Brake failure - totalled my MS3

[willi]

note Hawk HPS has MOT of 750F, XP12 has MOT of 1950. there is also a XP16.

http://www.ctbrakes.com/faq/faqanswers.html#_4

Stoptech list MOT for many of the popular pads:
http://www.stoptech.com/products/high_performance_pads.shtml

http://store.zeckhausen.com/catalog...d=146&osCsid=f730884822417a8ea5a118f7f08e7d5b
quote:"Hawk HPS high performance street pads have low dust, low noise, and low rotor wear. Slightly higher in friction level than Hawk Ceramic pads with a similar MOT of around 750F. Not recommended for track use, as their friction level falls off rapidly when the MOT is exceeded."

description of Hawk HPS
http://www.hawkperformance.com/performance/hps.php

you guys are brave going 130MPH down the straight and counting on a street pad to stop you. I drive a slower / lighter car and have pads with twice the MOT.

 

[GDorris]

you guys are brave going 130MPH down the straight and counting on a street pad to stop you. I drive a slower / lighter car and have pads with twice the MOT.

I appreciate your concern, but I was using HP plus, not HPS. They performed fine - and wore reasonably well - 3.5 track days and 6,000 street miles. That said, Hawk Blue pads would have been the better choice but I do not know if they were/are available for our application.

 

[GDorris]

inner pads wears faster is most likely due to heat. inner pads runs hotter (out pads gets better cooling), and wear faster. fix is either a brake duct or more heat-tolerant (higher MOT) brake pads. ie. track pads.

Heat, huh? I think not. Think a moment about ABS repeatedly hammering directly on the inner pad 12 - 15 times per second. Then think about the caliper that has to move instantaneously in order to transfer pressure to the outer pad. Have you held one of these in your hand? They massive, as in lots of mass = lots of inertia. There must be at least 5 pounds of metal that has to move before the outer pad moves, while the inner pad only has to move the piston. Then think about caliper flex that, while small, would also reduce the pressure transferred to the outer pad. Then think about ABS repeatedly applied.

If by heat you mean more friction on the inner pad, then we agree. But if you mean heat because of airflow keep thinking.

I agree that the heat range of these pads was insufficient and that Hawk Blues would have been better.

 

[psyshack]

I don't think it was a abs dump at all. I think it was a fluid boil and master cylinder bypass.

While the absence of brake pad material would have cut down on total braking force. It should have still ground the hell out of the pads and disc.

If brakes stop working on these cars cause the pad material is gone or near gone. I'm getting rid of mine very quick!

I took mine out to test the abs threshold / dump when it was new. I did this testing on a large pad hydroplaning. With the car up on water and sliding like it was on ice. I never lost the pedal. Speeds were over 100 mph.

Something doesn't add up here at all. I think the culprit was the master cylinder. Boiling fluid or the lack of it. Ive seen to many car roast there brakes. Make the disc glow and spit the pads out and still bury the caliber piston into the disc. If the master cylinder res. is full it should all but spit the piston out of the caliper's. And there is no way a snow dump or hydroplane dump will put a brake pedal on the floor. Thats one of the times the braking balance kicks in and abs modulation goes high speed. Not to the floor.

If this is a trait of the 3 it shouldn't be allowed on the road. With this excuse / mode of failure.....

 

[RPI-Speed3]

Wow, sorry about your loss... Glad you're OK.

I noticed you meantioned Hawk brakes... I will never put those brakes on any of my cars ever again!! They are way too aggressive and eat up rotors like nothing. Those pads are not recommended for daily street use since they have a high rate of wear. They brake awesome, but need to be inspected frequently due to high rate of wear of pad and rotor...

Lesson, I would stick with stock brake pads or a milder pad...

I put those on my previous car (Miata) and I assumed they would last at least a year... 8 months later, my rear rotor was half its thickness and the hawk pad was almost to its rivets on the inner pad.

Since then I've only used OEM Mazda pads and have never been happier...the stockers handle autocross and track days very well...

This is absolutely incorrect. The stock pads would have worn MUCH faster on the track than the Hawks he was running. He did the right thing by switching out the stockers in favor of a more aggresive compound. As he noted, his only mistake was not checking the pads frequently enough.

Second: Thank the good lord you are still walking today. I'm not a religious guy but I'll be praying for you on this one. A very low percentage of people walk away from a crash at that speed. As a fellow track driver, I'm ecstatic you are still with us.

Now all that being said, this ABS issue is extremely scary. This car has more electronic smarts than the space shuttle, and still was not smart enough to help you on this one. Mazda definitely needs to hear about this, I can put you in touch with a Regional Rep if you would like me to. This system is there to PROTECT you, here it ALMOST KILLED you. I noticed uneven pad wear with my car as well @ VIR running Carbotech XP8s. You can minimize by braking earlier and going into a corner slower. However, if you routinely enter turns hot and slam on the brakes, the uneven wear WILL happen eventually.

Mods: I think we need to sticky this. Everyone who does track days should read this.

 

[staticlag]

Hi!

I just read this tread and its pretty clear that the ABS system is NOT to blame. In your first post you claim that the ice terrain handling programming is what caused the brakes to malfunction, this really isn't the case at all.

Clearly:

1. In slippery brake conditions when a tire is not having traction on the surface it will "lock-up" because the force of the pads against the rotor are producing more usable friction than the road to tire.

2. Only in the above situation would the "brake dump" function activate because it would try and reduce the amount of pad-rotor friction until it was about equal to the tire - surface friction coefficient.


So heres how ABS would act on ice, or water or slippery road or whatever:

Car runs front right tire over ice patch. Since the ice is slippery the pad is able to lock the tire in a stationary position because the rotor-pad are producing more friction than the tire-ice. The ABS module senses that 3 tires are moving at a much greater rate of speed than the front right (which is stationary) so it dumps brake pressure to the front right in an effort to reduce the amount of pad-rotor friction to a level where the tire can have some friction on the ice.

THIS IS SAFE! THIS IS A GREAT SYSTEM!

Now what happened in this case is that dude went to apply brakes and pedal went to the floor. Not once was one or two or even three wheels granted enough friction to lock the tire and activate the ABS dump mode. Simply impossible.

I would appreciate it if you all stopped spreading rumors that ABS is harmful you are going to unnecessarily scare track and car newbies

 

[staticlag]

If theres anything that this thread stresses, other than to check every inch of your car, is the importance of a 5 point harness and track legal roll cage.

 

[Falconx84]

Hi!

I just read this tread and its pretty clear that the ABS system is NOT to blame. In your first post you claim that the ice terrain handling programming is what caused the brakes to malfunction, this really isn't the case at all.

Clearly:

1. In slippery brake conditions when a tire is not having traction on the surface it will "lock-up" because the force of the pads against the rotor are producing more usable friction than the road to tire.

2. Only in the above situation would the "brake dump" function activate because it would try and reduce the amount of pad-rotor friction until it was about equal to the tire - surface friction coefficient.


So heres how ABS would act on ice, or water or slippery road or whatever:

Car runs front right tire over ice patch. Since the ice is slippery the pad is able to lock the tire in a stationary position because the rotor-pad are producing more friction than the tire-ice. The ABS module senses that 3 tires are moving at a much greater rate of speed than the front right (which is stationary) so it dumps brake pressure to the front right in an effort to reduce the amount of pad-rotor friction to a level where the tire can have some friction on the ice.

THIS IS SAFE! THIS IS A GREAT SYSTEM!

Now what happened in this case is that dude went to apply brakes and pedal went to the floor. Not once was one or two or even three wheels granted enough friction to lock the tire and activate the ABS dump mode. Simply impossible.

I would appreciate it if you all stopped spreading rumors that ABS is harmful you are going to unnecessarily scare track and car newbies

welcome to the forum. I was very impressed with your post (esp considering it's your first here) up until the last line. This is a forum, it's meant for discussion. If we all agreed on what happened, it'd be a pretty boring place

 

[Vindikacione]

I know he didn't have time, but if he could do it again, would pulling up on the parking break help any? Somebody probably covered this, but after checking 5 pages, I just decided to (re-)ask the question. With that said, could he have drifted through the turn?

 

[Koenig]

I know he didn't have time, but if he could do it again, would pulling up on the parking break help any? Somebody probably covered this, but after checking 5 pages, I just decided to (re-)ask the question. With that said, could he have drifted through the turn?

if you know anyone who can drift a FWD car...... I'd love to meet them

 

[Koenig]

Drifting is pretty much emphasized by powersliding.

Some people just have enough horsepower to break the tires loose. and some people use the e-brake, but still have enough horsepower to keep the tires spinning.

with a FWD car, since you can't put any power to the rear wheels..... the only thing he could have done was got on the e-brake to snake the back end out...... but even then that's not to say he wouldn't have sent his car spinning or flipping out of control.

 

[Falango]

When you are going 130mph coming up to a turn, you just can't think fast enough to pull the e-brake. By the time you would think of that, you've probably already hit the wall, and had been busy praying for your life. Drifting through a turn of that degree, at that speed, is impossible, you need to stop watching NOPI.......A car, let alone an FWD car, cannot manuever a turn better when it's sideways with no traction, than when it's at proper cornering speed with 4 wheels of traction.

All the e-brake would have done is probably turned the car around and made him hit the wall backwards.

 

[ZoomZoomH]

sucks about the crash, glad you pretty much walked away from it

just curious, did anyone catch what brake fluid he used in conjunction to the R tires and the HP pads??

 

[Kooldino]

Man, that thing looks GREAT for 110mph crash.

Glad you're ok...but I'm sorry to hear about your misfortune.

 

[Falconx84]

sucks about the crash, glad you pretty much walked away from it

just curious, did anyone catch what brake fluid he used in conjunction to the R tires and the HP pads??

DOT 4 synthetic I believe....don't know brand

 

[GDorris]

When you are going 130mph coming up to a turn, you just can't think fast enough to pull the e-brake. By the time you would think of that, you've probably already hit the wall, and had been busy praying for your life.

Yeah, that's about how it was. Add the part about knowing I was in the air, would come to earth some time soon, and when I did it was going to hurt some more! Let me state for the record, when you hit something solid at 100+ MPH, it hurts RIGHT NOW!

 

[Falango]

Yeah, that's about how it was. Add the part about knowing I was in the air, would come to earth some time soon, and when I did it was going to hurt some more! Let me state for the record, when you hit something solid at 100+ MPH, it hurts RIGHT NOW!

And so I think it would, lol. I could only imagine that the few hundred feet your car traveled on the ground, while trying to get the car to slow down seemed to take about a half second, but I bet when you hit the wall and were airborne and tumbling, must have seemed like an eternity

When you are traveling that fast at a corner that you'd probably have to slow down to what, 50mph to take probably, you only have a split second to react to a situation, because the velocity your car travels at covers alot of distance ina fraction of a second, but really, there wasn't much you could do to avoid this collision, as you were coming into the corner that is. At that point, you are the passenger. I'm glad to see your car did it's job, it protected you well, and as Kooldino said, the car does look very well structurally after such an impact, horray for the MS3!

 

[ZoomVT]

wow. just saw this.
glad you are ok...

 

[Koenig]

Yeah, that's about how it was. Add the part about knowing I was in the air, would come to earth some time soon, and when I did it was going to hurt some more! Let me state for the record, when you hit something solid at 100+ MPH, it hurts RIGHT NOW!

I believe it....... I was involved in a motorcycle crash thanks to a jackass running a red light and clipping my bike..... the bike basically did a diagonal flip after he clipped the front wheel..... and it definitely hurt when I hit the ground and the bike on top of me (which broke my leg in 6 places)

even being in a car and surrounded by that "metal cage" hitting something at 100+ mph still has to hurt man. You have to thank god that these days while people build cars for speed, they STILL primarily build them to protect (2thumbs)

 

[RichB]

Wow... what a story. Glad you made it out of that crash. I have a question about checking the brakes. Since Mazda doesn't have any pad wear indicators, What is the best way the check them? Thanks