[PnCRedJwl2SS]

Originally Posted by Paro

What was the runout on the newly installed rotors?

I didn’t know enough to ask. They replaced my rotors, with a senior mechanic supervising that everything was done to spec. It’s been a few weeks now and all is back to normal. Hope it doesn’t return!

Ah...disregard...I see you were asking someone else in this thread.

[fighting irish]

So I finally got around to measuring runout at the hub and on the rotors. .010” at the hub and .012” at the edge of the rotor on the front driver side. This was on a new rotor after cleaning the hub completely. I’m thinking that the runout at the hub is causing excessive disc thinkness variation resulting in the brake pulsations. What would the fix be? Hub replacement? Shims? I autocross so a shim isn’t sounding like a good solution.

Conversely on the passenger side it was about 0.005” at the edge of the rotor, so I didn’t replace it yet.

[superdave 72]

I had the SAME issue with shaking at tip-in of brakes. Dealer had it for TWO friggen days without doing anything to it and said it was my fault for spraying tire cleaner on tires. Said it soaked the pads and warped the rotors. Got it back this morning, after refusing to pay them $975 dollars to replace all four sets of pads and turn rotors.
Went to a Muscle Car shop that I have used a couple of times for my 3.8 Genesis Coupe and my 2014 Mustang GT. He said it was because of the large buildup of brake dust on the pads and rotor that is causing Pad Hop, because of the buildup. I ordered a set of Powerstop Extreme z26 Carbon Ceramic pads for the front and he will install them on Saturday and turn the rotors. Total coast of pads, turning, and labor, probably UNDER $200. Saved ONLY $800...SHEEEESH! Will let y'all know how it works out.

[ssmofo]

You can warp a rotor if you don't torque the wheels correctly.

[gmcvt]

One possible thought/solution on the hub/rotor runout issue might be using an on car brake lathe. I work for a Honda dealership and for the front wheel drive applications Honda says to cut rotors with an on car brake lathe. It accounts for hub runout.. I had a similar issue as the OP with my Accord and the techs were using the OFF car lathe in our shop. The third time they used the ON car lathe and the problem never came back. There are some lathes that are self powered (meaning that the lathe itself turns the rotor) and others use the engine to spin them. Obviously we would need the former.

[TJay74]

Originally Posted by ssmofo

You can warp a rotor if you don't torque the wheels correctly.

You are not actually "warping" a rotor by not torquing the wheels correctly. You are only distorting the rotor.

Also with how thick the rotors are and the hat is, I highly doubt anyone is distorting a rotor on a newer Camaro from torquing the wheels incorrectly.