Wow... glad to hear you're OK. Too bad you weren't on an oval race track... could have put the car in neutral and rolled to a stop. I do hope it was an isolated incident or we may hear of more such cases. Once again I am thankful that you and your passenger made it out safely. Wise move to hit the bank sideways...
Brake failure results in totaled Viper
- Thread starter jpa99acr
- Start date
DEVILDOG
VCA Member North TX
Glad you are O.K.. Obviously, you're driving skill saved you. I'm very disapointed to hear that the PVO folks have not returned your contact. Very, very unprofessional and does not reflect a true commitment to us loyal VCA and VIPER owners. Maybe PVO was too busy getting Jay Leno's black SRT to him before they are officially available to everyone else that has a cert.. Nice to know all of us Viper and VCA members are treated equally! I'm sure that if your experience had happened to Jay Leno they would not have returned his calls either! Thanks for sharing your experience. Maybe you should replace your Viper with a FORD GT? BTW, I'm even more glad now that I don't have ABS and upgraded my brakes with StopTech.
ACR Larry
Enthusiast
Maybe John Dearing will post a reply here. I have seen his ABS brakes fail a couple time on the track with his 2001 GTS. Both times he was able to avoid any major damage, and I believe he has StopTecch on now. John?
Fred(DrivingSchool)Kinder
Enthusiast
Most important everyone walked away. Likely excessive temperature from the day of track activity and demo laps. Example, the ABS sensors may have been cooked from excessive hear. More aggressive brake pads generate more heat.
If no clear failure was definable it would be irresponsible for DC to speculate.
Contact Dan Cragin and or Bob Woodhouse and ask them. Dan works on many Vipers that are tracked and may be able to put a little more light on the subject.
I lost my pedal going into turn 2 at Laguna Seca in a 97GTS, it had Motul brake fluid, Dunlop Slicks and Porsche air deflectors and Porterfield race pads. I was running in to run groups which I assumed was to much heat for the brake fluid.
Also a major factor was my excessive braking due to lack of driving skill. I know guys who are really good drivers(Rich Bontempi), that do not have the same problem under the same conditions.
Bottom line is energy management within system limitations!
If no clear failure was definable it would be irresponsible for DC to speculate.
Contact Dan Cragin and or Bob Woodhouse and ask them. Dan works on many Vipers that are tracked and may be able to put a little more light on the subject.
I lost my pedal going into turn 2 at Laguna Seca in a 97GTS, it had Motul brake fluid, Dunlop Slicks and Porsche air deflectors and Porterfield race pads. I was running in to run groups which I assumed was to much heat for the brake fluid.
Also a major factor was my excessive braking due to lack of driving skill. I know guys who are really good drivers(Rich Bontempi), that do not have the same problem under the same conditions.
Bottom line is energy management within system limitations!
luc
Enthusiast
Fred,
saying that the faillure was likely due to excessive brake temperature and that the driver need to deal with the system (brake) limitation, is crazy.
The Viper is a car that have a top speed of 180mph + and the brakes SHOULD be designed to cope with the tremendous heat that go with repeated braking from those speeds.
A friend of mine have a M5 that he open track on a regular basis and with STOCK brakes and pads,he never had any "heat related" problems.
As for Turn 2 at LS,it is true that LS is very ******* brakes but any REAL sport car should have no problem with it.
On a car that go 180 +,you don't put tires that are only rated for 149,same thing for the brakes,all the people that I know that race/open track thir Vipers,complain about the brakes.
Luc 00GTS
03 SRT
69 Mustang race car
65 Shelby race car
1991 Roush T/A Mustang
SCCA National Competition Licence. (don't need you usual comment about driver school)
saying that the faillure was likely due to excessive brake temperature and that the driver need to deal with the system (brake) limitation, is crazy.
The Viper is a car that have a top speed of 180mph + and the brakes SHOULD be designed to cope with the tremendous heat that go with repeated braking from those speeds.
A friend of mine have a M5 that he open track on a regular basis and with STOCK brakes and pads,he never had any "heat related" problems.
As for Turn 2 at LS,it is true that LS is very ******* brakes but any REAL sport car should have no problem with it.
On a car that go 180 +,you don't put tires that are only rated for 149,same thing for the brakes,all the people that I know that race/open track thir Vipers,complain about the brakes.
Luc 00GTS
03 SRT
69 Mustang race car
65 Shelby race car
1991 Roush T/A Mustang
SCCA National Competition Licence. (don't need you usual comment about driver school)
Hoosier Daddy
Enthusiast
I believe a similar situation happened to a guy from the Carolina's Sam? He claimed his brake pedal went to the floor also and I believe he had a 2001. So this really isn't an isolated occurrence. Glad everything worked out well.
Vic
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Fred- Sensors could cause various malfunctions, true.
As far as the pedal sticking to the floor?
Maybe the master cylinder seal went south, allowing the pedal to travel to the floor, and the extra movement allowed the pedal to travel further than ever before.
You know, the master cylinder piston only travels just "so far" into the master cylinder cavity, before the fluid restricts its travel. So it kind of hones a smooth wear surface for itself. If the piston goes farther forward than that point, such as in the case of master cylinder piston seal failure, the piston now travels into, or near, the end of the cylinder, where it does not usually traverse. Brake cylinders can get pitted, corroded, or just plain yucky and sticky, in areas that the piston does not move through.
So my conclusion is, that the master cylinder piston seal failed, allowing the pedal to go to the floor. Once the pedal went to the floor, the master cylinder piston got stuck in the dirty or corroded area near the end of the master cylinder, which prevented the pedal from returning. Even if a car has ABS, it still has a master cylinder attached to the brake pedal, and the master cylinder is still prone to the effects decribed above. All the ABS system does, to my knowledge, is administer the application of the pressure to the wheels, depending on the wheel sensor feedback.
And if the sensors fail, the system either would not apply any pressure to the slave cylinders, or apply it irregularly. But even a sensor failure, to my knowledge, (as limited as it is), cannot cause the brake pedal to go to the floor. When the pedal goes to the floor, it displaces a certain volume of brake fluid. As far as I know, auto ABS systems have no way to acept that volume of fluid, except to apply it to the slave cylinders, which was not the case here. If the pedal goes to the floor, there is either a leak somewhere in the system, or the master cylinder DID NOT DISPLACE ANY FLUID, as in the case of master cylinder seal failure.
Here's why I don't feel entirely comfortable with the corroded master cylinder failure theory-
My knowledge of brake systems ends before the ABS era began, and I'm not sure if the ABS unit still somehow might have had something to do with the failure.
Also, its a little hard to belive that a 2001 car could already have a corroded master cylinder. But it could happen, or maybe there was some junk in the fluid.
If it was cylinder failure due to corrosion or debris, DC owes no apology. (Although their consultant could have spotted it with a post mortem brake-ectomy) I wonder if the ABS system is releasing debris into the fluid?
But you would think they would like to know! And maybe return the guys calls.
As far as the pedal sticking to the floor?
Maybe the master cylinder seal went south, allowing the pedal to travel to the floor, and the extra movement allowed the pedal to travel further than ever before.
You know, the master cylinder piston only travels just "so far" into the master cylinder cavity, before the fluid restricts its travel. So it kind of hones a smooth wear surface for itself. If the piston goes farther forward than that point, such as in the case of master cylinder piston seal failure, the piston now travels into, or near, the end of the cylinder, where it does not usually traverse. Brake cylinders can get pitted, corroded, or just plain yucky and sticky, in areas that the piston does not move through.
So my conclusion is, that the master cylinder piston seal failed, allowing the pedal to go to the floor. Once the pedal went to the floor, the master cylinder piston got stuck in the dirty or corroded area near the end of the master cylinder, which prevented the pedal from returning. Even if a car has ABS, it still has a master cylinder attached to the brake pedal, and the master cylinder is still prone to the effects decribed above. All the ABS system does, to my knowledge, is administer the application of the pressure to the wheels, depending on the wheel sensor feedback.
And if the sensors fail, the system either would not apply any pressure to the slave cylinders, or apply it irregularly. But even a sensor failure, to my knowledge, (as limited as it is), cannot cause the brake pedal to go to the floor. When the pedal goes to the floor, it displaces a certain volume of brake fluid. As far as I know, auto ABS systems have no way to acept that volume of fluid, except to apply it to the slave cylinders, which was not the case here. If the pedal goes to the floor, there is either a leak somewhere in the system, or the master cylinder DID NOT DISPLACE ANY FLUID, as in the case of master cylinder seal failure.
Here's why I don't feel entirely comfortable with the corroded master cylinder failure theory-
My knowledge of brake systems ends before the ABS era began, and I'm not sure if the ABS unit still somehow might have had something to do with the failure.
Also, its a little hard to belive that a 2001 car could already have a corroded master cylinder. But it could happen, or maybe there was some junk in the fluid.
If it was cylinder failure due to corrosion or debris, DC owes no apology. (Although their consultant could have spotted it with a post mortem brake-ectomy) I wonder if the ABS system is releasing debris into the fluid?
But you would think they would like to know! And maybe return the guys calls.
Vic
VCA Venom Member
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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by luc:
all the people that I know that race/open track thir Vipers,complain about the brakes.
<HR></BLOCKQUOTE>
But they also complain about their wives, lap times, weather, traffic, etc!
Ha-ha, just kidding! You've got good points.
all the people that I know that race/open track thir Vipers,complain about the brakes.
<HR></BLOCKQUOTE>
But they also complain about their wives, lap times, weather, traffic, etc!
Ha-ha, just kidding! You've got good points.
Fred(DrivingSchool)Kinder
Enthusiast
Luc, You opinion is yours.
I tend to take a little more ownership for my actions.
It would be nice to know the failure mechanism, as well as all the related details, like the boiling point of the brake fluid and specific condition of all the other components that survived.
I would guess 90% of Viper owners could not make the brakes fade at Laguna or at any track. And only a very few drivers can make the stock set-up fade at Laguna or any track. There is more than enough coverage about the Viper brakes. Good luck to the "Darwin Winner" that drives a Viper on the street to the point of brake fade!
That said I love my 4 corner 14" Stoptech's and the SRT10 is simply fantastic. I think is is called progress.
I tend to take a little more ownership for my actions.
It would be nice to know the failure mechanism, as well as all the related details, like the boiling point of the brake fluid and specific condition of all the other components that survived.
I would guess 90% of Viper owners could not make the brakes fade at Laguna or at any track. And only a very few drivers can make the stock set-up fade at Laguna or any track. There is more than enough coverage about the Viper brakes. Good luck to the "Darwin Winner" that drives a Viper on the street to the point of brake fade!
That said I love my 4 corner 14" Stoptech's and the SRT10 is simply fantastic. I think is is called progress.
GTS Dean
Enthusiast
Thanks for posting your experiences, and thank God you are safe. I seem to remember some gipes that PMUM had about the wheel speed pickup wiring melting on his (then) new 01 ACR. Never heard anything else about it, but he now runs a 4-wheel StopTech system on the car.
On many, many occasions, I've generated some brake temps well in excess of 1100F on the rotors and pads of my car and have not experienced any problems like this. I run Brake Man 3 or 4 pads, Porsche deflectors, stainless/teflon lines and AP 600 fluid with OE calipers, seals and master cylinder.
One problem I have found is that being stuck behind slower traffic during DE weekends will compromise cooling time in between brake applications. I frequently end up braking more often and for longer periods in "no passing zones" and it can lead to a long pedal because of heat soak. This also happens at Viper Days when you're stuck behind someone with big straight line power (read: a big wallet and inablitly to process info from the rearview mirror) but poor driving abilities in braking zones and corners.
On many, many occasions, I've generated some brake temps well in excess of 1100F on the rotors and pads of my car and have not experienced any problems like this. I run Brake Man 3 or 4 pads, Porsche deflectors, stainless/teflon lines and AP 600 fluid with OE calipers, seals and master cylinder.
One problem I have found is that being stuck behind slower traffic during DE weekends will compromise cooling time in between brake applications. I frequently end up braking more often and for longer periods in "no passing zones" and it can lead to a long pedal because of heat soak. This also happens at Viper Days when you're stuck behind someone with big straight line power (read: a big wallet and inablitly to process info from the rearview mirror) but poor driving abilities in braking zones and corners.
Herman Buehrle
Enthusiast
WHO did the work of changing the brake fluid, etc? Perhaps there was a petroleum based contamination of the parts somewhere during cleaning or installation? petroleum based stuff and the rubber used in brake systems is asking for failure....
jimandela
Enthusiast
Hoosier Daddy,
i had the same thought.. didnt this happen to Sam Kelly?
Scary.
Glad everyone walked away.
JIM
i had the same thought.. didnt this happen to Sam Kelly?
Scary.
Glad everyone walked away.
JIM
Fred(DrivingSchool)Kinder
Enthusiast
Sounds like the ABS had a stupid moment. Can you buy the car from your ins company? You could likely sell it for much more to a parts supplier and have the brake components for failure analysis. I still go with a heat related root cause. I know very little about the ABS system but I did see one, on a 2000 Vette, that went stupid, pedal to the floor as reported by the owner, a Viper Tech confirmed the same symptom. This was at Buttonwillow this summer. May be unrelated as the ABS systems may be different?
Good luck finding the failure. May help improve track driving safety for others.
Good luck finding the failure. May help improve track driving safety for others.
Tusc
Enthusiast
#1 - everyone walked away ok, thank God
#2 - WHO is your insurance carrier? And how did you explain the wreck to them? I've seen a few street car (read - race cars that are registered cars for the street) wrecks at LRP and have never heard of an insurance company that will cover a car that someone has slammed while racing. What kind of coverage did you have?
Wow, I have a short clip in my video folder on the pc of a red (presumably Skip Barber?) GTS with driver and instructor where the car is going into a corner in 4th and the brakes fail. Not sure how they went in this case - all I did was DL the video - but they went right into the tires and wrecked that one.
It sounds like a somewhat rare problem, but with so few Vipers on the road it becomes a more significant statistic.
Glad everyone is ok and you're getting a new car out of the deal!
#2 - WHO is your insurance carrier? And how did you explain the wreck to them? I've seen a few street car (read - race cars that are registered cars for the street) wrecks at LRP and have never heard of an insurance company that will cover a car that someone has slammed while racing. What kind of coverage did you have?
Wow, I have a short clip in my video folder on the pc of a red (presumably Skip Barber?) GTS with driver and instructor where the car is going into a corner in 4th and the brakes fail. Not sure how they went in this case - all I did was DL the video - but they went right into the tires and wrecked that one.
It sounds like a somewhat rare problem, but with so few Vipers on the road it becomes a more significant statistic.
Glad everyone is ok and you're getting a new car out of the deal!
Vic
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Well, this is alarming, and it worries me. I don't wanna meet the same fate....
And why did DC change the ABS system from model year 2001 to 2002? What exactly did they change? I have heard it was just a part number change, but that sounds like a thinly veiled shell game to avoid bringing any attention to a possible inherent defect that would result in a costly recall.
Also- If they admit there is a defect, it could set a precedent for lawsuits. To admit to it, it shows they have foreknowledge, and if they don't do anything, it shows negligence. (Thats why they don't return your calls, they try to avoid the issue entirely, and thusly allow themselves room to "credibly" claim that they knew nothing).
And so to avoid looking like they know anything about any defect in the ABS unit, they change the ABS system for 2002, and just call it a part number change. Far fetched? Ha! It happens all the time...
DC, you better step in right now, and answer the VCA as to why
Come clean, answer up to your customers. We will respect honesty, but avoiding the issue will compound feelings of obfuscation and evasion. Do the right thing, and makes us proud to be Dodge customers.
And why did DC change the ABS system from model year 2001 to 2002? What exactly did they change? I have heard it was just a part number change, but that sounds like a thinly veiled shell game to avoid bringing any attention to a possible inherent defect that would result in a costly recall.
Also- If they admit there is a defect, it could set a precedent for lawsuits. To admit to it, it shows they have foreknowledge, and if they don't do anything, it shows negligence. (Thats why they don't return your calls, they try to avoid the issue entirely, and thusly allow themselves room to "credibly" claim that they knew nothing).
And so to avoid looking like they know anything about any defect in the ABS unit, they change the ABS system for 2002, and just call it a part number change. Far fetched? Ha! It happens all the time...
DC, you better step in right now, and answer the VCA as to why
<LI>You don't return his calls
<LI>Why the ABS system was changed for 2002
<LI>Why your contracted investigator couldn't determine why his brake pedal stuck to the floor
Come clean, answer up to your customers. We will respect honesty, but avoiding the issue will compound feelings of obfuscation and evasion. Do the right thing, and makes us proud to be Dodge customers.
Vic
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Brett, for some reason, I think you are referring to the video of Sam, (?) whose passenger told him to turn it off right away, after the crash, yes? That car had the stock brakes altered, and after market braking system components installed that has a questionable record, at least according to some people on this board. But I have no first hand info on that. I just wanted to let you know that those were'nt stock brakes.
My understanding is that if you go to a driving school, as long as you are not doing timed laps, then its not "racing", and most or at least some insurance covers driving schools.
What I would like to know, is how an ABS system can allow the pedal to go to the floor. Its not like the pedal just puts an input into the computer! The pedal is pushing brake fluid into the ABS module. There is an actual amount of fluid displaced! If the module goes "stupid", or malfunctions in any way, that displaced fluid still has to go somewhere. It just doesn't get swallowed up by a big mysterious computer. When the pedal goes to the floor, the master cylinder either isn't displacing any fluid at all, or there is a leak somewhere.
Doesn't matter what the computerr is doing, or not doing! Volume is volume. Pascal's laws still apply. Either the master fluid did not displace any fluid, or there is a leak.
If the computer took the input from the pedal directly, and this input was subject to the viscisitudes of computer failure, then an electrical failure like a blown fuse or a weak battery/charging system would result in a loss of brakes. The world is not built this way. I'm almost 100% sure that ABS systems are designed "fail-safe", where if there is any electrical or electronic problem, the displaced brake fluid merely passes through the ABS module, to the slave cylinders.
And if I am wrong, and it doesn't work this way, then where does the displaced brake fluid go, when the pedal goes to the floor? Into the ABS modules' displaced brake fluid storage balloon? No such thing!
Which leads me back to my point- which is-
Either the master cylinder did not displace any fluid, or there is a leak somewhere.
But I still could be wrong.
Is there anyone out there who has a nuts and bolts knowledge of how ABS systems are designed? I don't mean just superficial knowledge, like its a closed loop real time sensor feedback pressure modulation device, or you puch the pedal, and it does magic, or some other off the cuff stuff. I mean, is there anyone out there who knows exactly what takes place inside the ABS module?
My guess is that it just pulses the pressure to the slave cylinders, according to the compared data from the sensors, relating it to vehicle speed, and determining which slave cylinder(s) to pulse, by how hard, and how fast, in real time.
So if I am right, and its just modulating the pressure to the slave cylinders, then there is still no reason the computer could just "get stupid", and let the pedal go to the floor. Its a sealed system, and that volume has to go somewhere, even if the computer malfunctions.
I could see how a computerr malfunction coul dprevent any pressure from reaching the slaves, or pulse them erractically, but this would be a solid pedal, but no stopping action kind of a symtom. This still does not relate to the pedal going to the floor. I would have to conclude that something essentially mechanical in nature faiilure took place, such as when the master cylinder seal lets the fluid go by the piston, or if there is an outright leak somewhere.
But what about dual-piston master cylinders? Do our Vipers have dual pistons?
And is there anything I am missing, concerning the nature of ABS modules? I'll admit I never took one apart, or studied them.
Anybody out there got anything solidly technical to add? I'm at the end of my understanding....
My understanding is that if you go to a driving school, as long as you are not doing timed laps, then its not "racing", and most or at least some insurance covers driving schools.
What I would like to know, is how an ABS system can allow the pedal to go to the floor. Its not like the pedal just puts an input into the computer! The pedal is pushing brake fluid into the ABS module. There is an actual amount of fluid displaced! If the module goes "stupid", or malfunctions in any way, that displaced fluid still has to go somewhere. It just doesn't get swallowed up by a big mysterious computer. When the pedal goes to the floor, the master cylinder either isn't displacing any fluid at all, or there is a leak somewhere.
Doesn't matter what the computerr is doing, or not doing! Volume is volume. Pascal's laws still apply. Either the master fluid did not displace any fluid, or there is a leak.
If the computer took the input from the pedal directly, and this input was subject to the viscisitudes of computer failure, then an electrical failure like a blown fuse or a weak battery/charging system would result in a loss of brakes. The world is not built this way. I'm almost 100% sure that ABS systems are designed "fail-safe", where if there is any electrical or electronic problem, the displaced brake fluid merely passes through the ABS module, to the slave cylinders.
And if I am wrong, and it doesn't work this way, then where does the displaced brake fluid go, when the pedal goes to the floor? Into the ABS modules' displaced brake fluid storage balloon? No such thing!
Which leads me back to my point- which is-
Either the master cylinder did not displace any fluid, or there is a leak somewhere.
But I still could be wrong.
Is there anyone out there who has a nuts and bolts knowledge of how ABS systems are designed? I don't mean just superficial knowledge, like its a closed loop real time sensor feedback pressure modulation device, or you puch the pedal, and it does magic, or some other off the cuff stuff. I mean, is there anyone out there who knows exactly what takes place inside the ABS module?
My guess is that it just pulses the pressure to the slave cylinders, according to the compared data from the sensors, relating it to vehicle speed, and determining which slave cylinder(s) to pulse, by how hard, and how fast, in real time.
So if I am right, and its just modulating the pressure to the slave cylinders, then there is still no reason the computer could just "get stupid", and let the pedal go to the floor. Its a sealed system, and that volume has to go somewhere, even if the computer malfunctions.
I could see how a computerr malfunction coul dprevent any pressure from reaching the slaves, or pulse them erractically, but this would be a solid pedal, but no stopping action kind of a symtom. This still does not relate to the pedal going to the floor. I would have to conclude that something essentially mechanical in nature faiilure took place, such as when the master cylinder seal lets the fluid go by the piston, or if there is an outright leak somewhere.
But what about dual-piston master cylinders? Do our Vipers have dual pistons?
And is there anything I am missing, concerning the nature of ABS modules? I'll admit I never took one apart, or studied them.
Anybody out there got anything solidly technical to add? I'm at the end of my understanding....
DEVILDOG
VCA Member North TX
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Vic:
Brett, for some reason, I think you are referring to the video of Sam, (?) whose passenger told him to turn it off right away, after the crash, yes? That car had the stock brakes altered, and after market braking system components installed that has a questionable record, at least according to some people on this board. But I have no first hand info on that. I just wanted to let you know that those were'nt stock brakes.
My understanding is that if you go to a driving school, as long as you are not doing timed laps, then its not "racing", and most or at least some insurance covers driving schools.
What I would like to know, is how an ABS system can allow the pedal to go to the floor. Its not like the pedal just puts an input into the computer! The pedal is pushing brake fluid into the ABS module. There is an actual amount of fluid displaced! If the module goes "stupid", or malfunctions in any way, that displaced fluid still has to go somewhere. It just doesn't get swallowed up by a big mysterious computer. When the pedal goes to the floor, the master cylinder either isn't displacing any fluid at all, or there is a leak somewhere.
Doesn't matter what the computerr is doing, or not doing! Volume is volume. Pascal's laws still apply. Either the master fluid did not displace any fluid, or there is a leak.
If the computer took the input from the pedal directly, and this input was subject to the viscisitudes of computer failure, then an electrical failure like a blown fuse or a weak battery/charging system would result in a loss of brakes. The world is not built this way. I'm almost 100% sure that ABS systems are designed "fail-safe", where if there is any electrical or electronic problem, the displaced brake fluid merely passes through the ABS module, to the slave cylinders.
And if I am wrong, and it doesn't work this way, then where does the displaced brake fluid go, when the pedal goes to the floor? Into the ABS modules' displaced brake fluid storage balloon? No such thing!
Which leads me back to my point- which is-
Either the master cylinder did not displace any fluid, or there is a leak somewhere.
But I still could be wrong.
Is there anyone out there who has a nuts and bolts knowledge of how ABS systems are designed? I don't mean just superficial knowledge, like its a closed loop real time sensor feedback pressure modulation device, or you puch the pedal, and it does magic, or some other off the cuff stuff. I mean, is there anyone out there who knows exactly what takes place inside the ABS module?
My guess is that it just pulses the pressure to the slave cylinders, according to the compared data from the sensors, relating it to vehicle speed, and determining which slave cylinder(s) to pulse, by how hard, and how fast, in real time.
So if I am right, and its just modulating the pressure to the slave cylinders, then there is still no reason the computer could just "get stupid", and let the pedal go to the floor. Its a sealed system, and that volume has to go somewhere, even if the computer malfunctions.
I could see how a computerr malfunction coul dprevent any pressure from reaching the slaves, or pulse them erractically, but this would be a solid pedal, but no stopping action kind of a symtom. This still does not relate to the pedal going to the floor. I would have to conclude that something essentially mechanical in nature faiilure took place, such as when the master cylinder seal lets the fluid go by the piston, or if there is an outright leak somewhere.
But what about dual-piston master cylinders? Do our Vipers have dual pistons?
And is there anything I am missing, concerning the nature of ABS modules? I'll admit I never took one apart, or studied them.
Anybody out there got anything solidly technical to add? I'm at the end of my understanding....
<HR></BLOCKQUOTE>
YES there is somebody out there that knows the answer to these questions...DCX and specifically PVO if they would return the calls! Very distrubing that the DCX contracted inspector comes up with a conclusion that he dosen't know what happened. What's with that? Are brake and ABS systems a black art instead of science? Sounds like rear end covering to me. Also, comments about DCX making progress on the brakes of the SRT does not eliminate the responsibility of DCX and PVO to respond to this important safety issue concerning current GEN Vipers and having the courtesy and concern to respond to viper1997. Maybe we could get Jay Leno to call them to get an answer?
Brett, for some reason, I think you are referring to the video of Sam, (?) whose passenger told him to turn it off right away, after the crash, yes? That car had the stock brakes altered, and after market braking system components installed that has a questionable record, at least according to some people on this board. But I have no first hand info on that. I just wanted to let you know that those were'nt stock brakes.
My understanding is that if you go to a driving school, as long as you are not doing timed laps, then its not "racing", and most or at least some insurance covers driving schools.
What I would like to know, is how an ABS system can allow the pedal to go to the floor. Its not like the pedal just puts an input into the computer! The pedal is pushing brake fluid into the ABS module. There is an actual amount of fluid displaced! If the module goes "stupid", or malfunctions in any way, that displaced fluid still has to go somewhere. It just doesn't get swallowed up by a big mysterious computer. When the pedal goes to the floor, the master cylinder either isn't displacing any fluid at all, or there is a leak somewhere.
Doesn't matter what the computerr is doing, or not doing! Volume is volume. Pascal's laws still apply. Either the master fluid did not displace any fluid, or there is a leak.
If the computer took the input from the pedal directly, and this input was subject to the viscisitudes of computer failure, then an electrical failure like a blown fuse or a weak battery/charging system would result in a loss of brakes. The world is not built this way. I'm almost 100% sure that ABS systems are designed "fail-safe", where if there is any electrical or electronic problem, the displaced brake fluid merely passes through the ABS module, to the slave cylinders.
And if I am wrong, and it doesn't work this way, then where does the displaced brake fluid go, when the pedal goes to the floor? Into the ABS modules' displaced brake fluid storage balloon? No such thing!
Which leads me back to my point- which is-
Either the master cylinder did not displace any fluid, or there is a leak somewhere.
But I still could be wrong.
Is there anyone out there who has a nuts and bolts knowledge of how ABS systems are designed? I don't mean just superficial knowledge, like its a closed loop real time sensor feedback pressure modulation device, or you puch the pedal, and it does magic, or some other off the cuff stuff. I mean, is there anyone out there who knows exactly what takes place inside the ABS module?
My guess is that it just pulses the pressure to the slave cylinders, according to the compared data from the sensors, relating it to vehicle speed, and determining which slave cylinder(s) to pulse, by how hard, and how fast, in real time.
So if I am right, and its just modulating the pressure to the slave cylinders, then there is still no reason the computer could just "get stupid", and let the pedal go to the floor. Its a sealed system, and that volume has to go somewhere, even if the computer malfunctions.
I could see how a computerr malfunction coul dprevent any pressure from reaching the slaves, or pulse them erractically, but this would be a solid pedal, but no stopping action kind of a symtom. This still does not relate to the pedal going to the floor. I would have to conclude that something essentially mechanical in nature faiilure took place, such as when the master cylinder seal lets the fluid go by the piston, or if there is an outright leak somewhere.
But what about dual-piston master cylinders? Do our Vipers have dual pistons?
And is there anything I am missing, concerning the nature of ABS modules? I'll admit I never took one apart, or studied them.
Anybody out there got anything solidly technical to add? I'm at the end of my understanding....
<HR></BLOCKQUOTE>
YES there is somebody out there that knows the answer to these questions...DCX and specifically PVO if they would return the calls! Very distrubing that the DCX contracted inspector comes up with a conclusion that he dosen't know what happened. What's with that? Are brake and ABS systems a black art instead of science? Sounds like rear end covering to me. Also, comments about DCX making progress on the brakes of the SRT does not eliminate the responsibility of DCX and PVO to respond to this important safety issue concerning current GEN Vipers and having the courtesy and concern to respond to viper1997. Maybe we could get Jay Leno to call them to get an answer?
jkracer9
Enthusiast
Contact Sam Kelly at [email protected] or [email protected] or find one of his old post about his problem that sounds like yours. He also totaled his 01 Viper. Did you have insurance that covered road racing or if it was a school did you buy their insurance?
Good Luck
Good Luck
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Vic:
.....Brett, for some reason, I think you are referring to the video of Sam, (?) whose passenger told him to turn it off right away, after the crash, yes? That car had the stock brakes altered, and after market braking system components installed that has a questionable record, at least according to some people on this board. But I have no first hand info on that. I just wanted to let you know that those were'nt stock brakes. .... <HR></BLOCKQUOTE>
Vic,
I was the passenger in that wreck last October. Took about 5 weeks for my cracked ribs to heal from hitting the center console while we were rolling. The brake setup on that car had either Alcon's or Brembos on the front (not sure what that tuner uses) and the stock fronts on the rear. The car was a '99 and did not have ABS.
Viper1997,
Glad you and your passenger were OK. We went straight in at almost the top of 4th gear, end over ended and rolled. Could have been a lot worse for all of us. Hope you get to the root of the cause.
Sean
<FONT COLOR="#ff0000" SIZE="1" FACE="Verdana, Arial">This message has been edited by Sean Roe on 12-01-2002 at 06:42 PM</font>
.....Brett, for some reason, I think you are referring to the video of Sam, (?) whose passenger told him to turn it off right away, after the crash, yes? That car had the stock brakes altered, and after market braking system components installed that has a questionable record, at least according to some people on this board. But I have no first hand info on that. I just wanted to let you know that those were'nt stock brakes. .... <HR></BLOCKQUOTE>
Vic,
I was the passenger in that wreck last October. Took about 5 weeks for my cracked ribs to heal from hitting the center console while we were rolling. The brake setup on that car had either Alcon's or Brembos on the front (not sure what that tuner uses) and the stock fronts on the rear. The car was a '99 and did not have ABS.
Viper1997,
Glad you and your passenger were OK. We went straight in at almost the top of 4th gear, end over ended and rolled. Could have been a lot worse for all of us. Hope you get to the root of the cause.
Sean
<FONT COLOR="#ff0000" SIZE="1" FACE="Verdana, Arial">This message has been edited by Sean Roe on 12-01-2002 at 06:42 PM</font>
lleone
Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Vic:
But what about dual-piston master cylinders? Do our Vipers have dual pistons?
<HR></BLOCKQUOTE>
At least the 2000s do. From the manual, it states that the system is vertically split, meaning that the front is on one system and the rear on a another. Normally this is diagonally split so that if you lose pressure in one system you still have one front and the opposite rear. With the Viper's system, if you loose the fronts, you'll only be braking on the rears - pretty scaring in my book.
Also from the manual, the diagnositic chart suggests that if the pedal goes to the floor with no brakes, the possible cause is the power brake booster runout, ie no vacuum. I'm not so sure about this though as I still like your thoughts on where the fluid went.
But what about dual-piston master cylinders? Do our Vipers have dual pistons?
<HR></BLOCKQUOTE>
At least the 2000s do. From the manual, it states that the system is vertically split, meaning that the front is on one system and the rear on a another. Normally this is diagonally split so that if you lose pressure in one system you still have one front and the opposite rear. With the Viper's system, if you loose the fronts, you'll only be braking on the rears - pretty scaring in my book.
Also from the manual, the diagnositic chart suggests that if the pedal goes to the floor with no brakes, the possible cause is the power brake booster runout, ie no vacuum. I'm not so sure about this though as I still like your thoughts on where the fluid went.
dancojax
Enthusiast
Somehow, I thought that ABS failure defaulted to 'normal' brakes.
How wrong am/was I in believing this?
How wrong am/was I in believing this?
DanElam
Enthusiast
Like you, I am an instructor at the track from time to time. At Kershaw, SC, I was once driving the Viper and lost the brakes. Kershaw is a tight, technical track with intense braking. The long and the short of it is that I boiled the brakes and very nearly whacked the car. My guess is that is what happened on your car. The brakes are the weakness of the car and extended track driving can really get the stock brakes hot.
Now I make sure that the Viper always has fresh Motul or something similar that can withstand the higher temperatures at the track.
Sorry to hear about your car. Glad you are ok!
Now I make sure that the Viper always has fresh Motul or something similar that can withstand the higher temperatures at the track.
Sorry to hear about your car. Glad you are ok!
GTS Bruce
Enthusiast
We used to have a Buick Lesabre.My wife wanted a comfortable car to drive her mother and aunts around in when they needed to go someplace.The brakes drove us nuts with pedal going to the floor,warning lights going on,abs faults lighting up.The problem occured less than once a month.There were no exterior hydraulic leaks,vacuum leaks,or electrical problems.Finally it turned out to be an intermittent internal leak in the master cylinder.Solved by replacing master cylinder and verified upon dissection.Could this be happening to our Vipers?
pdmracing
Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by lleone:
At least the 2000s do. From the manual, it states that the system is vertically split, meaning that the front is on one system and the rear on a another. Normally this is diagonally split so that if you lose pressure in one system you still have one front and the opposite rear. With the Viper's system, if you loose the fronts, you'll only be braking on the rears - pretty scaring in my book.
/B]<HR></BLOCKQUOTE>
The Brake system is split front to rear & not diagonal, the rears require a pressure differential to stop them from locking before the fronts do.This is standard operating procedure on most high performance cars. The anti lock system, if it fails, will not affect the action of the mechanical aspects of the braking system. The anti lock failure will not cause the brakes to fail.Many sanctioning bodies make us disconnect the anti lock feature.( by pulling the fuse or disconnecting the electrics in most cases.)
Now what happened? other than the obvious , the following has happened to me on two separate occasions on a brand "P" car, in fact it happened just this month, here goes:
I am at Carolina motorsports park, leading the race comfortably, the car is perfect, entering turn 1 , my pedal goes to the floor, in a panic I pump then & nothing, I manage to make it & by the next series of corners, the pedal is back, firm & hard, no pulling no fade? what gives, ......The spindle. The spindle came apart 3 or 4 laps later with bad results, but no one got hurt. At the same track this month, I had a similar occurrence, total brake failure then the pedal came back. This time a stub axle retainer in the rear end lossened.This time I had knew something bad was going to happen, so I avoided the big one.
Lets look @ my last incident. The Axle nut backed off, this allowed the brake disk to spread the caliper, when in effect the caliper was the only thing holding the hub & wheel on the car. The caliper spreading, allowed all the braking pressure to drop as that brake to tried to make up the space, think of letting the bleeder valve open at that wheel for an instant, the pedal goes to the floor & no brakes.
This example could of easily be caused by a failed wheel bearing, a cracked axle or spindle, or a host of other common & not so common causes. Other than the Master Cylinder or individual components failing, there isn't really much to the mechanical aspects of the braking system. The problem with diagnosing barking systems is that there are so many rubber parts & seals that when not under pressure , look & appear normal, they may not even leak or show any signs of damage when stationary. I have seen rubber brake lines blow up like balloons, & calipers spit fluid past their seals almost across the garage!
Unfortunately, due to the crash damage, you may never find the exact cause.
At least the 2000s do. From the manual, it states that the system is vertically split, meaning that the front is on one system and the rear on a another. Normally this is diagonally split so that if you lose pressure in one system you still have one front and the opposite rear. With the Viper's system, if you loose the fronts, you'll only be braking on the rears - pretty scaring in my book.
/B]<HR></BLOCKQUOTE>
The Brake system is split front to rear & not diagonal, the rears require a pressure differential to stop them from locking before the fronts do.This is standard operating procedure on most high performance cars. The anti lock system, if it fails, will not affect the action of the mechanical aspects of the braking system. The anti lock failure will not cause the brakes to fail.Many sanctioning bodies make us disconnect the anti lock feature.( by pulling the fuse or disconnecting the electrics in most cases.)
Now what happened? other than the obvious , the following has happened to me on two separate occasions on a brand "P" car, in fact it happened just this month, here goes:
I am at Carolina motorsports park, leading the race comfortably, the car is perfect, entering turn 1 , my pedal goes to the floor, in a panic I pump then & nothing, I manage to make it & by the next series of corners, the pedal is back, firm & hard, no pulling no fade? what gives, ......The spindle. The spindle came apart 3 or 4 laps later with bad results, but no one got hurt. At the same track this month, I had a similar occurrence, total brake failure then the pedal came back. This time a stub axle retainer in the rear end lossened.This time I had knew something bad was going to happen, so I avoided the big one.
Lets look @ my last incident. The Axle nut backed off, this allowed the brake disk to spread the caliper, when in effect the caliper was the only thing holding the hub & wheel on the car. The caliper spreading, allowed all the braking pressure to drop as that brake to tried to make up the space, think of letting the bleeder valve open at that wheel for an instant, the pedal goes to the floor & no brakes.
This example could of easily be caused by a failed wheel bearing, a cracked axle or spindle, or a host of other common & not so common causes. Other than the Master Cylinder or individual components failing, there isn't really much to the mechanical aspects of the braking system. The problem with diagnosing barking systems is that there are so many rubber parts & seals that when not under pressure , look & appear normal, they may not even leak or show any signs of damage when stationary. I have seen rubber brake lines blow up like balloons, & calipers spit fluid past their seals almost across the garage!
Unfortunately, due to the crash damage, you may never find the exact cause.
Sonny 00 GTS ACR
Enthusiast
Pete,
I don't know if you were referring to your Porsche or to your Viper regarding the hub problems, but many drivers in ViperDays including myself have had problems with hubs.
This past season some people I work with have developed a pre-ABS front replacement hub that is patterned after the type they use in NASCAR events and it has worked very well. They use roller bearing and the hubs can be inspected and repacked unlike the stock Viper part. The hubs run quite a bit cooler as well.
I'm not a mechanic myself, but would be happy to get more details for you if you are interested. Several drivers have had problems with broken spindles this past season and some ended up replacing the hubs after every couple of races just to be safe.
If you click on my Avatar you can see the front hub in the picture.
I don't know if you were referring to your Porsche or to your Viper regarding the hub problems, but many drivers in ViperDays including myself have had problems with hubs.
This past season some people I work with have developed a pre-ABS front replacement hub that is patterned after the type they use in NASCAR events and it has worked very well. They use roller bearing and the hubs can be inspected and repacked unlike the stock Viper part. The hubs run quite a bit cooler as well.
I'm not a mechanic myself, but would be happy to get more details for you if you are interested. Several drivers have had problems with broken spindles this past season and some ended up replacing the hubs after every couple of races just to be safe.
If you click on my Avatar you can see the front hub in the picture.
malcoll
Enthusiast
I used to own a Jaguar XJ-S... w/ABS. It gave me the strangest fits. Sometimes when I would apply the brakes... NOTHING... just a super hard pedal... and nothing to the calipers. Other times... it might just go to the floor, like in your case.
Turned out to be the ABS module.... it's solenoids would just not operate.. at least that was the explanation I was given.
I no longer own that car. Too scared to let my wife drive it.. so it is gone.
Lance
Turned out to be the ABS module.... it's solenoids would just not operate.. at least that was the explanation I was given.
I no longer own that car. Too scared to let my wife drive it.. so it is gone.
Lance
Tom and Vipers
Enthusiast
Any possibility of the adjustable pedal mechanism breaking or falling apart?
For the pedal to stay on the floor, the problem sounds like it would be upstream of the master cylinder which really leaves the brake pedal itself and its return spring.
For the pedal to stay on the floor, the problem sounds like it would be upstream of the master cylinder which really leaves the brake pedal itself and its return spring.
SoCal Craig
Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by ACR Larry:
Maybe John Dearing will post a reply here. I have seen his ABS brakes fail a couple time on the track with his 2001 GTS. Both times he was able to avoid any major damage, and I believe he has StopTecch on now. John?
<HR></BLOCKQUOTE>
John's car is an '02. Nevertheless, he did experience ABS problems, though I don't think he had the "pedal to the floor" problem described above. I believe he continued to have the ABS problems after installing StopTechs but has since had it solved and fixed.
But I have an '01 with stock brakes and Brakeman #3 pads. This stuff is beginning to scare me so I hope we can get to the bottom of it. I'd have to admit I've often thought about the brakes entering Turn #1 at Willow Springs. Doesn't help my confidence any hearing the above, with no answers from DA
. Will StopTechs help? Has anyone had a brake failure with StopTechs? If it's a master cylinder problem then I suppose even StopTech equipped cars are at danger.
Maybe John Dearing will post a reply here. I have seen his ABS brakes fail a couple time on the track with his 2001 GTS. Both times he was able to avoid any major damage, and I believe he has StopTecch on now. John?
<HR></BLOCKQUOTE>
John's car is an '02. Nevertheless, he did experience ABS problems, though I don't think he had the "pedal to the floor" problem described above. I believe he continued to have the ABS problems after installing StopTechs but has since had it solved and fixed.
But I have an '01 with stock brakes and Brakeman #3 pads. This stuff is beginning to scare me so I hope we can get to the bottom of it. I'd have to admit I've often thought about the brakes entering Turn #1 at Willow Springs. Doesn't help my confidence any hearing the above, with no answers from DA
lleone
Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by [email protected]:
Thanks for affirming the accuracy of the manual. Any thoughts of the booster aspect since it is in the diagnostic chart as a possible cause?
Lou
Thanks for affirming the accuracy of the manual. Any thoughts of the booster aspect since it is in the diagnostic chart as a possible cause?
Lou
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