It's brake time

[FukuokaKid]

It's that time. Front brakes are down to <20%. Figured I'd just do all four since the wife has mentioned that she'd like more stopping power. I have front and rear EBC Yellow stuff and Motul 600 RBF ready to install.

Here is my issue(bang)... I have measured my rotor thickness variation as well as runout. All are within specs. Runout in particular is at ~0.001". But I have a very small groove in one of the front rotors.
Now do I...
A. Just replace the pads? No additional costs. And not worry about it.
B. Cut the rotors? Bench lathe may introduce more runout. I do not have access to an on-car lathe. $210 from the dealer.
C. Replace the rotors? ~$130 but could be $340 if the new rotors have some runout and I have to cut them. Rotors in mind are Centric High Carbon Premium Rotors.

Attached is a pic of the rotor with the small groove. Hardly noticeable. Please give me your thoughts. Thanks for looking.

 

[FukuokaKid]

My worst case scenario had come to life. Had a shop bench cut the rotors. Bad bad bad idea. They introduced so much runout that I do not want to drive the car at the moment. At any position, runout is at 0.01", 6.67 times Mazda's maximum spec. The shop is willing to re-do the cut. Looking for suggestion to go forward. Need to get the 5 back on the road asap.(argh)

 

[MarkVII88]

My worst case scenario had come to life. Had a shop bench cut the rotors. Bad bad bad idea. They introduced so much runout that I do not want to drive the car at the moment. At any position, runout is at 0.01", 6.67 times Mazda's maximum spec. The shop is willing to re-do the cut. Looking for suggestion to go forward. Need to get the 5 back on the road asap.(argh)

How many miles are on your current rotors? Are they original to the car? Why not just get better rotors that are going to stand up to your EBC pads for longer? That's what I would have done in the first place unless the rotors on the car now are nearly new. Centric high carbon are a good choice!

 

[flcruising]

You should have sanded, not turned the rotors. Hindsight
Have them re-turned (free hopefully), check runout, check thickness, if within spec, run with it. If not, replace them.

 

[Vasy]

I'd have left them as is. Now probably best to buy new set and get a refund on a cut.

 

[Orangutan]

As cheap as Centric rotors are, just buy a set of them.

 

[FukuokaKid]

Thanks for all the input. The rotors had ~50k on them. Ordered a set of the Centric High Carbons. Hopefully they don't take to long to ship. Meanwhile, the shop said they would recut them but no refunds. This is only after I pointed out that the their original cut was incomplete. There was a small amount of material at the outer edge that was not cut. This was on both rotors. Lesson learned I guess. Used to cut rotors with these guys all the time back in the day. This is the first time I'm cutting rotors this century. Haha! Hopefully no more issues. Fingers crossed.

For those that changed their rotors, was there a ton of rust on your hubs? How did you clean them? Mine were pretty rusty. I used a wire brush and 3m synthetic steel wool med to clean as best I could then coated with some superlube.

 

[Secondtyme]

Those don't actually look too bad, especially with at least 50k on them. There have been members on here who had to beat their rotors off in pieces they were so badly rusted. I'm planning on cold galvanizing mine when I replace the rotors.

 

[MarkVII88]

Thanks for all the input. The rotors had ~50k on them. Ordered a set of the Centric High Carbons. Hopefully they don't take to long to ship. Meanwhile, the shop said they would recut them but no refunds. This is only after I pointed out that the their original cut was incomplete. There was a small amount of material at the outer edge that was not cut. This was on both rotors. Lesson learned I guess. Used to cut rotors with these guys all the time back in the day. This is the first time I'm cutting rotors this century. Haha! Hopefully no more issues. Fingers crossed.

For those that changed their rotors, was there a ton of rust on your hubs? How did you clean them? Mine were pretty rusty. I used a wire brush and 3m synthetic steel wool med to clean as best I could then coated with some superlube.

I'm in Vermont so when I replaced front and rear rotors on our 2008 Mz5 at ~62k miles the hubs were quite rusty. I had a helluva time getting front rotors off actually. I had to beat them with a 4lb mallet until they shattered and then I could pry them off with a claw hammer. Pic of ruined rotor below. I used a wire brush and sandpaper to clean up the hubs and put a thin coat of anti-seize hi-temp on the outer edge of the hub before installing new rotors.

http://www.mazdas247.com/forum/attachment.php?attachmentid=204023&d=1377222307

 

[Silentnoise713]

My worst case scenario had come to life. Had a shop bench cut the rotors. Bad bad bad idea. They introduced so much runout that I do not want to drive the car at the moment. At any position, runout is at 0.01", 6.67 times Mazda's maximum spec. The shop is willing to re-do the cut. Looking for suggestion to go forward. Need to get the 5 back on the road asap.(argh)

I’m experiencing similar issues with a pair of rotors that I recently had bench cut (not OEM, 2nd time taking them off/on). I’m interested to see if the new replacement rotors resolve your issue or if you continue to have runout problems.

I too trust that shop that I took the rotors too. I mean, it’s not a manual effort. A machine does the job but I guess the age/condition of the machine could be a culprit. I dropped off and picked up so don’t know the actual final measure value – my mistake..

-Did you have the cut on a bench lathe or on-car lathe?
-If bench cut, did the rotors come off easily or did you have to pound it off?
-How was the rotor measure to get the .01” value (bench or on-car dial caliper reading)?
-After cleaning the hub, did you measure the hub for runout?

For those that changed their rotors, was there a ton of rust on your hubs? How did you clean them? Mine were pretty rusty. I used a wire brush and 3m synthetic steel wool med to clean as best I could then coated with some superlube.

My hubs were rusty as hell and I left it exposed to elements for a little bit before I got back to it so it was extra crusty. I used Rust-Oleum Rust Stripper + wire wheel and cup. There are a few spots, especially around and in-between the lug bolt and center bore, which was hard to reach so was not cleaned as thoroughly as I should. I'm going to pony up and get the 3M Roloc hub kit and try again to get a good clean surface. I hope this resolves it for me. Otherwise, I have suspicions it is something else that will involve more time/money.

https://www.amazon.com/dp/ (commissions earned)

 

[FukuokaKid]

Im experiencing similar issues with a pair of rotors that I recently had bench cut (not OEM, 2nd time taking them off/on). Im interested to see if the new replacement rotors resolve your issue or if you continue to have runout problems.

I too trust that shop that I took the rotors too. I mean, its not a manual effort. A machine does the job but I guess the age/condition of the machine could be a culprit. I dropped off and picked up so dont know the actual final measure value my mistake..

-Did you have the cut on a bench lathe or on-car lathe?
-If bench cut, did the rotors come off easily or did you have to pound it off?
-How was the rotor measure to get the .01 value (bench or on-car dial caliper reading)?
-After cleaning the hub, did you measure the hub for runout?

Rotor were cut on a bench lathe and came off relatively easy. Couple or taps with a small rubber mallet.
When I got them back the first time, initially replaced in the same position and used a on-car dial gauge to measure the runout. Even tried changing positions and each time it was ~0.01".
I did measure the hub runout after cleaning at <0.0005".

The shop cut the rotors a 2nd time and it is much better. On-car runout is coming in at <0.002". However, thickness is now at the absolute minimum for a cut at 23.78mm. Asked the tech what happen the first time and his only response was "I didn't cut them then". Anyway, Centric High Carbons should have been delivered to today. We'll have to see if they are any straighter.

 

[MarkVII88]

Any updates on the Centric High Carbon rotors? I'm interested to know since I'm considering them for my Mz5 when the time comes. Thanks.

 

[FukuokaKid]

Any updates on the Centric High Carbon rotors? I'm interested to know since I'm considering them for my Mz5 when the time comes. Thanks.

Sorry no updates yet. Probably going to install this weekend.

 

[Davicho]

Sorry Honolulu but I'm going to high jack your thread for a quick consensus opinion question while you provide feedback on your new rotors.

So I have a good amount of brake pad material left probably a good 50-60% but my bad OEM rotors are vibrating more then a female college student's sex toy. I've already turned them twice so they're done. My question is should I just buy two brand new rotors and slap them on and use the existing brake pads since there's plenty of life left on them or should I stop being a cheap bastard and just replace the pads with new ones? Opinions? Cons or pros? TIA

 

[MarkVII88]

Sorry Honolulu but I'm going to high jack your thread for a quick consensus opinion question while you provide feedback on your new rotors.

So I have a good amount of brake pad material left probably a good 50-60% but my bad OEM rotors are vibrating more then a female college student's sex toy. I've already turned them twice so they're done. My question is should I just buy two brand new rotors and slap them on and use the existing brake pads since there's plenty of life left on them or should I stop being a cheap bastard and just replace the pads with new ones? Opinions? Cons or pros? TIA

Decent pads are not very $$$ so I'd just get new ones. You'll kick yourself later if you dont.

 

[Davicho]

Decent pads are not very $$$ so I'd just get new ones. You'll kick yourself later if you dont.

Ok, fair enough. I have Centric ceramics and I have to say I was not impressed with their performance, it just feels like they lack bite. Would semi-metallic have a better bite? or which composite offers the best bite?

 

[MarkVII88]

Ok, fair enough. I have Centric ceramics and I have to say I was not impressed with their performance, it just feels like they lack bite. Would semi-metallic have a better bite? or which composite offers the best bite?

Carbon fiber or Para-aramid. When I do my brakes I'm going with Centric (Stoptech) Para-aramid pads and the High carbon or Cryo-treated rotors. Only 37k miles on the car now and OEM brakes are still doing OK.

 

[90210]

What should be expected life span ?

Mine is at 50k miles
I have owned her since new - June 2011

Brakes still feel as good as new

Appreciate thoughts

 

[Secondtyme]

Well I have put just short of 100K on the rotors that were on the car when I bought it, and the fronts are completely trashed (warped). The rear rotors are fine, but the pads needed to be replaced at about 85K. I replaced the front pads at about 50K but I have no way of knowing how old they actually were at that time.

 

[Silentnoise713]

Well I have put just short of 100K on the rotors that were on the car when I bought it, and the fronts are completely trashed (warped). The rear rotors are fine, but the pads needed to be replaced at about 85K. I replaced the front pads at about 50K but I have no way of knowing how old they actually were at that time.

Mileage is an inaccurate indicator for maintenance especially since you do some much HWY! You could theoriclaly roll down a million mile hill but that does not mean the rotor will last a million miles - execpt for the guy following you ? Boils (pun intended ) down to how hard and frequently you cook your brake and the maintenance condition (slider pins, calipers, brake fluid) of your brakes (in part due to how and where you drive).

For pads and rotor suggestion, this is independent of a model car. Best thing to do is read brake studies/review or read user reviews on tirerack. Whatever you select, there WILL be a compromise. I've learning there is no ideal pad b/c we all drive differently, in different environments, with different demands. Do be mindful that aggressive pads will need quality rotors.

I came across this site a long time ago but the reading stuck with me. Note that they are a retailer but their advice is spot on.
http://topbrakes.com/c/faq