Brake failure results in totaled Viper

[99t1]

just like Malcoll...at least 3 times during track driving of my 01 ACR I have experienced super hard pedal and NO Braking but only for a LOOOOOONNG second or so. A few higher ups on the technical ladder have attributed this state to "bump logic" where during extreme braking, bumpiness or some other "force" is upsetting the sensor(s) and causing the computer to crap out and thereby canceling all braking...but I do not recall ever feeling the ABS pulsing while this was happening or the pedal going soft.

As others have mentioned, when you get the fronts up @900-1100 degrees there is a good chance the sensors will misread or fry too. Hmmm..I wonder if there is something to this "part number" change.

I too was very disappointed that the good folks at PVO did not respond to any calls or emails pertaining to a few issues I have had with the car. I guess they really are all workin in shining up Leno's ride or drag racing more jet.

------
Above all I reserve the right to be wrong.


<FONT COLOR="#ff0000" SIZE="1" FACE="Verdana, Arial">This message has been edited by 99t1 on 11-30-2002 at 09:12 PM</font>

 

[Vic]

If the pedal will not return, it seems to me that the pedal is directly coupled to the master piston, in both directions of its travel. And since the pedal would not return, it seems likely that the piston got stuck in that dirty area forward of the piston's usual travel. So why did the pedal go to the floor?

Possibilities-

1. Debris in fluid, causing the master piston seal to fail. (No fluid displacement)?

2. Expanding brake lines? "Blowing up like balloons"?

3. Vapor in master cylinder, due to boiling fluid?

4. Leaks after master cylinder?

5. Clogged "by-pass port"?

Once my 1980 F250's pedal went to the floor. (No ABS). The shop said the master cylinder had a by-pass port, that got clogged. They flushed the system, and this seemed to be the answer.

So what does a by-pass port do? Let fluid that sneaks by the back side of the master piston back into the system? That would sound reasonable, because no seal is 100%. If fluid weeps past the master piston seal, it would get trapped behind the piston, and it would have to leak out somewhere, like into the vacuum assist plenum. So I guess a by-pass port is a one-way passage, that allows seal run-off to be admitted back into the system, when the brkae pedal is released.

If it has a by-pass port for this purpose, then it will have a check valve, that only allows the passage way, (or port), to be open only when the pedal is released. This valve may be held open by debris, and if it is stuck open, then the pedal could go to the floor. The fluid would just go around the piston, filling up the master cylinder on the back side of the piston when the pedal is pushed, and this fluid would return to the front side when the pedal is released. (Unless the piston gets stuck in the dirty un-traveled area near the end of the cylinder, forward of the pistons' usual travel). In which case the pedal would not return, assuming it is directly coupled to the master piston, in both directions of travel.

Another thought occured to me-

The sensors are reading a gear looking thingy, in the hub area. This gear makes the pulses read by the sensors, as it rotates and each "tooth" passes the sensor, causing the generation of pulses, read by the computer, and compared to vehicle speed, for servo actuation if needed. Both the gear and the sensor are exposed, and being magnetic, they can pick up ferrous materials from the road.

Last time I looked at a hub on mine, the sensor was covered with incidental metal shavings and debris.

If the sensors are reading the ferrous teeth, then they can also read ferrous debris! If the debris is not moving, like when the sensor is covered with magnetic material, then the sensor will not be reading pulses at all. It will instead just be in a static state of either on or off, but won't toggle, presumably. No pulses could be interpreted by the computer as a lack of wheel rotation, or as an outright sensor failure, if the software has any level of safety redundancy written in.

I'm not sure if the accumulated crap in that area can cause a malfunction, but it seems reasonable to clean it off periodically to avoid the possibility of the brakes from screwing up.

Anybody heard of accumulated ferrous debris affecting sensor or computer operation?

How 'bout a by-pass port? Our Vipers got that?

Maybe I'll have to write Herb Helbig, for publication in the next Viper Quarterly.

Question- Uh, Herb, why are brakes failing in the 2001 Vipers?

Answer- What do you mean? Brakes can fail on any car, in any model year. Next question?

 

[lleone]

I did a little more poking around. A loss of vacuum pressure to the power brake booster could have caused this. As mentioned above, it's unfortunate that with the accident, the exact cause in this case may never be determined.

It would be an interesting experiment to pull the vacuum line to the brake booster and test the pedal (with car not moving of course). I don't have time today, but maybe next weekend.

Any other thoughts?

 

[Vic]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by lleone:
I did a little more poking around. A loss of vacuum pressure to the power brake booster could have caused this. As mentioned above, it's unfortunate that with the accident, the exact cause in this case may never be determined.

It would be an interesting experiment to pull the vacuum line to the brake booster and test the pedal (with car not moving of course). I don't have time today, but maybe next weekend.

Any other thoughts?

<HR></BLOCKQUOTE>

Interesting.. I'll try that if I can, today.

 

[SAM Team]

viper1997 and Friends,

I have been reading this note for a couple of days now and thanks to a couple of good Viper friends who brought it to my attention. I have not been reading as much lately...

1. The 2002 w/ ABS Yellow Fever is in the Viper Den safe and warm and has about 2500 miles on it now. It has the Stop Tech System all the way around this was done at the 165 mile mark with many other mods including steel brake lines.

2. My Red 99 Venom 600 ACR non ABS is in the junk yard waiting on the insurance to finish whatever it is they do, get someone else to pay mostly. They did pay me for my loss of the car. We just passed the anniversary date on October 26th. Brembos on the front, fronts moved to the back, portioning valve installed, brake air duct cooling system installed, steel brake lines. Master Cylinder was still stock.

3. There are so many things that viper1997 said that are almost identical it makes my skin crawl. Temperature outside 55, car running cool, 4 or 5 laps on track, toward the end of the day, Motul 600 we never put more than 100 miles before we flush completely, car is running perfect we are fixing to load up and head to Tulsa for the Viper Day Finals, we were ready to compete. Sean had me ready and we had decided not to stay the weekend with BMW Club even though we had paid for the entire weekend. My Viper was maintained very closely not as good as the McCanns or Sonny's but pretty close.

4. I hear a lot about brakes getting hot, boiling brake fluid, spongy pedals.... The only way I know how to explain it is get on your local track head down the front straight or back as fast as you can go and when you enter the braking zone, do not move your foot, ok go ahead and press the clutch maybe that will take a little of the speed off and then hang on for this is what we are talking about, it is like you have pressed nothing. I really do not think most of you are understanding what is going on here. Just try to imagine this in your mind, hopefully no one is in front of you stopped on the track. Try it at 70 mph in a tight 90 degree "or more" corner and see if you can rub some speed off once you are in the braking zone.

5. Guys all I know is it happened and it not suppose to. I wish I had made a mistake but I didn't. At minimum we should have had at least half of the brakes, front, rear, diagonal, we had nothing...the last corner I just came out of I did not even down shift I used the brakes and they were working fine. After going down the entire front stretch (CMP-Kershaw) and touching them with my right toe nothing, no pressure, nothing. To be honest I can not remember if the pedal came back to me in my mind I was pumping it, I remember it hitting bottom, but I was out of time and my mind was on downshifting, or trying to slide the car and that did not even work. The slicks would not bite because I could not get the nose down. In hind sight the best thing happened we went in head first and the front of the Viper absorbed all the force.

I have no ax to grind with anyone. If this is a fluke then it is a fluke. I just do not want it to happen to one of you. My wife has lived through this ordeal, she went to Nashville with me and had one of the greatest times of her life. I "will not" share viper1997 or your nor mine notes with her.....this will only trouble her more. She wants her on Viper now! I am afraid this will discourage her.

By most all accounts Sean and I should have not lived through this accident it was bad...the good Lord chose to leave both of us here. I will be forever thankful for the things He has allowed me to accomplish over the last year. When I got into the Viper that day I knew where I stood with the Lord and I knew when I got out my life would never be the same. I know the Lord did not cause this accident but I do know he saved our lives.

I guess we will wait to see if there is a next occurrence....I hope there is not one....are there others already out there...if so fix the problem!

Your Brother In Christ,
Sam

"You must first Give in order to Receive"

 

[jcaspar1]

Do you think bleeding techniques could have anything to do with the problems? If one uses speed bleeders or the old two person pump method the master cylinder pistion will travel much further than in normal use which could result in seal damage if a ridge develops in the master cylinder bore.

Just a thought...

 

[pdmracing]

Originally posted by Sonny 00 GTS ACR:
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.

Sonny it was my Porsche that had the problems, but now knowing that the ABS cars are having spindle issues, I think this could very well explain the problem.

 

[pdmracing]

I think bleeding tech. may cause a problem, but this was catostophic failure, I would concentrate on the master cylinder malfunctioning, or some other mechanical breakdown like the front spindle/bearing/caliper/rotor coming apart.

 

[SoCal Craig]

SAM, thanks for explaining your most unfortunate experience. I'm sure it must be hard to recall those horrible memories. I had heard "through the grapevine" about your accident with Sean but did not know the details. I really appreciate your thoughts on this matter in our effort to get a better understanding of what is actually happening to our Vipers. God bless you, your wife and Sean.

VIC, I nominate you to find out what is wrong with our '01's

. Seems like you have a good understaning of hydraulic systems being in the elevator business

. Either that or the elevator business is slow

.

Until then I think I'll track my other two cars and keep the Viper on the street

.

 

[jimandela]

I would like to hear from DC on this.
Maybe Joe or Tony can take this to the powers that be.
This should be checked out.
When I told my Dad about Sam's incident he was concerned.
I told him relax fluke. But now a second time... possible problem.
He flipped. extremely concerned.

So to put mine and my parents mind at easy... please investigate this issue.

JIM

 

[Vic]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by SoCal Craig:

VIC, I nominate you to find out what is wrong with our '01's

.
<HR></BLOCKQUOTE>

Wish I had the time and knowledge!

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
Either that or the elevator business is slow

.
<HR></BLOCKQUOTE>

Well, you know, its "up and down"!


Ha! I've been waiting a long time to say that! Usually I have to hear it from people who think they are funny. This time i get to use it myself. Ha! That feels guuuuuuud.

Thanks for the set-up!

 

[jimandela]

mjguflaw has a point.
Do I think DC is purposely hiding something..NO!
but I think this should be checked out.

mjguflaw's post reminds of Michael Douglas in the movie Wall Street where he says "greed is good"
I am sure that those type of recall conversations DO happen.
They have to happen it is called business.

To make me happy:
I would like to read a post in the next few days that says from team viper or pvo (whatever the new name is) that says " we checked out the brakes of the viper we think this might have
happened because.... please check this or do that or do nothing."

But some piece of info would be helpful.
JIM

 

[mjguflaw]

Anyone else reminded of the scene in Fight Club with Ed Norton and the businesswoman on the plane?

Narrator: A new car built by my company leaves somewhere travelling at 60 mph. The rear differential locks up. The car crashes and burns with everyone trapped inside. Now: should we initiate a recall? Take the number of vehicles in the field, A, multiply by the probable rate of failure, B, multiply by the average out-of-court settlement, C. A times B times C equals X. If X is less than the cost of a recall, we don't do one.

Business woman on plane: Are there a lot of these kinds of accidents?

Narrator: You wouldn't believe.

Business woman on plane: Which car company do you work for?

Narrator: A major one....

 

[pdmracing]

I don't believe in the conspiracy theories. When Racing cars Sh** happens. Brake failure can occur in any form of motorsports & does on a regular basis. In almost all instances it is due to something coming apart or not assembled right. There are many explanations to what may have happened & many are stated here, but to say DC is covering up something is way out there.

 

[JonB]

1) Im grateful for all the sharing that has gone on, and sorry that I missed it in when fresh. My reply is late and long.

2) Glad all that posted are still here to post: healthy, recovered, and STILL passionate about Vipers.

3) It is gratifying to see that D-C DID EVALUATE the incident, within 14 days, and issue a plausible report that you shared.

4) had you monkeyed with the bypass/prob valves? I suspect NOT.
Would the inspector have known??

5) D-C attorneys made it clear a long time ago that D-C employees cannot post here in any official capacity, and those who post here unofficially do so at their own risk. So PVO wont reply here.

As a national VCA officer for 5 years, I tried OFFICIALLY to get someone assigned the task. Team Viper was "somewhat willing, receptive" but attorneys shot it down. Even getting a 'committe' of 1-2-3 Team Viper guys to route answers on semi-schedule to a "ghost guru" was nixed. BEEN THERE-TRIED THAT.

[ We ACTUALLY and regularly received some unofficial guru-help behind the scenes for THIS SITE, but then SOMEONE HERE complained about the "Stump The Guru" section and that section was cancelled. Go Figure.

Some D-C access and info has been generously trickled thru (some) VCA officer conduits thru the years, but NEVER allowd to be "attributed" to PVO-CAAP-DC, etc. To attribute the info would doom its trickle.

My take is like Vic's:
-Your fluid, post-incident, was Full+. So no catastrophic leak.
-ABS can be flat-out disconnected..no mechanical 'link' to pedal.
-Master Cyl and/or PB booster must be suspect. But booster usually results in HARD IMMOBILE pedal, not a flat-flaccid one.
I vote master Cyl.
- Your cooling was Ialso INADEQUATE to your skiils and speeds.
-Since I have a 2001 ACR, I will faithfully inspect lines, and pedal-test regularly pre-flight; and midflight at ANY hiccup, Im pulling OFF. Thanks for sharing.....

 

[Vic]

JonB-

Thanks for checking in on the issue.

We still need you!

 

[jimandela]

JonB

**** lawyers! The owner of the wrecks are not interested in $
they would just like help.. it is frustrating that the cover you bass theory supercedes the help thy neighbor theory!

Any trickle info appreciated.

I agree; my suspect is the master cylinder.


Also DC you owe me one!!
I told you where your 1996 pre-production GTS was.
The powers that be know this is true.
How about returning the favor.

Best wishes
JIM

 

[lleone]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by JonB - PartsRack:
My take is like Vic's:
-Your fluid, post-incident, was Full+. So no catastrophic leak.
-ABS can be flat-out disconnected..no mechanical 'link' to pedal.
-Master Cyl and/or PB booster must be suspect. But booster usually results in HARD IMMOBILE pedal, not a flat-flaccid one.
I vote master Cyl.
- Your cooling was Ialso INADEQUATE to your skiils and speeds.
-Since I have a 2001 ACR, I will faithfully inspect lines, and pedal-test regularly pre-flight; and midflight at ANY hiccup, Im pulling OFF. Thanks for sharing.....
<HR></BLOCKQUOTE>

Jon, good to have your input! I think the same, but I'm still going to poke around with the booster just to be sure. Heck of thing to hapen if it's a vacuum line problem.

Lou

 

[SoCal Craig]

Thanks for the input Jon. If it is the master cylinder is there a fix or an aftermarket solution? Seems strange that with the number of Vipers raced that there wouldn't be something more dependable, especially considering the importance of brakes!

BTW I haven't heard about this problem (master cylinder failure due to by pass valve) on other car boards. Does this problem occur with other makes too?

 

[Vic]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by SoCal Craig:

(master cylinder failure due to by pass valve)
<HR></BLOCKQUOTE>

Craig,

That by-pass valve theory was just sort of an off-the-wall idea I had. But just a plain master cylinder piston seal failure could cause the problem too. The result would be the same, even without a by-pass valve malfunction. Pedal to the floor!

I dunno if our Vipers have a by-pass valve.

Has anyone here ever taken the master cylinder apart?

Its seems likely that it does have a by-pass valve, though. Because if you didn't have one, weepage that gets by the mas. piston seal would drip out the back of the cylinder, near the fire wall, or near the vaccuum assist plenum.

But I still have to claim ignorance, because I haven't rebuilt a master cylinder since the VW Bug one I did in high school shop class, (eons ago), and there have been many changes to automobiles since then.

Now would be a good time for me to stop talking!

<FONT size="1">Well, actually, much earlier, but you know me!</FONT s>