How to fix Hard Brake Pedal After Bleeding?

I remember my first experience with a hard brake after bleeding my 2005 Elise (about 30,000 miles). I was so baffled about what went wrong in the entire process.

Bleeding your brake line helps you eliminate air bubbles within the brake line. However, if done wrong, air may remain in the brake system, resulting in a hard brake pedal.

Luckily for our readers, you don’t have to go through what I did. I have compiled a simple do-it-yourself guide to help you identify the causes and fix your hardened brake pedal after a bleed.

Let’s dive right in!

Read more: How to Bleed Brakes without Bleeder Valve?

hard brake pedal after replacing master cylinder

Why is my brake pedal hard after bleeding?

Before we discuss how to fix your stiff brake pedal, what does it mean when the brake pedal is hard to push down?

You may have noticed difficulty pushing down your brake pedal, or, in some cases, the brake becomes stiff or locked.

Over the years, I have discovered that the primary cause of stiff brakes is improper bleeding due to inexperience or bad techniques.

Here are some other causes of the hard brake after bleeding:

Incorrect Bleeding Technique

Incorrect technique due to impatience or inexperience is a common cause of a hard pedal after bleeding.

I remember my first attempt at bleeding by brake; being so impatient, I didn’t allow the air bubbles out of the system. The best way is to follow the right technique on how to bleed your car’s brake.

Damaged Brake Booster

When your vehicle brake booster is damaged or has reached its life span, it can malfunction and cause a hard brake.

The Booster uses a vacuum pressure that assists the driver when the brake is pressed. Without it, the driver will require more effort when braking. Other symptoms of a bad brake booster include hissing sounds, leakage, a higher pedal, and more.

Improper alignment of the Brake push rod

During the bleeding process, I discovered that the Push Rod was tightened so much, leaving insufficient space between the master cylinder and the brake booster.

This is caused mainly by inexperience, and why I stress the importance of correct adjustment and calibration of all components of the car.

Blocked Brake line

It is also possible that your brake line has a particle stuck within it, preventing fluid flow and consequently hardening the brake pedal.

hard brake pedal after replacing booster

What should I do if the brake pedal becomes hard after Bleeding?

When it comes to how to fix a hard brake pedal, solutions will vary depending on what the primary cause was identified.

For instance, after inspection, you may have discovered that your vehicle brake booster is faulty and needs to be replaced or any parts of your brake system.

Following these steps, you should be able to fix the hard pedal after bleeding.

Ensure Bleeding is done correctly:

Typically, bleeding involves forcing brake fluid from the master cylinder to the caliper of the disc brake until the air bubble is removed from the system. To do this, the bleed screw is loosened to the highest point, and the fluid is allowed to escape till there are no air bubbles.

Then the screw is tightened, and the fluid is refilled. The process is then repeated for each wheel of the car.

Inspect the Brake Booster:

Brake pad hard and no brake or locked brake can be traced to a failing brake booster. A vacuum leak or hissing sounds also accompany a failed booster.

There is also a possibility that the Brake Booster check valve is damaged. It is responsible for preventing air from entering the brake system.

Follow this step to inspect your brake booster:

  • Make sure your engine is off
  • Pump the brake fully until the brake becomes hard
  • Start your engine. The brake pedal should sink slightly (Usually by an inch). If it does, it means the booster is working fine, and you have a brake assist, else you should get it replaced.
  • Check if the brake booster is giving a vacuum.

Inspect the master cylinder.

The Master cylinder of your car is responsible for generating a hydraulic pressure that is responsible for activating the brake.

A damaged master cylinder may lead to pressure loss or improper distribution in the car. Because of the lack of force generated by the caliper, you may notice that the brakes are hardened and difficult to press down.

Pay close attention to the master cylinder during your fix.

Read more: How to test your master cylinder.

Consult a professional

If you have bled the brakes successfully and inspected the components without discovering anything, seek professional help.

There is no shame in asking for help; even as a mechanic for many years, I still ask my colleagues for help.

A professional mechanic has the knowledge and skills to diagnose complex automotive problems.

What should I consider to avoid these problems after brake bleeding?

There are important factors to consider to avoid complications after bleeding your brake system are:

  • Using the correct brake fluid: many novices apply any brake fluid to their brake system, which is responsible for many complications. I recommend using only manufacturer-recommended fluid for your car.
  • Follow the right bleeding procedure: You can consult your vehicle manual on the best bleed brake fluid from the system.
  • Maintain fluid level: After bleeding, you are expected to refill the fluid in the brake system. Low fluid can damage the entire braking system and cause brake failure.
  • Check for leaks: leaks in the brake line, manifold, hose, and other components. Leaks can cause a potential loss of power due to low fluid.
  • Check the brake pedal: Test the brake pedal for responsiveness and functionality.

Final words

Maintaining your brake system is a crucial skill for every car owner. Keeping a sound brake system allows you to drive safely and confidently. 

If you are experiencing hardened brakes, we recommend following the instructions and tips in this article. Don’t panic if you haven’t been able to fix it yet. Instead, seek professional help from a mechanic.

Akindayini Temiloluwa

I am passionate about everything automotive. Right from when I got my first toy car as a kid, I developed an interest in the inner workings of vehicles. As I grew up, my love for mechanical stuff became more substantial enough for me to pursue a career in it. My goal as an automotive content writer is to simplify the most challenging concepts for my readers, help them self-diagnose what may be wrong with their vehicles and offer real value for their time.

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