What is the max runout on rear disc brake rotors? I checked mine and got .002 on the passengers side and .024 on the drivers side. Can they be turned to get that much runout out or maybe I should get a new rotor.
Thanks , Gene

 

nobody have any input on this subject? if you have an old Corvette you must have had to deal with problems like this before .

 

I have to look in my service manual but I believe 0.005" was the limit. If the rear rotors have never been removed, then there shouldn't be that much run out. That's because the rotors were turned at the factory on the spindle. So if they have been removed and not indexed properly there could be more run out.

 

Rotors have been taken off , spindals and bearings have been serviced a while back. I an going to try clocking the left rear rotor in a different location and see what readings I get.

 

Good idea. Look for a center punch mark on the rotor near one of the holes and a matching center punch mark on the spindle flange near the lug bolt or even on the end of the lug bolt.

I checked my service manual and the minimum rotor thickness is 1.230 inches. And also my memory was pretty good because the maximum lateral run-out was 0.005 in.

FWIW, I've put a lot of miles on cars with disc brakes and while I have replace pads, I have never had to replace a rotor. And I've never had a rotor machined.

 

I checked the runout on the spindal flange and got just under .002 then checked runout in five locations runout is .022, .023, .020, .018, and .015 still to much. I saw on youtube where a guy shimmed between the spindal and rotor. Don't know if I can turn the rotor enough to fix it.

 

Just remember that if you get it turned that it has to be w/ the rotor firmly attached to the spindle. I'd try shimming it first. There are circular tapered shims available in the Corvette aftermarket. I'd start w/ Vette Brakes & Products.

 

I sure don't want to take the spindal out and deal with the bearings again. I think i'll try a new rotor. Maybe shims.

 

Since the original rotor was turned on the spindle before installation, a new rotor may not be any better than what you have now. You shouldn't have to worry with the spindle bearings if you just want to use the tapered shims with your existing rotor.

I would also recommend while you're dealing with this with the rotors off, you invest in the stainless steel parking brake setup.