Driving with a Bad Master Cylinder – Is It Safe?

Driving with a Bad Master Cylinder is unsafe. It can result in poor brake performance, leading to issues like sudden stops. This increases the risk of brake failure, making it harder to control and maneuver your vehicle safely. It puts you, as well as other road users, at a higher risk of accidents.

So, it’s crucial to learn the symptoms of a bad master cylinder to address the issue quickly and promptly. Otherwise, this may end with a big impact. 

We’ll discuss the symptoms of a bad master cylinder, and how to fix it. We will also discuss the safety tips for driving with a bad master cylinder, and how to maintain your master cylinder to prevent it from failing. So, keep reading!

What is a Master Cylinder Do?

A master cylinder is a critical component that makes up your vehicle’s braking system. It functions as a command center, assisting you in securely stopping your car. 

Pressing the brake pedal converts the force generated into hydraulic pressure, which engages the brakes. This force causes the brakes to activate, slow, or stop the vehicle. 

The master cylinder consists of different components, such as a fluid reservoir and pistons, which work together to ensure proper braking performance. 

How To Know You Are Driving With Bad Master Cylinder? Symptoms

A vehicle’s braking system depends on the master cylinder. But driving with a bad master cylinder is unsafe. Here are the reasons why:

  • Bad master cylinders can compromise brake performance
  • Increased risk of brake failure
  • Unpredictable brake response
  • Longer stopping distances
  • Difficulty in controlling and stopping the vehicle
  • Higher risk of accidents and collisions
  • Putting the driver, passengers, and other road users at risk

Read Also: Air in Master Cylinder Symptoms – How to Detect & Fix It?

Dangers of Driving With a Bad Master Cylinder

Driving a car with a bad master cylinder can be very dangerous. A master cylinder is an important part of your vehicle’s braking system. When it doesn’t work properly, it can cause serious problems. Here are some risks you should be aware of

Poor Braking Performance: 

A bad master cylinder can make your brakes work poorly. Your brakes may not respond as quickly as they should when you need to stop your vehicle. This can increase the chances of accidents and make it difficult to control your vehicle.

Longer Stopping Distances

Having a faulty master cylinder can make stopping your vehicle more difficult. This means you need more distance to brake safely and this increases the risk of a rear-end collision or not being able to stop in time.

Read Also: Master Cylinder Failure After Brake Job: The Causes & Fixes

Brake Failure

If your master cylinder gets worse, your brakes may fail completely. This means you cannot stop your car at all, which is very dangerous. You may end up in a collision or lose control of your vehicle.

Loss of Control

Driving with a bad master cylinder can make your vehicle difficult to control. There is a possibility that your brakes may not respond consistently, making it difficult to navigate turns and avoid obstacles on the road. This can put you and others at risk.

Whenever you have problems with your master cylinder, it’s important to have them addressed by a qualified mechanic as soon as possible.

Read Also: Bad Master Cylinder or Air in Brake Lines? Find The Culprit

How to Fix a Bad Master Cylinder?

Here’s a step-by-step guide to help you fix your master cylinder if you are having issues:

Step 1: Diagnose the Problem

Ensure the master cylinder is indeed causing the problem before beginning any repairs. Look for symptoms like a soft brake pedal, brake fluid leaks, or spongy pedal feel.

Step 2: Gather the Necessary Parts and Tools

You will need a set of wrenches, a brake bleeding kit, brake fluid, and a replacement master cylinder if necessary. Make sure you have the right parts for your specific vehicle make and model.

Step 3: Set up the work area

Park your vehicle on a level surface and engage the parking brake. Open the hood and locate the master cylinder, usually located near the firewall on the driver’s side.

Step 4: Drain the Brake Fluid

As much brake fluid as possible should be removed using a turkey baster or syringe after removing the reservoir cap. Dispose of the old fluid properly according to local regulations.

Step 5: Remove the Old Master Cylinder

Remove the brake lines from the master cylinder by loosening them. Take note of their positions to ensure correct reinstallation later. Remove any mounting bolts or clips securing the master cylinder to the brake booster.

Step 6: Replace the master cylinder

Place the new master cylinder in place and secure it using mounting bolts or clips. Reconnect the brake lines, making sure they are securely tightened.

Step 7: Bleed the Brake System

Bleeding the brake system is crucial to remove any air trapped in the lines. Refer to your vehicle’s service manual for the correct bleeding procedure. Generally, you should start from the farthest brake caliper or wheel cylinder and work your way to the closest one.

Step 8: Refill with Brake Fluid

According to your vehicle’s manual, fill the brake fluid reservoir with the recommended brake fluid. Be sure to use a clean funnel to prevent contamination.

Step 9: Test the Brakes

Start your vehicle and pump the brake pedal a few times to build pressure. Ensure the pedal feels firm and responsive. Test the brakes at low speeds to confirm proper operation.

Cost Considerations

Depending on the make and model of the vehicle, the extent of the damage, and whether a repair or replacement is needed, the cost of repairing a bad master cylinder can vary. On average, a master cylinder replacement can range from $402 to $503, including parts and labor. If you want an accurate cost estimate for your specific situation, consult a trusted mechanic.

Maintaining a properly functioning master cylinder is crucial for your vehicle’s braking system. You will be more likely to be safe on the road if you address any issues as soon as possible.

Safety Tips for Driving With a Bad Master Cylinder

Driving with a bad master cylinder is not recommended, as it can compromise the safety of your vehicle’s braking system. If you find yourself in a situation where immediate repairs aren’t possible, it’s important to take certain precautions to ensure your safety on the road.

Here are some safety tips to consider:

Maintain Increased Following Distance

Increase the distance between your vehicle and the one ahead to allow for longer braking distances. This gives you a buffer in case your brakes don’t respond as expected.

Anticipate Stops and Slow Down Gradually

Plan your stops in advance and slow down to reduce reliance on sudden or sudden braking. This gives you more control over your vehicle and reduces stress on the braking system.

Avoid High-Traffic and High-Speed Situations

Whenever possible, avoid driving in heavy traffic or high-speed situations. These situations require frequent and effective braking, which can be compromised by a bad master cylinder

Be Mindful of Brake Fluid Levels

Check the brake fluid levels regularly to make sure they are within the recommended range. A low brake fluid level can cause poor master cylinder performance, so maintaining adequate levels is critical.

Listen and Feel for Warning Signs 

Pay attention to any unusual sounds or sensations while braking, such as grinding noises or excessive pedal travel. These symptoms may indicate further deterioration of the master cylinder and should be addressed immediately.

Schedule Repairs Promptly

While these safety tips can help mitigate risks, it is important to have your master cylinder repaired or replaced as soon as possible. Driving a vehicle with a compromised braking system is inherently unsafe, and requires professional repairs for long-term safety.

Remember, These tips are temporary measures, and it is important to seek professional repair to ensure the proper functioning of your braking system.

Master Cylinder Maintenance 

Proper maintenance and timely repair of the master cylinder are important to ensure optimal performance and safety of your vehicle’s braking system. How to maintain the master cylinder is given below:

  • Regularly inspect the master cylinder for any signs of leaks, damage, or corrosion.
  • Check the brake fluid level in the master cylinder reservoir and ensure it is within the recommended range.
  • If brake fluid appears dirty or contaminated, consider flushing and replacing it.
  • Check the brake lines and connections to the master cylinder for any signs of leaks or damage.
  • Make sure the master cylinder cap is tightly secured to prevent any contaminants from entering the system.
  • If you see any leaks, have the master cylinder repaired or replaced as soon as possible.
  • Follow the manufacturer’s guidelines for maintenance intervals and procedures specific to your vehicle’s master cylinder.
  • If necessary, consult a professional mechanic for proper maintenance and repair of the master cylinder.

Keeping your master cylinder properly maintained is crucial for the optimal performance and safety of your vehicle’s braking system.

Read Also: Brake Pedal Goes to Floor After New Master Cylinder – Why?


Now let’s look into some of the most common queries people have regarding bad master cylinders.

Can I fix a bad master cylinder myself?

It is recommended to have a professional handle master cylinder repairs because braking systems are complicated and important.

Can a bad master cylinder affect other brake components?

Yes, a bad master cylinder can potentially affect other brake components.

Can a bad master cylinder cause the brakes to lock up?

Yes, a malfunctioning master cylinder can lead to brake lock-up, where the brakes engage and stay applied even when the pedal is released.


Driving with a bad master cylinder poses a serious safety risk, effectively compromising your ability to stop your vehicle. By familiarizing yourself with the symptoms and following the provided safety tips, you can mitigate these risks and ensure a safer driving experience.

To maintain a healthy master cylinder and overall brake system, regular maintenance, and prompt repairs are important. Take good care of your vehicle’s braking system to ensure your safety and that of others on the road.

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