Brake Pad Thickness. Everything you need to know
Brake pads sit between the brake shoe and the brake drum, and they are crucial to the brake system of a vehicle. Brake thickness also plays an essential role in engine’s proper operation, and also for road safety. The normal lifespan of brake pads is 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. Two of the most common reasons to measure a disc pad are pad identification and pad wear checking.
How to choose the correct brake pads for your vehicle
Nowadays it’s hard to find the correct brake pads for the vehicle, especially when some cars can be fitted with several different brake options.
The best and easiest way to ensure you get the correct pads is to check the shape and size of the pad already fitted. Sometimes a visual inspection or back-to-back comparison of the pads is enough to identify the difference, other times when the pad shape is the same, a couple of simple measurements will verify the part. Measuring can also help you to determine the worn out brake pads through their thickness. The following step-by-step guide can help you to select the correct brake pads for your car and to identify the damaged brake pad.
1. Locate the rotor on the front brakes. It is the round metal part that your rubber wheel fits over. Many vehicles will have drum brakes on the rear wheels instead of rotors, which have brake shoes rather than brake pads.
2. Find the caliper. The large metal piece clamped to the side of the rotor is called the brake caliper. Inside of the caliper, you can see a rubber lining which are the brake pads.
3. Push a straw in between the brake caliper and rotor. Continue pushing the straw until the straw hits the brake disc and stops.
4. For an accurate reading, use a vernier caliper. It is a measuring tool that's able to measure in small spaces where a ruler can't reach. Stick the end of the vernier caliper through the hole and read the top of the tool to get a measurement for your brake pads.
5. Measure it. Use a marker to make a line where the straw and brake pad meet. Use a ruler or tape measure to measure the space between the end of the straw and your line. This will give you an approximation for how thick your brake pads are.
6. Subtract 5 millimeters (0.20 in) from the number. The brake pad backing plate is about 5 millimeters (0.20 in) thick, that’s why you must subtract it from your number to get the exact width of the brake pads. Your brake pads should be at least 1⁄3 inch (8.5 mm) thick after you subtract 5 millimeters (0.20 in)
7. Replace your brake pads if they are under 1⁄4 inch (6.4 mm) thick. A new brake pad is usually around 1⁄2 inch (13 mm) thick. Brake pads that are 1⁄8 inch (3.2 mm) thick should be immediately replaced and aren't safe to drive on.
Measuring Your Brake Pads by Taking off the Wheel
1. Jack your car up on the side that you want to examine.
2. Remove your wheel loosening and removing the bolts by turning them counterclockwise with a lug or torque wrench. After pull it off the rotor. Now you will see the brake rotor and caliper.
3. Locate the brake pads. If you look into the hole in the caliper, you can see both internal and external brake pads. Measure both sides of the brake pads.
4. Use a compass to measure the brake pads. Use a compass to measure the width of each side of the brake pads. Position one prong of the compass on the left side of the pad and position the other prong on the right side of the pad. Measure the space in between the prongs on the compass to get a measurement for your brake pads.
5. Replace them if brake pads thickness is under 1⁄4 inch (6.4 mm) thick. If your brake pads are 1⁄4 inch (6.4 mm) thick, it means that they need to be replaced soon. If they are 1⁄8 inch (3.2 mm) thick or less, they need to be replaced immediately.
New Brake Pad Thickness
The standard thickness of a new brake pad is usually 12 mm, and it will last more or less 35,000 miles.
If you are using the brake often while driving, the brake pads will not last long.
Minimum Brake Pad Thickness
The brake pad thickness has to be at least 1⁄4 inch (6.4 mm) or more for its proper functioning. Remember, if the thickness is between 6.4 to 3.2 mm it will save the brake system from severe damages.
The following information is also vital for selecting the correct brake pad.
Fitting Position: This is the position of the brake pad; it will either be for the front or rear axle.
Brake System: These are the manufacturers of the brake pads if more than one manufacturer is shown when you have a car selected you will need to check your brakes for the brake system of the pad fitted.
Wear Warning Contact: A Brake wear indicator, also known as a wear warning contact, is used to warn the driver of the vehicle that the brake pad requires replacement. If your brake pads have wear warning contact system, then you must select a brake pad that has this function.
From/Up To Construction Year: Some brake pads only fit a vehicle from or up until a specific time.
If you are still in doubt what are the correct brake pads for your vehicle or if you want to know if they are worn out or not, then better to contact your trusted mechanic or to check the vehicle owner’s manual for more info.