New Brake Pads Don’t Fit in Caliper (Causes)

When you buy new brake pads, there is always a chance that they will not fit into caliper. When you discover that new brake pads don’t fit in caliper, there are corrective steps you can take. But before delving into that area, you need to know what causes this issue. Ideally, the new brake pad should not fit too tightly or loose in the caliper. You need to make sure that all possible sources of this problem are eliminated from the start.

new brake pads don't fit in caliper

Reasons of new brake pads don’t fit in caliper

Many factors can cause the brake pads to fail to fit in the caliper. Before you even look at why brake pads don’t fit in caliper, start with your supplier of the brake pads. Some spare-part manufacturers miss tolerances because of mass production. Other possible factors like corrosion in caliper bracket, wrong sized brake pads or wrong pad orientation can cause this issue, as outlined below:

Corroded Caliper Bracket:

This is a very common issue for vehicles that have been on the road for a long time. The slides where the pads should move develop a layer of corrosion that prevents the pad from being fitted. These usually need grinding brakes or removing the corrosion with an antirust or penetrant liquid.

Extended caliper piston rod:

You may find that the piston rod that pushes the brake pads has extended without retracting to its initial position. This requires compressing the caliper.

Brake pads too thick:

 In this case, the caliper could be of the right dimensions and size. But you got a new brake pad which is too thick to fit in. There is a high possibility you stuck to the correct brand, but you mismatched the vehicle’s year of manufacture. There is also a chance that you bought the wrong brand or some poor-quality pad.

Pads too thin for the caliper:

There are cases where you will find that the brake pads are too thin to fit well in the caliper. If you leave them installed there, they can easily come out and fall off.

Brake pads fitted the wrong way:

The shape of the brake pad guides you into fitting it the right way. It will show you the correct orientation for its type. But a new mechanic may forget to ask a simple question, which way do brake pad clips go? In the end, they force the clips the wrong way and it fails to fit.

Worn-out caliper:

You may also encounter cases where a caliper is worn out and can’t accommodate the new brake securely. This is common with calipers are used in less rusty environments requiring heavy braking. This could also be coupled with using materials that wear out the caliper brackets.

Do all Pads Fit All Calipers?

Generally, we expect all vehicle manufacturers to comply with the Society of Automotive Engineers standards, SAE. But even when manufacturers do this, all pads can’t fit in any caliper. This is because the sizes of the wheels for different vehicles also differ. Eventually, even the rotors or brake discs come in different sizes. A bigger wheel will come with a bigger disc that will call for a bigger brake pad and vice versa.

The location of the brake pad also determines its size. Therefore, brake pads for the front wheels differ in size from those of the rear wheels. That is why they cannot be universal because they are applied differently.

The sizes of the brake pads also differ depending on the year of manufacture of the vehicle. Different brands also call for different sizes of pads and calipers. This also means that some manufacturers have their shapes of brake pads. 

How tight should brake pads fit in the caliper?

Brake pads should not fit so tight that movement is restricted. If you do it this way, the piston rod will not easily retract when put to use. At the same time, the brake pad should not be too slack. This can cause it to wiggle out of position or misalign itself while in use. As a rule of thumb, when installed, the brake pad should slide in smoothly with a small push.

If you are forcing it in or feel the need to hammer it into position, it is too tight. It is too slack if you also fit it in so loosely that it fails to follow the slideways. Also, secure the brake pad clips. Ensure that they are installed correctly. You need to be familiar with f250 brake pad clips installation procedure to do it right.

How do you compress brake calipers with new pads?

During the installation of new brake pads, the caliper may also need to be compressed so that the new brake pads fit in well. The focus of the compression is to retract the expended piston. One of the methods used involves the use of a compressor tool which is designed for this task. You can carry out this installation by following the steps below:

Step 1:

Select the correct tool compressor tool or air wrench for the task. Make sure it has all the adapters and accessories for the task.

Step 2:

Fit the tool in the caliper with the securing plate directly above the extended caliper piston rod.

Step 3:

Fit the adapter on the piston rod and tighten the nut to make sure the tool is secured in the caliper.

Step 4:

Tighten the tool by rotating it clockwise so that it allows the adapter to push the piston outward. Continue with this process until the piston flushes with the bracket of the caliper.

Step 5:

After you are satisfied with the compression so far, you can loosen the nut and remove the tool.

Always check on the brake fluid and ensure it is not leaking out. You should also be sure that the brakes are not applied. After everything is done, look out for lubrication points that need grease. In this case, you can grease the sliding end of the brake pad and its bolts. When you use the brake pad grease autozone recommends, you can be sure of good results.

Brake pads don’t fit You Tube

Can you compress brake caliper without a tool?

When compressing a brake caliper, you may not have the special tool for the task. In this case, you can still make sure of what is available. You should have in mind that you need to force the piston to compress the piston into the right position. Without a tool, it is still possible to compress the brake caliper. Just as you mastered how to install duralast brake pad clips without the preferred tools, this can also be done.

The only factor you need to manage is that, the task will take longer in the absence of a tool. You also need extra skills to select and use the right alternative tools effectively. The most obvious is a big flat screwdriver wedged against the rotor.


When you discover that new brake pads don’t fit in caliper, you have some work to do. The task is possible but requires skill with the right tools. Beforehand, you should have ensured that you are using quality brake pads of the right brand for the design of your vehicle. In some cases, you may also need to look out for brake pad orientation at the beginning. You might need to check to install it the right way. Paramount to all this is the effective use of the right tools to accomplish the task.


Mr. Shafiqule Islam is a graduated Mechanical Engineer and has more than 15 years experience of repairing and maintenance of different brand vehicles like Toyota, Mitsubishi, Ford, Mercedes, BMW etc. He is also giving training to Mechanics. He has started writing to share his practical knowledge to Vehicle Owners, Drivers and Mechanics to keep their cars at best fit.

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