Machine Rotors? Say What?!
Thread Starter
Instructor
Joined: Apr 2011
Posts: 212
Likes: 1
From: Dallas TX
Machine Rotors? Say What?!
I just ordered a set of Carbotech Bobcat 1521 pads for my 2011 Grand Sport. Then I read the following on Carbotech's FAQ:
If you have had another manufacturers brake pads on those same rotors; then you will ABSOLUTELY have to replace or resurface (turn) those rotors before installing the Carbotech brake pads.
Say what?
My car has ~1,000 miles on it. Just how important is it to remachine the almost-new rotors? Will light hand sanding suffice?
If Carbotech's admonition is important, is this true of all pads, or just Carbotech's?
If you have had another manufacturers brake pads on those same rotors; then you will ABSOLUTELY have to replace or resurface (turn) those rotors before installing the Carbotech brake pads.
Say what?
My car has ~1,000 miles on it. Just how important is it to remachine the almost-new rotors? Will light hand sanding suffice?If Carbotech's admonition is important, is this true of all pads, or just Carbotech's?
Tech Contributor
Joined: Oct 2008
Posts: 1,378
Likes: 11
From: St Louis MO
There's a Carbotech guy here who probably know better but unless you plan to track the car, I'd try running them normally on the street for 500 mi before performing the bedding process.
The bedding process embeds a thin layer of the pad on the rotor so the rotor needs to be clean metal before doing this. If you do it right, you can actually see it on the rotor.
Light street driving hopefully will remove any deposits from the previous OEM metallic pad, especially if you haven't driven hard the first 1,000 mi.
I find when not spending time on the track, I have to repeat the bedding process every 500 mi to prevent squealing.
I've also seen using a flex hone rotor burnish tool recommended over turning the rotors but it should really be done with the rotor off the car in a controlled manner.
The bedding process embeds a thin layer of the pad on the rotor so the rotor needs to be clean metal before doing this. If you do it right, you can actually see it on the rotor.
Light street driving hopefully will remove any deposits from the previous OEM metallic pad, especially if you haven't driven hard the first 1,000 mi.
I find when not spending time on the track, I have to repeat the bedding process every 500 mi to prevent squealing.
I've also seen using a flex hone rotor burnish tool recommended over turning the rotors but it should really be done with the rotor off the car in a controlled manner.
Last edited by StKnoWhere; May 20, 2011 at 07:31 PM.
Team Owner
Joined: Sep 2005
Posts: 20,352
Likes: 568
From: Ventura County, Calif
I have a vague memory of Adam mentioning that before but I'm not sure of the context. Here's Adam's phone, you should probably just call him and talk about it. 
http://forums.corvetteforum.com/1574295418-post3.html
http://forums.corvetteforum.com/1574295418-post3.html
Pro
Joined: Sep 2005
Posts: 695
Likes: 19
The instructions for the Hawk's I just put on said 130 grit, so yeah just scuff them with some sand paper and your fine.
Honestly, if the pads aren't abrasive enough to remove the material from the previous pad then you went in the wrong direction of stopping power.
Honestly, if the pads aren't abrasive enough to remove the material from the previous pad then you went in the wrong direction of stopping power.
Team Owner
Joined: Jun 2005
Posts: 46,295
Likes: 2,596
From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
I have a vague memory of Adam mentioning that before but I'm not sure of the context. Here's Adam's phone, you should probably just call him and talk about it.
http://forums.corvetteforum.com/1574295418-post3.html
http://forums.corvetteforum.com/1574295418-post3.html
Supporting Vendor
Joined: Oct 2002
Posts: 50,281
Likes: 518
From: Cleveland OH
St. Jude Donor '11,'13
I just ordered a set of Carbotech Bobcat 1521 pads for my 2011 Grand Sport. Then I read the following on Carbotech's FAQ:
If you have had another manufacturers brake pads on those same rotors; then you will ABSOLUTELY have to replace or resurface (turn) those rotors before installing the Carbotech brake pads.
Say what? My car has ~1,000 miles on it. Just how important is it to remachine the almost-new rotors? Will light hand sanding suffice?
If Carbotech's admonition is important, is this true of all pads, or just Carbotech's?
If you have had another manufacturers brake pads on those same rotors; then you will ABSOLUTELY have to replace or resurface (turn) those rotors before installing the Carbotech brake pads.
Say what?
My car has ~1,000 miles on it. Just how important is it to remachine the almost-new rotors? Will light hand sanding suffice?If Carbotech's admonition is important, is this true of all pads, or just Carbotech's?
You will be ok, just clean them up a bit with light hand sanding and bed in the new pads. you will be fine not a big deal.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Racer
Joined: Oct 2009
Posts: 252
Likes: 2
I just ordered a set of Carbotech Bobcat 1521 pads for my 2011 Grand Sport. Then I read the following on Carbotech's FAQ:
If you have had another manufacturers brake pads on those same rotors; then you will ABSOLUTELY have to replace or resurface (turn) those rotors before installing the Carbotech brake pads.
Say what? My car has ~1,000 miles on it. Just how important is it to remachine the almost-new rotors? Will light hand sanding suffice?
If Carbotech's admonition is important, is this true of all pads, or just Carbotech's?
If you have had another manufacturers brake pads on those same rotors; then you will ABSOLUTELY have to replace or resurface (turn) those rotors before installing the Carbotech brake pads.
Say what?
My car has ~1,000 miles on it. Just how important is it to remachine the almost-new rotors? Will light hand sanding suffice?If Carbotech's admonition is important, is this true of all pads, or just Carbotech's?
Chris
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
While there are concerns that sanding will removal brake rotor iron, you would have to sand for hours to remove any measurable material. I've sanded rotors with a orbital sander and 80 grit with positive results to eliminate brake noises.
Even if you have the rotors turned, which is not necessary, sand the rotors.
After sanding, make sure you wash the rotors off with soap and water followed by commercial brake clean spray. This will remove any oils from handling the rotors and sand paper grit.
Racer
Joined: Oct 2009
Posts: 252
Likes: 2
Chris
Safety Car
Joined: Jan 2004
Posts: 4,974
Likes: 14
From: Pinellas Park Fl
St. Jude Donor '08-'09 & '12, '14
Since it only takes .002-.003" to eff up a rotor, and it only takes moments with 80 grit to do (which I've had happen), using sandpaper is an unnecessarily risky technique. Anyone using sandpaper on racing rotors would be instantly fired from a pit crew. Even for street cars, a Flex-Hone or Scotch-Brite are the way to go.
Chris
Chris
I have used sandpaper on rotors for over 20 years without a problem. I have also used 80 grit Roloc discs on a rotor to give it a non directional finish without a problem.
Instructor
Joined: Feb 2011
Posts: 102
Likes: 4
From: Brownsburg IN
The difference would be if your using the disc in an 800rpm drill motor or a 12,000 rpm high speed. An 80 grit disk in a high speed will take off .002-.003 in seconds.
Racer
Joined: Oct 2009
Posts: 252
Likes: 2
Chris
