Brake failure **video posted**
11/5/07 update. Video posted on YouTube http://www.youtube.com/watch?v=sx-zmGm3Kj4
Shot by a RX-7 tt two cars back
I totaled my Mazdaspeed3 at the track on 9/13. At the end of a long straight at a very high rate of speed, I hit the brakes and the pedal went to the floor. I pumped - nothing. I skidded off the track and hit a tire wall on the passenger side at somewhere between 100 - 110 mph. I am the luckiest guy I know. It has been three weeks now and I am mostly good to go. The car is toast.
No - my insurance is not going to pay. I will be parting it out and will post when and where in this thread.
Why did the brakes fail? Because I made an assumption.
I did not check the thickness of the inner pad and I ran out of pad! I assumed there was as much on the inner pad as the 1/3 -1/2 thickness I saw on the outer pad. Not.
Then something else happened - Under heavy braking, from what I have learned from talking to auto engineer types, this ABS system sensed braking on the LF wheel and not on the padless RF wheel, thought it was on ice, then dumped brake pressure in an attempt to drop down to braking threshold friction levels on ice. Every time I pumped the brakes, the same thing happened.....Crash! Skeptics should google "ABS dump mode" and do some reading before flaming. It was not brake fade or boiled fluid - BTDT.
So at this point it looks like my mistake caused the problem initially, and Mazda's design of the ABS ice software routine made it catastrophic. Bad combo.
Morals:
1. Never assume because you examined the pad thickness of the outside pad that you know the thickness of both pads! Check them both.
2. Never let your front pads get close to the backing plate on this car.
3. Never drive on the track more than you can afford to walk away from.
4. This car has a problem with ABS programming that showed up in a bad way on the track - be warned!
5. Brake pads for this car should have either wear indicators or sensors, given the consequences of running out of pad. They come with neither.
One last word - this car did a hell of a good job protecting me in the crash. Another last word - this thing kicks ass on the track. I highly recommend MS coilovers, Nitto NT-01 225/45 17 on 17 lb. 2006+ MX-5 wheels, MS CAI and Hawk HP+ pads, as long as you check pad wear closely. Mine lasted 3.5 track days plus street duty in between, FYI.
11/5/07 update. Video posted on YouTube http://www.youtube.com/watch?v=sx-zmGm3Kj4
Shot by a RX-7 tt two cars back
I totaled my Mazdaspeed3 at the track on 9/13. At the end of a long straight at a very high rate of speed, I hit the brakes and the pedal went to the floor. I pumped - nothing. I skidded off the track and hit a tire wall on the passenger side at somewhere between 100 - 110 mph. I am the luckiest guy I know. It has been three weeks now and I am mostly good to go. The car is toast.
No - my insurance is not going to pay. I will be parting it out and will post when and where in this thread.
Why did the brakes fail? Because I made an assumption.
I did not check the thickness of the inner pad and I ran out of pad! I assumed there was as much on the inner pad as the 1/3 -1/2 thickness I saw on the outer pad. Not.
Then something else happened - Under heavy braking, from what I have learned from talking to auto engineer types, this ABS system sensed braking on the LF wheel and not on the padless RF wheel, thought it was on ice, then dumped brake pressure in an attempt to drop down to braking threshold friction levels on ice. Every time I pumped the brakes, the same thing happened.....Crash! Skeptics should google "ABS dump mode" and do some reading before flaming. It was not brake fade or boiled fluid - BTDT.
So at this point it looks like my mistake caused the problem initially, and Mazda's design of the ABS ice software routine made it catastrophic. Bad combo.
Morals:
1. Never assume because you examined the pad thickness of the outside pad that you know the thickness of both pads! Check them both.
2. Never let your front pads get close to the backing plate on this car.
3. Never drive on the track more than you can afford to walk away from.
4. This car has a problem with ABS programming that showed up in a bad way on the track - be warned!
5. Brake pads for this car should have either wear indicators or sensors, given the consequences of running out of pad. They come with neither.
One last word - this car did a hell of a good job protecting me in the crash. Another last word - this thing kicks ass on the track. I highly recommend MS coilovers, Nitto NT-01 225/45 17 on 17 lb. 2006+ MX-5 wheels, MS CAI and Hawk HP+ pads, as long as you check pad wear closely. Mine lasted 3.5 track days plus street duty in between, FYI.
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