New OEM Brake Rotor Problem?
Thread Starter
Drifting
Joined: Sep 2001
Posts: 1,875
Likes: 27
From: Long Beach NY
New OEM Brake Rotor Problem?
I recently purchased a set of OEM Brake Rotors (GM made in Canada). I noticed what I think might be a problem with one rear rotor. I hope some experts on the Forum may have some advice.
The outer face is thiner than the inner face on one rotor. That is the part the brake pad presses upon is thinner on one side than the other by about 1/16th of an inch, the inner part is thicker by about the same amount.
I have seen this before from time to time but usually on cheap rotors. In the past I have simply asked the supplier to replace for another. These were mail order and I wonder if it really makes a difference.
These rotors are for replacement with a corresponding paint to cure the hat rust problems and a set of Ceramic pads, nothing is wrong with my brake system only 25k and I don't want to open a potential problem.
The one on the right is the problem, upper face.
thanks for any advice
Barrier:
The outer face is thiner than the inner face on one rotor. That is the part the brake pad presses upon is thinner on one side than the other by about 1/16th of an inch, the inner part is thicker by about the same amount.
I have seen this before from time to time but usually on cheap rotors. In the past I have simply asked the supplier to replace for another. These were mail order and I wonder if it really makes a difference.
These rotors are for replacement with a corresponding paint to cure the hat rust problems and a set of Ceramic pads, nothing is wrong with my brake system only 25k and I don't want to open a potential problem. The one on the right is the problem, upper face.
thanks for any advice
Barrier:
Last edited by Barrier; Oct 1, 2006 at 10:56 AM.
Instructor
Joined: Feb 2006
Posts: 148
Likes: 2
From: Saratoga Springs New York
Have to be careful here. What you're seeing is poor quality control. Chance are those two rotors were machined by different companies.
From strictly a braking perspective as long as the braking surface areas are the same as original, and by the same I mean surface area and material of construction, the car will brake the same. That the pads sit 1/16" off to one side won't make a difference. The tricky part is clearances. Gotta make sure there is sufficient clearance between the rotor surfaces and the caliper. Make sure you take expansion into account.
Unless you have to use them, personally I'd return them because if the inner and outer thickness dimension is different from rotor to rotor, it is possible other dimensions are also different---again gotta be care of clearances and materials of construction. Different MOC will result in different frictional coefficients and possibly noticable braking.
Another thing to consider is if you ever consider resurfacing your rotors, you have less metal on that one side. Also under extreme braking -- assuming you track the car, the heat gain may (not sure)give some issues because you have slightly less mass on the one surface. It's been a long time since I've done heat transfer calculations.
Hope I've helped. Did you mail order them from a Chevy dealer of aftermarket saying they sell OEM parts.
From strictly a braking perspective as long as the braking surface areas are the same as original, and by the same I mean surface area and material of construction, the car will brake the same. That the pads sit 1/16" off to one side won't make a difference. The tricky part is clearances. Gotta make sure there is sufficient clearance between the rotor surfaces and the caliper. Make sure you take expansion into account.
Unless you have to use them, personally I'd return them because if the inner and outer thickness dimension is different from rotor to rotor, it is possible other dimensions are also different---again gotta be care of clearances and materials of construction. Different MOC will result in different frictional coefficients and possibly noticable braking.
Another thing to consider is if you ever consider resurfacing your rotors, you have less metal on that one side. Also under extreme braking -- assuming you track the car, the heat gain may (not sure)give some issues because you have slightly less mass on the one surface. It's been a long time since I've done heat transfer calculations.
Hope I've helped. Did you mail order them from a Chevy dealer of aftermarket saying they sell OEM parts.
Team Owner
Joined: Jul 1999
Posts: 50,808
Likes: 10
From: Buy USA products! Check the label! Employ Americans
far as I know OEM are made in Brazil and NAPA are made in Canada for 25 each. He probably buy the non GM rotors cheaper. He is also in viloation of his franchise agreement. They NAPA's are good as OEM. It must be a fluke. Buy NAPA's for 25 ea. What did he charge you?
Thread Starter
Drifting
Joined: Sep 2001
Posts: 1,875
Likes: 27
From: Long Beach NY
No these are genuine GM Made in Canada Rotors. #1-88925550 GR.5.809 1#18A949 8703 all on the box
Parts are from a reliable GM Dealer.
I am sure there will be no problem getting a replacement.
I am concerned about matching up a new one though with the good one.
I was never in doubt that these were GM. I also am aware that a Dealer cannot check every part that goes through their hands. I am surprised about Quality Control by GM. I could accept this from some of the Ebay parts or discount parts suppliers not GM.
My original question was really of a "does it make a difference nature" since I had not seen mention of this on the Forum before. Sometimes I tend to get a bit crazy on potential problems when it comes to my Cars or Bikes.
Forum member BobST1100 clarified the potential problems.
Anybody have any other similar experiences with GM parts? Is this a trend with commonly replaced parts, Filters,Plugs,Pads,?
I hope not.
Barrier
Parts are from a reliable GM Dealer.
I am sure there will be no problem getting a replacement.
I am concerned about matching up a new one though with the good one.
I was never in doubt that these were GM. I also am aware that a Dealer cannot check every part that goes through their hands. I am surprised about Quality Control by GM. I could accept this from some of the Ebay parts or discount parts suppliers not GM.
My original question was really of a "does it make a difference nature" since I had not seen mention of this on the Forum before. Sometimes I tend to get a bit crazy on potential problems when it comes to my Cars or Bikes.
Forum member BobST1100 clarified the potential problems.
Anybody have any other similar experiences with GM parts? Is this a trend with commonly replaced parts, Filters,Plugs,Pads,?
I hope not.
Barrier
Instructor
Joined: Feb 2006
Posts: 148
Likes: 2
From: Saratoga Springs New York
I've not run into this problem buying OEM parts in the past, but this is my first American car in over 25 years....I'm into Saabs. Consistancy from a car Mfr is why I tend to buy OEM especially when I have a time limit on my project. Aftermarket is another story altogether!
I don't know for sure but it wouldn't surprise me if GM uses several suppliers for each market ... Just in case one decides to go on strike or out of business... Never put all your eggs or 'rotors' in one basket.
Sorry man!
I don't know for sure but it wouldn't surprise me if GM uses several suppliers for each market ... Just in case one decides to go on strike or out of business... Never put all your eggs or 'rotors' in one basket.
Sorry man!
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Thread Starter
Drifting
Joined: Sep 2001
Posts: 1,875
Likes: 27
From: Long Beach NY
What Great Dealer Service got an email yesterday, new Rotors and pickup order arrived today. New Rotors look fine.
Fred Beans
Cannot beat Forum Sponsors.
Barrier
Fred Beans
Cannot beat Forum Sponsors.
Barrier
Last edited by Barrier; Oct 4, 2006 at 05:39 PM.
Melting Slicks
Joined: Mar 2003
Posts: 2,512
Likes: 49
From: Franklin IN
Originally Posted by Barrier
No these are genuine GM Made in Canada Rotors. #1-88925550 GR.5.809 1#18A949 8703 all on the box
Parts are from a reliable GM Dealer.
I am sure there will be no problem getting a replacement.
I am concerned about matching up a new one though with the good one.
I was never in doubt that these were GM. I also am aware that a Dealer cannot check every part that goes through their hands. I am surprised about Quality Control by GM. I could accept this from some of the Ebay parts or discount parts suppliers not GM.
My original question was really of a "does it make a difference nature" since I had not seen mention of this on the Forum before. Sometimes I tend to get a bit crazy on potential problems when it comes to my Cars or Bikes.
Forum member BobST1100 clarified the potential problems.
Anybody have any other similar experiences with GM parts? Is this a trend with commonly replaced parts, Filters,Plugs,Pads,?
I hope not.
Barrier
Parts are from a reliable GM Dealer.
I am sure there will be no problem getting a replacement.
I am concerned about matching up a new one though with the good one.
I was never in doubt that these were GM. I also am aware that a Dealer cannot check every part that goes through their hands. I am surprised about Quality Control by GM. I could accept this from some of the Ebay parts or discount parts suppliers not GM.
My original question was really of a "does it make a difference nature" since I had not seen mention of this on the Forum before. Sometimes I tend to get a bit crazy on potential problems when it comes to my Cars or Bikes.
Forum member BobST1100 clarified the potential problems.
Anybody have any other similar experiences with GM parts? Is this a trend with commonly replaced parts, Filters,Plugs,Pads,?
I hope not.
Barrier
