New Front Rotors

Subscribing to thread. I bought R1 Concept (drilled & slotted) rotors many moons ago for my Tundra and they work flawlessly. The Tundra has many TSBs out on their front rotors because they suck so bad also. My CX-9 has made it 35K so they are, well, OK I guess. Tundra can't make it 5K without stocks warping. Looking to do R1s again or cryo Powerslots. I have Hawk HPS pads on the Tundra and I'm looking to do Grand Sport or Green Stuff pads on my CX-9. I sure wouldn't like to order the wrong part number.
 
Chuck H said:
Do you happen to know the correct part number and the wrong number that a lot of places are selling?

Just wondering because I was looking at both TireRack and R1Concepts. The front rotors that Tire Rack lists are all variations on a 45080 number, while R1Concepts seems to list all variations on a 45045 number. The rear rotor and front and rear pad numbers all seem to agree between the sites, so I was wondering which front rotor number is correct. I'm guessing that the 45045 number is wrong, since it seems too cheap, and is also listed as the rotor for various 626, 929, and protoge models. And I'd hope that the Cx-9 uses bigger front rotors than a 626, since it probably weighs 1000 lbs. more.

Also, it looks like Tire Rack just got Power Slot rotors for the Cx-9, but holy crap are they expensive.
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Do not buy the 45045 number for the front rotor, it is for a 626, and I know this first hand. It is not the same diameter and "will not" work as only 1/4" of your brake pad will make contact.

The 45079 is the correct rear and the 45080 is the correct front. Tire Rack has the correct parts. I bounced the part #s off centric's website and they do correspond. Of note, I did receive a dropped front rotor from centric. I called and sent pictures and they comp'ed me a new rotor w/o having to send the bad one back.

My rotors and brakes are holding up well. My rotors do not show any major scoring and the pads have plenty left. I recently took my 9 to Sardinia and drove the roads there. Let me just say that a straight road is hard to find there. I rode my car hard, up-shifting and down, with major brake use. Still no shudder in the rotor/brake assembly after 15k use and have not experienced any fade; I just noticed a minor coolant odor as the car got warm.

Changing the rotors and pads was the best thing that I ever did to my 9. Do be careful though that you do put the correct torque on the rims or you may end up with warping.
 
Thaumaturge:
I agree with what you said. However, people will continue to say "warped rotor" no matter how hard you try.
I gave up longer ago trying to explain it to people I talked to.
They always gave me a are-you-sure look.

Proper break-in would also help reduce chance of "warped rotors".

German vehicles (such as BMW/M-B) use softer rotors. Thus, no "warped" rotors, but way more brake dust.
(Have you ever wonder why German vehicles always have dirty front wheels?)
The worst part about it is $$$. You need to replace pads and rotors together every 15K miles or so.
 
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Lindyrect said:
What was the reasoning mihalis? Just curious.
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The black does not really protect from corrosion (minor detail but still annoying) and when (primarily) cold and not braking aggressively, the steering wheel vibrates (at high speeds). Some people call this a warped rotor, but we all know that is not the case. At autocross, people have commented how well they work with the Hawk pads, but let's be honest, I do about 3-4 autox a year, and a lot of highway driving, therefore I get the annoying vibration at highway speeds unless I hammer on the brakes. If you are going to go with Hawk pads (which I highly recommend), I would get a smooth rotor, that is what Hawk pads prefer, smooth surfaces, not slotted or drilled. Again, speaking from experience in a combo I tried in my BMW.
 
Can somebody post a writeup on changing the brakes? I have done it before on a few other vehicles. I'm thinking of going with the powerslots. The brake pulsing at 30K miles is driving me crazy. It seems to get really bad on long downhill stretches of highway. I'm probably going to just do the fronts and see if that takes care of the problem.
 
Mine were not tough at all. Just make sure you have a good fitting Philips Head driver. I used an adapter to connect to my socket wrench, used an extension for better leverage, pushed in an turned, they came off pretty easy. They did make some squeek noises so I think they were on there pretty good, no way I could get them off with regular Phillips Head screw driver.

Also, FYI, I sprayed them with WD40 before as well and let that soak for about 10 mins, but I am not sure if that helped and how much actually penetrated behind the screw.
 
Has anyone attempted the "bedding" procedure on cx-9? I've never tried the procedure on any car, too nervous that it would warp the rotors considerably and immediately. I had VW's in the past with rock solid oem rotors that would go 80k with reckless daily driving no problem, no shutter.

Also, on our CX-9's, what's the point of putting the rotor screws back in? They really are completely useless, in my opinion.
 
helbigtw said:
Has anyone attempted the "bedding" procedure on cx-9? I've never tried the procedure on any car, too nervous that it would warp the rotors considerably and immediately. I had VW's in the past with rock solid oem rotors that would go 80k with reckless daily driving no problem, no shutter.
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Bedding procedure should just be like any other vehicle and should not warp the rotors at all. It's a controlled bedding process. Just think of how well brakes have to stand up to daily driving.

helbigtw said:
Also, on our CX-9's, what's the point of putting the rotor screws back in? They really are completely useless, in my opinion.
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I would leave the rotor screws off. They come standard on honda vehicles as well and is part of the manufacturing process to keep the rotor in place. Those screws are so soft and with brakes going through multiple thermal cycles, those screws will rust shut and you'll have to drill them out the next time you need to remove the rotors.
 
You just changed my life forever

I consider myself a very knowledgable car guy , and so I was very skeptical when I read your post here yesterday. How could I have been wrong all my life? How could almost everyone on every car forum I have ever read over the last 15 years be wrong? How could most mechanics be wrong? But I was.
I came here looking for info on where to order cheap rotors after my local service station quoted me $435 to change front rotors and pads. I always did my own repairs before I had 2 kids and a busy job, so I decided not to get ripped off this time- I would do this simple job myself. I have been putting this off for 20,000 miles... as my brakes have been pulsating something fierce for the last 20k miles and I am now at 40k. (Original rotors and pads, and even tires since I have dedicated snows during winter months)
Then I read your post, and I read the real article you linked to. It sounded logical, and I have heard similar theories over the years but I always dismissed them as half-truths.
I was about to place my order for $200 worth of parts, when I decided, what the hell- what have I got to lose?
So i just went out to the 4 lane road by the bay, and got up to 60 and slammed those brakes to the point of the ABS just kicking in. Down to 1st gear or so, then I repeated 6 times.
HOLY F'IN s****!!! My rotors were instantly about 50% less "Warped"!!! I realized this means they were never warped of course. But I can't see any weird deposits on the rotors! This is MADNESS. ANyway, I figured since I drove 20k with these deposits, I needed to do a few more hard stops maybe. I have gone way beyond what this solution is supposed to control.
So I did it two more times. 8 hard stops. 1/8 of a tank of freakin gas! Probably used up an 1/8 of an inch of brake pad too. But you know what? If my seriously shuddering brakes were at level 10, now they are at level 2. Yes, I still can notice them, but not when stopping normally. (unlike my BMW which has never had a brake shudder in its life as the rotors are made of softer metal)
Mr. Thaumaturge, you changed my life.
And I am going to post this as a new thread too so others can read this.
Thank you. We need to tell everyone on this forum who is wasting tons of money for no reason, just like you said!!!

/bill




Thaumaturge said:
Contrary to very popular belief, there is no such thing as a "warped" rotor thick or thin caused by normal use. Even tightening the lug nuts past spec will only cause the rotor to conform to the shape of the wheel assuming it's the stronger element of the two.

Check out this article from a company involved in racing for more detals: http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

To summarize, brake judder/shudder is caused by physical changes in the surface of the brake rotor due to heat experienced in normal stop and go driving. The more agressive you are with sudden stops, the faster these changes can occur. Particles of cementite are formed in the surface of the rotor that are harder and result in less friction. Because the particles are not formed uniformly over the surface, you wind up with uneven friction and the characterstic pulsating effect.

Before replacing your rotors or pads, try this procedure known as bedding the brakes (you should also do this for new brake installs):

Locate a long stretch of road several miles long.
During a period of little traffic (late night) on this road, get up to 60 mph and brake medium hard down to below 40 mph, then go back up to 60.
Repeat this process 6 times without stopping. It's important to never stop.
Yes, your brakes will get very hot, stink, and maybe even smoke. They will probably fade too, so be careful. Keep in mind that older brake fluid may boil under these conditions and chemically change. If fade continues, get the fluid replaced.

Once done, drive without braking at speed for at least a minute or two to cool everything off.

What you're trying to do is to burn off the cementite or at least create a uniformity of deposits to eliminate the judder. I have routinely used this procedure on all my vehicles for 20+ years with good results. I have never had to have a rotor turned to eliminate judder though one can understand that shaving off a layer of metal would also get rid of the cementite deposits.

As always your mileage may vary.
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What did you guys do with your old rotors? Can they be recycled as scap metal? They weigh a ton, not sure I want to put them in the trash.
 
not_too_shabby said:
What did you guys do with your old rotors? Can they be recycled as scap metal? They weigh a ton, not sure I want to put them in the trash.
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That's where mine ended up - in the metal recycling bin at my local landfill / recycling center.

bill42....besides the procedure to "un-warp" your rotors, some have mentioned that it's not a bad idea to change/flush your brake fluid after doing this procedure due to the high temperatures generated by the brakes that can stress the fluid.
 
Got the new front centric rotors, going to try the swap on Sunday. Bill42 - I'm thinking Ocean Bay Pkwy for the 'bedding' procedure..LOL. I see you're from LI as well.

wish me luck
 
Stripped 1st rotor screw on first attempt...DEF want to have the phillips socket for impact wrench or air ratchet if you are trying this yourself. Gotta take it to the Mazda stealership now. Horrible, so miserable. Then later today, the side view mirror controls broke. I can move mirrors up/down, but not right/left. I don't think this would be a fuse/relay issue as that would result in a complete fail, no?

Any help out there from my fellow 'Niners'?

Thanks
 
I got 3 of the screws out without much fuss using my cordless drill, although it takes a lot of torque to remove the screw. The key seems to be to have the right size bit and to be pushing the drill hard into the screw so that it doesn't strip. I got sloppy on the last one and that is the one I stripped. Drilling the screw out was actually pretty easy. After drilling on it for a couple minutes I was able to just jam a flathead screwdriver into the hole and unscrew it.
 
That is good to know...9 is the wife's car and can't put it out of commission, so have to take it to get rotors done. Still have the seat belt recall to get addressed, and now the side view mirror issue, so I figured I might as well bite the bullet and go to the dealer. I still have to call them for a quote, so we'll see. Also, can only get the rotor screws from dealership, and parts desks aren't open on Sunday's here in NY.
 
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