How To: Test Brake Rotor Runout

nd4sped

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Ok here is what you need:

Lift or (2) Jack Stands & Hydrolic Jack oh and wheel blocks for the front...
Lug wrench
Dial Caliper Kit
about 30 mins

This is only done on my rear discs since I have AEM slotted rotors up front. But this can be done all the way around with the same steps

Okay first off. Place wheel blocks in front of the front tires. Juck up and support your car with jack stands. Never support your car with a jack only.


Get your Dial caliper ready. BTW this is a very expensive peice of equipment.




Ok take the wheel off.




Place the vice grip here.




Place your Dial here or your desired spot. As long as it will clear the lug wrench.




Attach a lug nut to one of the bolts. Use your lug wrench to turn the rotor.
Turn slowly and watch your dial. For your rotors to be within Spec. The reading can NOT fluctuate more than 4/1000th of a inch ( 0.004 ).

If the needle moves more than 0.004 you need to replace your rotors.

Heat is most common cause of warped rotors. Also improper torqing of the lug nuts can also warp your rotors.




Now to ensure that your expensive wheels & tires dont come off or warping the rotors. Properly torque the lug nuts to OEM Specification.



This was one of the objectives to my Automotive Intro class...Uber easy A!
 


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