How to Measure Brake Drums and Shoes [Sizes/Dimensions]

Are your brake drums wearing out, and now you are wondering how to repair or replace them? If so, first, you must know the maximum diameter of brake drums to find the perfect replacement.

Driving with burned-out brake drums causes even more damage. The tires will wear out if you keep driving with bad brake drums. Therefore, you shouldn’t delay this task any further, or your expenses will double.

Not only that, but your brakes might fail, and you will end up in an unpleasant situation. To help you prevent any complications, we have chosen the optimal way of measuring brake drums to replace them.

So, don’t delay this task any further; keep reading to get started!

Table of Contents

1. Steps for Measuring Brake Drums Properly

2. FAQs

3. Final Thoughts

Steps for Measuring Brake Drums Properly

You will need a screwdriver, drum puller, and a micrometer to measure the brake drum precisely.

After you have set everything, you have to follow our simple tutorial to measure brake drums correctly.

Remove the bolts or retaining clips from the drums that hold everything together.
Use a drum puller to pull off the drum from the wheel.
Now, search for the maximum diameter in the cast. Most of the time, the diameter is on the rotor on the external surface.

Note: You might be unable to find the interior diameter due to rust. In such situations, you can rely on the specifications chart. For that, you will need the model and manufacturing year of the car, and you will get the measurements.

Put the drum on an even, flat surface with its face down so that its inner side faces upwards.
Inspect the drum’s interior diameter and hub surface to spot any cracks. If there are any cracks, place the extendable arms of the micrometer in them.
After positioning the micrometer, unscrew the lock screw of the arm in line with the micrometer shaft.
If the drum is 10.5 inches, keep one side of the micrometer at 10 inches. The other arm should also be at 10 inches but with the addition of four 0.125-inch marks displayed on the shaft.
For measurement, put the micrometer anvils in the drum and oscillate them back and forth across the drum’s internal diameter.
Keep an eye on the drum’s indicator to spot any anomalies, such as runouts.
Take various readings and compare them and select the highest one. Add it to the drum’s diameter, which is 10.5 inches, and then compare it with the specs.

From this measurement, you will be able to determine whether you can repair the drum brake or you must replace it.

Check Out How to Measure Brake Shoes and Drums:

FAQs

How durable are 3mm front brake pads?

A standard 3mm brake pad will last around 150,000 miles, depending on the aggressiveness and usage of the brakes. Due to this, some people also have an average of 200,000 miles.

What occurs if the brake drums get too hot?

Once your brake drums become extremely hot, they will stop working. The lining will start burning off in the worst-case scenario, which you can sense due to its sharp smell. So, it is better to utilize engine braking by going into lower gears to prevent the brake from heating too much.

Should I change my brake pads to 6mm?

If your brake pads are less than 6mm, you must ask the mechanic to check it in only 1,000 to 2,000 miles which is pretty inconvenient. So, you should replace your brake pad or the rotors.

Are brake pads sold in pairs or in fours?

Yes, brake pads come in pairs mostly, but you can also get four brake pads at once. People mainly sell brake pads in pairs because you should simultaneously replace both pads on wheels. Replacing one brake pad and letting the other exhaust itself will be odd.

Which measurements for brakes are reliable?

You should keep your brake pads’ thickness over 6.4mm for better performance. Mechanics claim that the minimum thickness of the brake pad is 3.2mm. If you own brake pads less than this, you must replace them once they are exhausted.

Final Thoughts

Due to their build, average drum brakes will last you at least 200,000 miles, but they will wear out before time.

It is because the damaged internal parts of the drum brake put more stress on the drum. All of this eventually wears out the drum brakes, and they shrink.

Plus, if the brake drums are in dire condition, it will also harm the brake shoes. So, if you want to avoid any mishaps, replace the brake drums as soon as possible to prevent the brake shoes or tires from wearing out.