Brake Pad Thickness: What Is The Minimum Depth?

The correct brake pad thickness is vital for not only the engine’s proper operation but also the road safety. Replacing the pads at the right time will save plenty of your money down the road. But, at what thickness should brake pads be replaced? How to correctly do the brake pad measurements and take necessary action? Let’s get to the bottom of it.

What Are Brake Pads?

Brake pads, which sit between the brake shoe and brake drum, are crucial to the brake system of a vehicle. If these are damaged or don’t have the required thickness, other components of the brake system – rotors, calipers, and discs – will be wearing out. It’s important to figure out the right time to replace the pads to avoid unsafe driving conditions.

minimum brake pad thickness
New and old brake pads. Source: Drone Fest

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Brake Pad Thickness: The Minimum And Recommended Limits

Brake pads are made of steel plates, shims, and friction materials. There are two layers of rubberized coating and thermal insulation coating on the outside. Like all other things, these materials wear out over time. Also, rough driving and poor road conditions play a part in hastening the deterioration.

The normal lifespan of brake pads is anywhere between 30,000 – 35,000 miles. However, it can be even more or less depending on the car’s make and model, driving habit, and road conditions.

New Brake Pad Thickness

So, how thick are brake pads when they are purchased new? Well, the new brake pad depth is approximately 12 mm. This is the standard thickness and it will last more or less 35,000 miles.

If you are an aggressive driver that uses the brake often, they will not last long. Also, they get a shorter lifespan than usual when you have to engage the brake frequently due to heavy commuter traffic.

Minimum Brake Pad Thickness

Mechanics suggest replacing brake pads because continuous engagements make their friction material become thin. When the material rubs away completely, the next stage is the failure of the brake.

The brake pad thickness has to be at least 6.4 mm or more for its proper functioning. You can get away with thinner pads sometimes. But, quick replacement when the thickness is between 6.4 to 3.2 mm will save the brake system from severe damage.

The Symptoms Of Thin Brake Pads

A physical inspection is enough to check whether the pads are within the recommended thickness. You will need just a flashlight, inspection mirror, and measuring gauge to do it.

brake pad measurements
You can measure the thickness with simple instruments. Source: eBay

Some warning signs not to ignore are:

  • Metallic grinding or growling sound, which comes when brake discs and calipers rub against each other. It means that the pads are completely worn out.
  • Screeching, squealing, or whining noises when you engage the brakes. If the sound does not go away after a couple of times, you have to check the brake pads.
  • Some cars have an indicator light on the dash to give a thin-pad warning.