What Size Allen Wrench For Brake Calipers?

Looking to replace your brake calipers? You would need to know what size allen wrench for brake calipers is needed. Let us understand the correct size and other details about brake calipers

Brake Callipers are an essential part of the brake system of your car. If you need to replace it or maybe check it, you would need an Allen wrench. 

Wherever there is a wrench, there is always a lot of confusion regarding which size you need to use. Let us peek into the equipment and find out the size required for brake calipers.

Knowing Your Equipment

Before getting into work, you should always have enough knowledge about your tools. Otherwise, you may end up making a mess. 

What Do You Know About Allen Wrench?

An Allen key or wrench is an ‘L’ shaped screwdriver. The wrench is designed for special screws with an internal hexagonal shape.

The dimensions of an Allen wrench constrain the required torque. This type of wrench is widely used in garages and repair shops.

What Do You Know About Brake calipers?

The primary function of the brake calipers is to compress the brake pads against the rotor. The compression, in turn, generates friction which ceases the car’s movement. 


What Size Allen Wrench For Brake Calipers

A brake caliper can be of two types: a floating or a fixed brake caliper. The floating caliper is responsible for compressing the piston, which in turn brings the car to a stop. 


Also read: The right size C Clamp for Brake Calipers


Working With A Brake Calliper

When to Replace A Brake Calliper?

The brake systems are interconnected, and one cannot work correctly without the other. Moreover, a faulty part may damage other components. For example, a broken caliper may drastically reduce the lifespan of the brake pads.

Therefore, it is vital to look for signs that may indicate a broken caliper. Below, I have shared a few of the symptoms: 

  • Your car will tend to pull towards a particular side when you apply brakes. 
  • A clear squealing rather than rattling sound will come from the brakes whenever you are driving.
  • If you notice that your brake pads are not even lasting a few days, you should know that there must be a problem with the calipers.
  • Another typical symptom of a lousy caliper is a constant leakage of the brake fluid. 


You might like to read: Which Brake Caliper Guide Pin Goes On Top


What size Allen key do I need to remove brake calipers?

A standard ⅜’’ should be able to remove brake calipers.

How to Remove Brake Callipers?

Before installing a new brake caliper, we must remove the faulty or the old brake caliper. Removing a brake caliper could be a tedious job. However, you can follow the given steps for that. 

  • First of all, you need to locate the calipers. The exact position of the calipers differs from car to car. Therefore, it is advised to refer to the manual given to the vehicle to find the system. 
  • Before starting to work on the brakes, make sure that the wheels are blocked except the one which you will be working on. Then you should remove the wheels and the brake cables.
  • Then loosen the wheels and raise them using a floor jack. It will help keep any contained below wheels for brake fluid that may come out of the hose. 
  • Now, you should clean the entire brake system, including the hose, bolts, etc. this will prevent contamination issues in a car like rust
  • Then use a line wrench to rotate the securing bolt to prevent any loss of the brake fluid. 
  • If any of these symptoms appear, it is advised to see a mechanic before driving it again. 
  • Next, you will need an Allen wrench of a particular size to loosen the securing fasteners of the caliper. Then carefully pull off the caliper making sure no other part of the brake system is damaged.


What Size Allen Wrench For Brake Calipers


How to Replace Brake Callipers

You should never drive your car without adequately working calipers. A faulty caliper is highly risky. Therefore you should always install a new caliper after removing the older one.

  • The first step is the most crucial step to ensure a longer life span of the new caliper.
  • First, you would need to thoroughly clean the entire brake system, including the brake pads, rotors, mounting clips, securing bolts, etc. 
  • Then you may grease your calipers, as per the manual of the caliper. 
  • The next step is to attach the caliper with the brake pads, which you can do in two ways. You can either take off the brake pads and then connect them to the brake calipers. Or you can attach the caliper with a place without taking it out. Again, you should carefully replace all mounting and securing nuts and bolts along with the caliper. 
  • The caliper packaging is done to provide you a ready-to-install setup. The piston should be fully retracted when you place the caliper inside. 
  • Before placing the calipers, you need to cover all the bolts and clips with silicone lubricant.
  • Here you need to remove the screw and mark it with a Teflon marker. Then install the same crew but in the opposite direction.
  • Then replace the old hose with the new one and secure it using a line wrench. For the last step, you need to let the brake bleed with a pump. 
  • It is then advised to check the working of the newly installed calipers.


You might like to read: Which Brake Pad Goes On The Outside


Answers To Some More Questions About Your Equipment

What size are brake caliper bolts?

Caliper bolts for calipers are of size 18mm.

What tools do I need to replace calipers?

You will need several tools to replace calipers: brake bleeding tool, line wrench, brake fluid, brake plug, container or pan, jack stands, ratchet, Allen wrench, hose, and a few others. 

What torque wrench do I need for brakes?

While working on brakes, it is advised to buy the most powerful one. Because about 50 percent of the work while replacing a part of the brake system requires tightening bolts and nuts. These securing nuts need to be fastened properly to avoid any hazards. A ½’’ is the recommended size. 


What Size Allen Wrench For Brake Calipers


Allen Wrench Size For Brake Callipers.

As there is always considerable confusion around the size of the wrench, it is advisable to invest in sets of wrenches. While that could be expensive, it would prove to be a good investment if you are regularly doing this job. 

The most popular opinion about the Allen wrench size required for brake calipers is ⅜ inch. 

It would be best if you take advice from a car garage, in case a ⅜ inch wrench does not work out for you. Another way is to just measure the size of the nut and accordingly choose the right wrench.


Happy Driving!

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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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