HotRodNeil

I just install RotorPro slotted cross drilled rotors on all fours, and then measured the runout:

rear passenger .07 lateral runout
rear drive .10 lateral runout
I'm getting some thumping when stopping. The old rotors were very warped.
Specs call for no more than .02 so they're way off.

I checked them after driving 50 miles. Did not check the front yet. Is it normal to have to turn brand new rotors? Both of my trusted repairmen said yes, it is common. I have heard good success stories on these rotors, so I choose them carefully.

I also had one hell of a time getting the runout gauge stable to measure it. I had to clamp the gauge to the caliper bracket, because of some play in the rear axle to and fro. Is a runout gauge really that accurate with all the problems of stuff moving? We're only talking about a few thousands, which is not much.

Thanks

BriancWS6

iTrader: (18)

That is pathetic for a set of rotors. I am a machinist and I can tell you that .070-.100 is pure **** work. I honestly don't see how you could turn some that poorly. I could get that close with an angle grinder!!! Take those off and send them back. You shouldn't have installed them at all. In fact the .020 runout is actually shitty as well for new. It isn't hard to manufacture a rotor correctly.

HotRodNeil

Brian:
Thanks. Is the runout gauge a pain to use on the wheel? It looks similar to this, but with a pair of vice grips:
http://eastwoodco.com/shopping/produ...emType=PRODUCT

If you're not careful, the gauge bounces all over the place!! Could I use a laser pointer to do a rough check (shoot it sideways to skim the rotor)?
Neil

BriancWS6

iTrader: (18)

A dial indicator isn't hard to use at all IMHO, but I have some experience with them So your saying that instead of a mag base it has a clamp to hold the base? Well one thing that will make the indicator needle move around is the slots in the rotors. For a surface like this I would just get a micrometer or set of dial calipers and measure at 12:00, and in small increments all the way around and you will find how much it runs out when you find the thickest and thinnest points. But by you already knowing that it is at least .070 they are scrap IMO. You could have them turned and trued up, but they should have been true when they came off the production liine. By truing them yourself or at a shop you are already decreasing the life of them. Good luck!

Foxxtron

iTrader: (1)

Time for some brand new duralast or brembo blanks. From my experience it isn't unusual for some rotors to need some slight resurfacing before installation, however it can be rare. BriancWS6 is right, those rotors are definitely no good.

HotRodNeil

Brian:

I didn't even think about using a micrometer! Good idea! Than I won't have to screw around with this piece of crap runout gauge. That will solve the problem.

Also, to the other person, I measured the rotors on the 1/8 inch strip just above the slots, so the needle wouldn't jump up and down. Thanks.

pimpmaro

I've heard that if rotors are stored vertically instead of flat, that can actually cause them to warp under their own weight. They might have been machined just fine but stored improperly.

DONAIMIAN

iTrader: (18)

damn, thoes rotors were so eager to get warrped they didnt even wait to get on the car.

pimpmaro

Talk about a warped sense of humor...

BriancWS6

iTrader: (18)

Hmm, so that means that they will literally warp sitting still while on the car That's not gonna happen fellas.

Foxxtron

iTrader: (1)

I've heard that one, however the problem lies with the manufacturing quality control. If there is poor quality control, then the defective item ends up wherever the item is distributed.

The rotors are usually supposed have a final surface job before they are installed. Regardless of whether it's done by vendor or mechanic, this is necessary to make sure the rotor is even on both sides. Preliminary thickness needs to be insured before the rotor is even supposed to move on to any other steps. If the rotor thickness isn't within spec upon leaving the cast, then it should be scrapped for remanufacturing.

jxaxsxoxn

iTrader: (2)

I guess you thoroughly cleaned your hubs and then bolted the rotors on with all five lug nuts torqued to spec?
Did you check the runout of the hub only?

HotRodNeil

Here's an update. I spoke to the dealer and will take the rotors back and check them to see what happened. I'm going to micrometer all four rotors before I ship them back. Then I'm getting Eradispeed and will clean and check the hubs and do it by the book. lateral runout on hubs is rare, but I'm going to check anyway. Yes, they will be very clean before I install the new ones.

We took the car in for inspection, and when we got the car back we checked the torque, some of the wheels were torqued to about 60 ft-lbs, and others 80 ft-lbs. I told my son to check the torque at the dealer, but he forgot and drove them like that for 2 days.

I've had 5 Camaros since 1995 and had many sets of rotors go bad, most replaced by the dealer. Hopefull the Eradispeeds with their lifetime warranty will solve the problem.

pimpmaro

My understanding is that it's when they're stored on edge, not when suspended by the hub.