Raybestos Best Brake Job: Checking Lateral Runout

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Doing the best brake job possible takes time and effort. You can't take shortcuts and you must follow the proper procedures. In this series, The Best in Brakes will teach you how to perform the best disc brake job. Our technical service experts will teach you how to inspect your brakes and the steps you must take to do a quality brake job. In part five of this series, we talk properly checking lateral runout.
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Measuring lateral runout is an essential component of a quality brake job. If you don't take the time to measure lateral runout, you are at a higher risk of a comeback.
Checking Lateral Runout Steps:
1.) Wash rotor with soap and warm water to clean the rotor of any debris.
2.) Install the rotor onto the vehicle.
3.) Slide conical washers over the studs of the wheel.
4.) Tighten down the lug nuts. It does not have to be to specifications. But you must tighten down the lug nuts evenly. We use the yellow torque stick (65 ft-lb).
5.) Install the dial indicator.
6.) Turn the rotor and measure the lateral runout. Check the rotor's runout against the specifications in your spec guide. Most modern vehicles have a lateral runout of .002.
7.) If the runout is too high, remove the lug nuts and conical washers and turn the rotor 180 degrees. Then, repeat steps 2-6.
Why Check Lateral Runout?
Even if you are installing a brand new rotor, it is critical that you check lateral runout. An issue with the hub assembly could cause excessive runout, even with a perfect rotor.
If you let a vehicle leave the shop with excessive lateral runout, there will be no problems at first. However, with today's tight tolerances, problems will soon occur.
Excessive lateral runout causes the rotor to wobble as it turns. An excessive runout of a few thousandths causes the rotor to make contact with the pads during every revolution. This contact occurs even when the brakes aren't applied. Over time, as the pads make contact with the same spot on the rotor, it results in a thickness variation. The thickness variation on the rotor's surface leads to pedal pulsation when braking.

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Where do you get those kind of washers?