seals is to prevent the brake fluid from pouring out and inhibit debris and mud from mixing with it.

Therefore, the damage of the secure connection can result in its contamination. The brake pedal then starts to be mushy and begins to fall off to the floor. This diminishes hydraulic pressure, and it becomes difficult to stop your car.

Soft Brake Pedal

Another symptom of a bad master cylinder is when you feel that your brake pedal is soft. This shows that it is faulty. The fluid inside it is kept tight by a rubber seal.

If these rubber seals are destroyed, it causes internal fluid leakage, resulting in a soft brake pedal, making it hard for your car to stop. A soft pedal increases the cost of purchasing a new cylinder.

Depressed Brake Pedal

When the braking system is functioning effectively, you feel the pedal when you step on it. So, when the pedal is returning to the top, after lifting your foot off the pedal, then it shows that it is damaged. It starts to sink into the floor; then, it is a sign that your cylinder is damaged.

Sinking pedals remain very close to the floor, but that relies on the damage of your master cylinder. Never drive a vehicle with a sinking pedal because you can be putting your life and that of your passenger at risk. To solve this issue, take your car to a professional mechanic for a proper check-up.

How Does Master Cylinder Work?

Its primary function is to transform the brake pedal mechanical pressure to hydraulic pressure. You can achieve this by pushing fluid into the braking circuit. Its main function in the drum brakes is to regulate the amount of fluid flowing to the circuit, and this is dependent on the amount of pressure exerted on the pedal.

All vehicles should be equipped with at least two diverse braking circuits. So, it creates the hydraulic pressure required by the circuit. This allows one of them to have enough pressure to sustain all its functionalities in case the other circuit becomes faulty.

The piston pressure receives intense pressure you exerted on the brake pedal, pushing the piston close to the brake lining. In most modern vehicles, there is a spring that provides necessary support to the pressure piston. 

As a result, the pedal resumes its original position when you remove your foot from the brake pedal. The brake fluid then returns to the master cylinder. Therefore, the next time you exert pressure on the pedal, pressure increases again.

The Best Master Cylinder for Vehicles

1. ACDelco (18M1878) Master Cylinder

ACDelco is a famous brand known to manufacture brake cylinders. ACDelco (18M1878) is made from sturdy aluminium and iron castings. So, there is no need to stress yourself to mount a brake booster. This product meets all the SAE requirements; thus, it gives you outstanding reliability and enhances the quality of your braking system. 

The pressure is tested to enable you to have a confident and safe halt while driving. It has geometrical tolerance that ensures that both the plastic reservoir and cylinder body match and fit correctly. It comes with a return spring and piston assembly to prevent the brakes from dragging, and dragging causes premature wear and tear of brake pads.

Tested pressure for safe braking
It’s made from both iron and aluminium casting
Return spring and piston assembly inhibit brake drag.
Geometrical tolerance
It meets all the SAE requirements

2. Cardone New (13-2867) Master Cylinder

Cardone New (13-2867) is an original piece of equipment that gives your car a safe brake while driving. High-quality cups and seals ensure reliability and excellent performance. It has bores that meet micro-finish qualifications to eradicate corrosion and pitting, leading to premature brake failure. Its casting has a quality protective coating to reduce the possibility of rust and increase its lifespan.

 For a steadfast performance as you drive your car, the seals are cycled under certain temperature conditions (from -29°F to +225°F). The plastic reservoirs are properly vacuumed to prevent leakage. It comes with the bleeding kits and installation hardware to fasten the bleeding and mounting process.

Superficial bleeding and installation process
It has a protective coating to minimize rust
High-quality seals and cups
Not cheap
It can leak if overused

3. Wilwood Wilwood Master Cylinder

Wilwood is famous for manufacturing high-quality master cylinders. It has a high volume that can hold approximately 8.5 ounces of brake fluid. It helps keep the fluid cooler because it can hold about 27% more fluid than other cylinders.

The package comes with standard installation dimensions, bellow gaskets, quality steel lid, and internal slosh baffles. It is big enough to minimize the pressure exerted at the caliper. This ¾ brake master cylinder is the best for throw-out bearings.

Premium high volume cylinder
Cools the brake fluid
Recommended for various throw-out bearings 

4. Kawasaki ATV (Black Housing) Cylinder

Kawasaki ATV is the best aftermarket cylinder. It is constructed with a complete cast metal that contains Sigh glass. It has a 10mm clockwise mirror installation that allows to fix it quickly.

You should always check the latest configuration, such as the side mount outlet and straight levels. It has two pong wires for connecting the brakes. Therefore, it enables you to halt with confidence anytime.

Greatly Reliable
Relatively cheap
Easy to install
Can be modified
Suitable for front brakes

5. CNCMOTOK Hydraulic Master Cylinder

This is a high-quality product from CNCMOTOK stores. It is made of premium aluminium material. The spacing of brake pedal bolts is about 15 to 20mm while mounting the cylinder is about 55mm to 60mm.

It comes with a plug for deep pocketing, and rubber parts consist of OE premium standards. The aluminium materials are anodized to enhance their strength. It comes with a lifetime warranty.

It fits many vehicles
Premium aluminium materials
Has plug for deep pocketing
Relatively expensive

The Cost of Replacing a Master Cylinder

If yours is damaged, then it can cost much higher than you may think. It price ranges between $300 to $500. The price of the parts can cost you around $150 to $230. The average cost of fixing the cylinder ranges between $200 to $320.

You can save yourself a lot of money if you have the relevant skills and tools required to fix it. But, this is possible if only you are a professional mechanic. Nevertheless, it is a very challenging job that requires a lot of experience. Therefore, take your car to a skilled mechanic as soon as you recognize any master cylinder symptoms.

Commonly Asked Questions

How much will it cost me to replace a faulty master cylinder?

Replacing it can be challenging, although it is not an expensive thing. The bulk relies on several factors such as cost of labor, car parts, model and makes of your car, and other services that might be provided during the replacement. The cost of replacement can also be affected by the amount of work done during the repair. You can browse through several websites to help you determine the cost of replacing a damaged cylinder.

My brake pedal goes to the base; what might be wrong?

You need to check your braking system if you are experiencing such a problem. The most common cause of a depressed brake pedal is a faulty master cylinder, damaged brake booster, or loss of brake fluid. 

Sometimes, when there is hydraulic pressure loss, the brake pedal goes down to the base. The braking system uses compressed fluid flowing through the circuits hence applying brakes to your car’s wheels. Therefore, the loss of this pressure and fluid causes your brake pedal to fall off.

How can I go about changing my master cylinder?

It is challenging to replace it, but you can do it in two ways. You can either seek assistance from a professional mechanic or do it yourself. If you choose the latter option, then you need to have the quality and the right mechanic equipment. Follow the steps below if you want to replace it yourself:

  • Remove the damaged master cylinder
  • Then bench bleed it
  • Mount the new one

How can I solve the issue of a falling brake pedal?

A depressed pedal is one of the many symptoms of bad brake master cylinder. First, you need to address the problem leading to this situation to fix the falling brake pedal. The internal seals are prone to damage if overused.  

Thus, air can enter the braking system if fluid bypasses backward into the reservoir, causing leakage. Therefore, sinking occurs due to inadequate brake fluid. The perfect way to solve this situation is to change it.

Bottom Line

It is not wise to overlook the symptoms of a bad master cylinder.So, if you notice any of the symptoms mentioned above, seek the assistance of a professional mechanic. Servicing your car prolongs its lifespan and can serve you for a long.

It enables the braking system of your car to operate smoothly. Ensure you replace the bad one with any of the products listed above for confident and safe braking. Remember, if you ignore any of the symptoms, you put yourself, passengers, and other road users at risk of a serious accident.

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