Now that's a serious issue. I wouldn't drive the car until Satuarday. I'd look like your avatar right now if i were you . I can't beleive how stupid these service guys are !!!!!

 

This is most likely due to a warped right front rotor. Good luck getting them to cover it under warranty. They'll probably claim you were abusing the brakes.

Pete: I don't think you have anything to worry about in terms of premature wear or damage to your brake pads or rotors. Generally, dirt and grime lodged between the rotors and pads is not the primary cause of squeal. My mechanical engineering professor back in grad school had projects on brake squeal funded by the automotive industry. It is NOT a simple problem, and there's no way auto companies would spend tens of thousands of dollars to fund research on this issue if there was a quick fix. Generally, squeal occurs when the properties of the friction interface (between rotor and pad) change such that a stick-slip type of excitation energizes the rotors during braking. The rotors then vibrate at one of their natural frequencies giving off a high-pitched squeal. The problem lies in how to effectively change the friction interface between the pads and rotors so that stick-slip excitation doesn't occur, or damp the vibration of the rotor so that it doesn't radiate as much. Machining the rotors may help, as will changing the pads. Some have reported that the "anti-squeal" grease helps, at least temporarily, but just as many people report no improvement at all.

 

thanks for the info rx8 buckeye.

Very informative. Would changing the brakes to cross drilled/slated help? Maybe it's a overheating issue?

 

Has anyone correlated the squeaking to painted calipers or rotors (centers and edges only Duh!)? I have *one* squealing brake, it happens to be the one that I painted (as above). Never got around to the others yet (nasty story about paint can and running over it with front tire...).

 

I'd like like to know why they squeal period. What's it about the quite cars' brake designs that make them not squeal?

rx8cited

 

I don't think they're related. I never touched mine prior to them squealing.

rx8cited

 

It depends if you got any paint on any of the friction surfaces (pads/rotors), then yes that is the cause due to a special epoxy in most high temp paints. Your only hope is resurfacing or a bath in acetone.

 

As someone mentioned, it is from "stiction". As the pads ride the surface of the rotor, it is not a smooth continuous movement, but a series of stick/slip/stick/slip movements. The duration of the stick vs slip intervals determines the frequency and amplitude of vibration that is induced. This then gets transmitted to other parts of the braking system. Then, depending on the properties of those parts (weight, size, thickness, shape, elasticity, etc...), other vibration frequencies can result.

As I've said before, this is common to ALL disk brakes, and Drum brakes also for that matter. It's just the nature of the materials. The difference between a squeaky brake and a "non-squeaky" one is merely the frequency and amplitude of the vibration.

The presence of brake squeal does NOT necessarily cause bad braking NOR does it necessarily result in premature wear or failure of brake components. Pete is jumping to conclusions that are unwarranted.

 

The only conclusion that i jumped to is that it irritates the hell out of me. You can say all brakes give out a "squeaking noise: , but mine is equivalent to nails on a chalk board. The brakes are warranted for the first 20, 000km. I already had them changed once due to this issue. No charge

 

Thanks for your explanation.

Squealing can be very annoying, though. I wonder why Mazda is not using the "quite" material on our pads?

I wonder how much warranty money auto manufacturers spend dealing with customers annoyed by their squealing brakes? I'd think that they would rather spend that money researching how to make quite brakes that work well, don't squeal, and keep customers happy.

I know it can be done, I've had cars that did not have squeally brakes.

C'mon Mazda, please surprise us with a fix soon.

rx8cited

 

Pete - you indicated you wanted to resolve the issue to prevent "major damage down the road". I'm just saying that if it's typical brake squeal, that's probably not something you have to worry about.

Complaints due to the noise are certainly legitimate. I can understand your frustration and I'd be clamoring for a fix also if I had a nasty loud squeal.

 

Manufacturers do end up paying a lot of warranty costs to please customers who complain about brake squeal (among many other things--even brake dust!). And as I stated previously, they DO sponsor quite a bit of research aimed at gaining a better understanding of this problem. Unfortunately, there are a number of obstacles in the way when it comes to solving the brake squeal problem.

1) It is very difficult to pinpoint the root causes of brake squeal and the conditions under which it occurs. It is a phenomenon sensitive to many variables, including the pad and rotor material properties, surface characteristics, mass and stiffness of the rotor, temperature, humidity, etc. It is very likely that there are many different causes of brake squeal among RX-8 owners. This makes it difficult to come up with a solution that will fix brake squeal across the board.

2) Most of our RX-8s didn't squeal from the day we took delivery. This implies that something related to the pad/rotor wear or material degradation is invoking the problem. These are noise factors that are extremely difficult to predict from a CAE (computer aided engineering) standpoint. It's virtually impossible to accurately predict the friction interface characteristics after a given amount of real-world driving.

3) Unfortunately, there is no such thing as a "quiet" rotor or pad material, especially when you're dealing with aggressive friction materials that deliver outstanding braking performance. The "quiet steel" that is advertised (like in the F-150 commercials) has a special polymer coating that absorbs energy through shear strain. It's not practical to coat a rotor because a) the coating would reduce coefficient of friction between pad and rotor and would wear off quickly anyway, and b) the high temperatures experienced by the rotor would most likely loosen the bond between rotor and any coating.

The biggest issue, in my opinion, is that there is just too much variability (car to car, driver to driver, climate to climate, etc.) to design a brake system so robust that no one experiences brake squeal. Could improvement be made? Probably so, but it's not an easy fix.

 

I should be good then....I cleaned up after myself with "high strength acetone"..so it said on the label

 

I had an '87 BMW 528e that I did a *lot* of brake hardware replacements on. I can comment on squeek, wear and warpage issues. This isn't directly responding to anyone in this thread, just providing some experience and info.

Squeek - All disk brake pads vibrate. Sometimes this vibration is at the right frequency to cause brake squealing. Different types of pads (asbestos/non-asbestos/metal) vibrate in different ways, and may be more-or-less prone squealing. You have to try to eliminate some of the vibration and dampen the rest. You reduce the vibration by beveling the edges of the brake pads before installation. I tried this once with a dremel, but it was overkill. I good 10" "flat bastard" file will easily put a nice bevel edge all the way around the pads, and will get rid of the majority of the noise right away. Next, you need some brake pad shims. The stuff I used to use was like very thick self-adhesive foil. You cut it out in the right shape to fit the BACK side of the pad (duh!) and stick it to the metal backing. After sticking on the shim material, I coated the entire (now shimmed) metal backplate, along with the 'ears' that stick out on either end, with hi-temp anti-seize paste. Now assemble the pads into the calipers taking care not to get any of the anti-seize on the brake pad surface or on the rotor surfaces. Voila. No more squealing brakes.

Wear - This is highly dependent on the type of pad you use. On my old BMW I initially dissed the OEM pads due to dust, and spent a lot of time, money and frustration on (Axis/PBR/Repco) 'Metal Master' and 'Deluxe' pads. The 'Deluxe' pads are low-asbestos, long lasting, squealed until I did the above procedure, and were very unsatisfactory in their braking performance. They didn't wear grooves in the rotors at all, but were prone to warping rotors due to poor heat dissipation. The Metal Masters (aka Metal Bastards) squealed like a tortured pig, and chewed up the rotors and spit them out derisively. The OEM pads generated more black dust than a coal mine, but had excellent pedal feel, short stopping distances, and treated the rotors humanely. Moral: All brake pads are *not* equal, and it's likely that Mazda will go through several part numbers as they work out the best setup for the RX-8, just as BMW did with the 5 series in the mid 80's.

Rotor Warping - I learned the hard way with this, too... Unlike with the pads, the OEM parts were not the best choice. I went through 3 sets of Brembo front rotors in short order - one set were warped by the 'Deluxe' pads, one set were eaten by the Metal Masters, and one set were destroyed by me being too aggressive in trying to 'bed them in' - those warped in 1 day and were replaced in under 3 weeks (my bad). I then found my best rotor choice ever - ATE 'PowerDisc' slotted rotors. The purpose of drilled or slotted rotors is NOT to dissipate heat. In fact, drilled rotors are bad from a thermal dissipation standpoint because there is less mass to convert friction --> heat and dissipate it, and the holes can be points for stress cracks to develop. Slotted rotors are better, and accomplish the same thing. As pads clamp against the rotor, they release gases. This buildup of gases can cause 'pad float' and loss of braking effectiveness, and a layer of brake dust doesn't help matters either. Having slots or cross-drilled holes allows the gases and abraded dust to escape, providing better braking effectiveness. I now have this same type of rotor on a VW GTI VR6 and it's wearing and behaving a lot better than the stock ones did.

Rotor warping can easily be caused by driving technique. Several hard stops in a row can superheat the rotors. Coming to a full stop and keeping a foot on the brake can cause a 'hot spot' where the pads clamp down, and the uneven cooling can warp the rotor. Likewise, running through standing water with overheated rotors can shock-cool them, leading to warping or cracking. The type of pad can also affect it, as I pointed out above. It's highly unlikely, though, that it's a manufacturer defect. One or more warped rotors can cause serious front-end vibration under light braking, and it cannot be fixed by machining ('turning') the rotors - if you try to turn the rotors to 'true' them, they'll be warped again in a couple of hundred miles. If you every have a warped rotor, always replace (never repair) and always replace in pairs (never just one side).

My $0.02. HTH. YMMV. HAND.

:D

 

Great info and we appreciate the post. ^^

I agree that slotted rotors are the way to go if you are planning on replacing them.

 

Thanks !!! ^^^

 

Squeaking brakes would irritates the hell out of me too just like pop ups!

 

That problem I can solve: http://www.mozilla.org

In re-reading my earlier post, I realise I didn't finish my thought on the ATE PowerDisc rotors.... The slots on those rotors have slightly raised edges with respect to the surface of the rotor face. This slight 'scraping' (for want of a better word) of the face of the pads keeps them from developing the ridges that score the rotors.

Here's an informative page with a flash animation link (audio in German) (sorry for the long URL): http://www.conti-online.com/generato...r_disc_en.html

For some reason their USA catalogue comes up in German, and I can't read it well enough to figure out the menus. It looks like they have PowerDisc rotors for some Mazdas, but not the RX-8 yet. It took them a couple of years to come out with the ones for the newer VWs, so there's some hope that RX-8 fitments are in the works.

 

Thanks for all the good info. I love those groovy rotors ........ I wonder if they'd solve our squeals?

To see the catalogue in English, go to this page:
http://www.conti-online.com/generato...logues_en.html
Then select "Replacement parts (USA only)", then in the new window that opens, press the "Start" button on the upper left side of the screen next to the "Home" button.

Now if we could figure out how to get that flash video to play in English .

rx8cited

 

FYI:Mazda says brake squeal fix to be available in October.

rx8cited

 

Oh stupid is not all...
When I went to Mazda, the service manager told me he would do a: "One time only fix it". So I told him I was going to put a after market brake kit on the front and back, they should hold up better in the heat. Then he tells me: "that would void your warrenty". I tell him WTF are you talking about man? You just said: You will do a one time only free be and now you tell me that its under warrenty? Make up your mind. This kind of things go out you know its like tires, springs, gass, brakes and oil. So you are they OR are the not under warrenty and how the F**K do you keep your job if you dont know what the hell you are talking about?..... "Well lets go into my office and let me see what I can do for you".............


Oh yea they fixed them for free...

 

lol . Good job DOMINION !

 

I was at the dealership for an oil change and talked about my brake noise. It just started on my car; I have 7000 miles on her.

Anyway, the service department told me that Mazda is aware of the "noise" problem and they are looking into. Probably will be replacing the pads. Whatever that means...

 

they've been telling me that forever.

 

^^Yea and Mazda did a press release on this too some time back...