13611

Hello all and I hope everyone had a great Thanksgiving. I've heard the term "runout" for many years here and there on the forum and never paid too much attention to it. I think it's time to educate myself about this. I've searched the forum for a detailed description of what this means and how to deal with it but have been unable to find anything really in depth. If anyone could direct me to a thread that covers this topic well I'd appreciate it. I consider myself a very capable DIY'er and well versed in cars. With that said, I've never dealt with rotor runout. I have a 68 that I've been working on over the years. It has rebuilt calipers and replacement rotors sourced from one of our vendors. I just put the front rotors on the front and the rear rotors on the rear and called it good. The car has not seen the road yet. I'd really love to know what runout does to the performance of our Vettes and why it's important to check it. Furthermore, how do I check for it, fix it and what are acceptable tolerances? Thanks in advance, Jason

69FASTFUN

I would look at the utube videos like this one

http://www.bing.com/videos/search?q=...=0&FORM=VDQVAP

doorgunner

FWIW.....................If the rotor does not "sit" flat on the hub, rotor run-out exists.

If the thickness of the rotor varies where the pads press against it, the variation can also be called "run-out".

'75

Here's an old thread with some info. There are now tapered shims available to correct it. Because GM mated the rotor and hub or rear spindle together and then machined the rotor, they are not necessarily true once separated. Sometimes a new rotor bolted to the old hub will wobble, or if the originals are separated and not put back the same.
https://www.corvetteforum.com/forums...post1567002304

13611

Thanks for the help gentlemen.

doorgunner

FWIW.......be sure to re-set the bearing play after the rotor is "trued".