How to Gauge the Proper Brake Lining Thickness

  • 2-3 hours
  • Intermediate
  • 10-20
What You'll Need
Brake lining gauge
Jack stands
Friend or brake depressor

Determining the correct brake lining thickness in your car is an essential part of road safety. The lining has to be a certain thickness, otherwise the pads will not work and you will be unable to stop the vehicle in time. Most car owners allow their garages to measure the brake lining during yearly services, but this can result in unnecessary replacements and a lot of expense. In order to protect yourself from this, you need to know how to measure the proper brake lining thickness and how to do it quickly and easily in your own home.

Step 1 - Prepare the Car

In order to test the brake lining, you will need to have access to the brake pads. The best way to do this is to invest in a large car lift device which carries the car to eye level. If you cannot afford this, and most people can't, then you should simply prop your front wheels up on some car jacks and support with jack stands. Remember to block the back wheels to prevent them from sliding on your driveway while you are using the jacks. Once you are able to see the brake pads, make sure that they are completely clean. Use the tip of a flat head screwdriver to scrape away any mud that you find.

Step 2 - Take the First Measurement

You will need to take two measurements of your brake lining. The first measurement should be performed while the brakes are not being used. Take the tip of the gauge and place it between the top of the shoe or pad and the drum on which it rests. You should be able to fix this tightly into place.

Step 3 - Take the Second Measurement

With the help of a friend, or with some way of pressing down upon the brake, take the second measurement with the brakes being used. Slide the gauge into the same area as before and measure again. You should take special note that the gauge fits completely around the lip of the brake drum and sits securely. Remove the gauge.

Step 4 - Interpret Your Results

You should have two sets of results from your gauge experiment, the first without brakes, and the second with them applied. The gauge should have fitted perfectly around the drum on both occasions. If the gauge could not fit between the drum and brake pad or shoe on the second test, then the lining has been worn down to below minimum thickness and has to be replaced. If you fitted the gauge between the drum and pads on each occasion, then you have not worn the lining down yet and can leave the brake lining alone.

Step 5 - Finishing

Once you have finished the test on one side, repeat on the other, as the lining can wear away at different rates. When you have finished, take your car down from the jack, and remove the blocks from behind the back wheels.