What Causes Brake Fluid Leaking From Caliper Bolt?(Fix Now)

One of your vehicle’s most important systems is its braking system. So, when the braking fluid starts to leak from the caliper bolt, it can lead to many problems, and you should fix it asap. 

The core reason that causes brake fluid leak from caliper bolts is due to components like brake pads and rotors producing excessive friction. There can be other minor reasons too which can lead to leaking brake fluid like worn out and damaged seals.  

So, if you are wondering why the brake fluid is leaking from the caliper bolt of your car, you are in the correct place. Today we will discuss all the reasons causing this and how to fix it.

What is a Caliper Bolt? 

Before we discuss why brake fluid leaks from the caliper bolt, we will need to understand what a caliper bolt is. The disc brake system, the kind seen in most automobiles’ front brakes, includes calipers. 

The brake pads and pistons of your automobile are kept within the brake caliper. Its duty is to make friction with the braking rotors in order to slow the wheels of the vehicle.

Its main job is to provide force to the brake pads against the rotor to stop the vehicle. Caliper bolts secure the bracket-shaped part of the brake caliper to the spindles or steering knuckle.

Read Also: Can You Use Brake Cleaner As Starter Fluid? (Explained)

What Causes Brake Fluid Leak From the Caliper Bolt? 

Leaking brake fluid can lead to many different safety issues and to fix these issues it is essential to find the root of the problem. 

What Causes Brake Fluid Leaking From Caliper Bolt?(Fix Now)

Worn Out Seals

One of the most common reasons for brake fluid leaking from the caliper bolt is worn-out seals. A single piston connects and controls the drum brake rotor, master cylinder, and disc brake caliper. 

Brake fluid helps to move this piston and it features seals that aid in fluid containment, and normal wear and use can harm these seals. Damaged seals can easily lead to a leak. 

These seals deteriorate with time and when the piston seals get damaged, you will need to replace them with new ones. It is advised to replace the seals with new ones every five years; the replacement costs might range from $50 to $150.

Read Also: Brake Fluid Leaking Under Middle of Car | What to Check?

Problematic Master Cylinder

The piston receives fluid from the master cylinder and whenever the brake pedal is pushed, the two metal plates where the piston is placed are pushed together. 

As these plates are pushed together, friction is created between the brake pads and rotor which causes the automobile to come to a stop. Hence due to this a great deal of heat falls on the master cylinder since it is made of plastic.

So over time the master cylinder starts to become weak and can crack down which would let brake fluid leak.Unfortunately, you cannot fix a problematic master cylinder, and you will need to replace it.

The replacement is pretty easy, and you can do it easily by yourself. A new master cylinder is priced between $140-$300 and labor costs between $170-$330. 

Damaged Rotors

Using worn brake pads for an extended period of time might harm the rotor. When you use the brakes, metal-on-metal interaction results from the metal in the brake pad wearing down and being exposed. 

The rotor will acquire deep gouges as a result of this damaging interaction between the pad and the rotor. Hence, the rotors will eventually deform if they experience excess wear.  

Whether the rotor can be fixed or has to be replaced depends on the extent of the damage. You may resurface the rotors sometimes. Rotors that have been resurfaced have had some of their metal removed, leaving a smooth, uniform surface. 

If it is beyond repair, though, you will need to replace it. Resurfacing a rotor can cost $100 to $400, and replacing the entire rotor can cost $150 to $250 for each axle.

Worn Out Brake Pads

Another common reason for leaking brake fluid from the caliper bolt is worn out brake pads. The heat produced by the friction between the caliper and the rotor must be dispersed, and brake pads are crucial for this. 

Over time, they may become worn out and lose their ability to distribute heat effectively. Therefore, when they are fully ruined, it can harm the rotor and result in issues like braking fluid leaks.

Breaking pads are something that must be changed regularly, and they can cost between $115-$300 per axle. This cost includes replacement costs along with labor costs.

Should I Drive with Leaking Brake Fluid From the Caliper Bolt?

Although it is theoretically possible to drive with leaking brake fluid, it is not advised. Any brake caliper leaks will affect the braking system’s ability to shut under pressure. This will not only cause a waste of brake fluid but also severely reduce how well the car can stop. 

Thus, this can result in unwanted accidents in the center of the road. So, you shouldn’t just take a chance with your brakes. As a result if you wish to have the automobile fixed, you may tow it there or hire a skilled mechanic to come to your house rather than driving it. 

Read Also: How to Deal with Brake Fluid Light On But Fluid Is Full?


This section is all about the faqs related to our today’s discussion about leaking brake fluid from the caliper bolt. Keep on reading to know more.

Can Brake Fluid Leak From a Brake Caliper?

Your brake caliper may leak, and there are a variety of causes for this to happen. Leaking brake fluid is risky and it can damage the hydraulic pressure in your braking system. So, if your caliper leaks, you need to fix it immediately.

Why is my Bleeder Screw Leaking?

The caliper connections with the bleeder screws are all metal-to-metal and serve as caliper vent valves. They will leak if they are too stiff, and if they are too loose, they will also leak. Therefore, you must maintain the screw’s perfect tightness.

What are the symptoms of a bad brake caliper?

A bad brake caliper will show many symptoms, including brake fluid leaks, decreased stopping power, and leaking brake fluid. Other signs include strange noises while braking and a constant sense of brake engagement when driving.

What is the ideal tightness for a bleeder valve?

Braking fluid might leak if the bleeder valve is excessively tight. Therefore, avoid using a ratchet to twist your bleeder screw. For bleeder screws, torque values around 6 lbs-ft and 10 lbs-ft are suggested.


Braking fluid leaking from the caliper bolt is a very serious issue, and you must take it seriously. Driving your car with this problem can lead to even more problems like damaging other components of your car. Additionally,  leaking brake fluid can even lead to serious life taking accidents.

So, you should fix the issue as soon as possible, and for that it is important to find the root of the problem. Additionally, fixing the brake system caliper is not that easy, so the best option is to visit a professional mechanic to do the fix for you.

However, if you wish to repair the brake system caliper by yourself, ensure that you have the proper tools for the work.

Similar Posts