SLandstra_Z06

I had a sudden and total ABS failure in my 2009 C6 Z06 at NJMP Thunderbolt last Saturday. I was going 140 and hit my brakes at the normal brake marker at the normal pressure and realized right away that I had a problem. I heard and felt the front tires lock up immediately. I looked down at the DIC quickly and saw it flash "Service ABS System". I thought, no ****, but can you let me stop one more time before I get that service???

I started pumping the brakes feverishly, to no avail. I tried turning the wheel to throw the car sideways, but I had already worn through the rubber and was driving on the steel cords of the Hoosier tires, so turning wasn't an option. I since learned that you need to fully release the brake pedal in order to get vacuum back in the system and stop the tires from locking. I was able to scrub off about 100 mph, but still drove straight through the curb, over several feet of runoff asphalt and through the gravel trap before hitting the tire barrier at the end of the front straight. I hit at 35 mph, head on.

Considering what could have happened, the damage was pretty minor. Luckliy, there were two rows of tires in the tire barrier in front of the guard rail. Those two rows of tires absorbed a lot of the impact.

The car is at Phoenix Performance having an evaluation of the damage. I think it's confined to all plastic parts. Lucky. Now we need to figure out what caused the ABS to go nuts. Never had that happen before, but I want to make sure we find out what happened and resolve it.

Check out the in-car video. Feel free to watch all of it, but the fun lap is number 7 that starts at about the 9:00 mark of the video.

http://www.youtube.com/watch?v=AcF53...ature=youtu.be







Steve

ErnieN85

I'm glad your ok
as for the problem......

mdaniel

Definitely a frightening situation.
Could the e-brake have helped at all?

Short-Throw

Steve glad you're okay and it happened where all you found was pea gravel and a light tap.

John Shiels

Light tap probably did a good bit of damage although it could have been way worse. Down shifting is another option but it all happens so fast.

Hope it is all minimal damage as much as possible.

RX-Ben

I have had the same happen at NJMP, a few times.
Check all your abs wires and connectors around the hubs. Most likely either one of the jackets on the wires is worn bare or a wire has simply failed (I had an SKF wire simply crack in half from heat) or the connector has gone south.
If they all look good then start poking around various wires with a voltmeter when spinning the hub, with the hub mounted. Most likely you will find that one of the hubs is not delivering a signal past one of the connectors.
Weatherpak connectors have worked flawless for me, in place of failed stockers. Polarity does not matter.
If you remember, I rewired an SKF a couple years ago at an RTR event during a rain day (of all things) at Pocono. The need for this was that one of the abs wires coming from the hub simply cracked in half. I used high temp teflon jacketed wire and weatherpak connectors and it has worked fine ever since.

Easiest thing to do is to give it a short drive and then let the error codes guide you. Simply swapping in a new hub is not a guaranteed fix, as the inboard connector may be defective.

C5-vette

That sucks. What head and neck restraint are you wearing?
I know it was a lighter impact than it could have been, but it
looks like you reached the end of your tether. Could you feel that?

JDIllon

Glad to hear you are OK and hope the car is not to badly hurt. JD

SLandstra_Z06

I have a Professional Hans Vision system. I can't tell you I really felt it work, but I'm still glad I have it, in case we don't get the ABS fixed and I really need it at a later date... Just kidding, we'll fix the ABS...

C5-vette

in case we don't get the ABS fixed and I really need it at a later date... Just kidding, we'll fix the ABS...

[/QUOTE]

HaHa good stuff, I hope you NEVER need it!
thanks for the response

fatbillybob

All that Ben posted I agree. Same thing happened to me destroyed 4 nearly new tires. $1400 bucks bye-bye!

In my case I just unplugged and re connected all 4 wheel sensor connections. Maybe track rubber banged the connectors???? It has not happened since. That was 2 race weekends ago for me. There does not seem to be a prevention protocol for this just a fix after the fact.

mcar00

Glad you're OK! That's some pretty scary stuff there.

Brake failure happens occasionally though and I guess it's good to have a backup plan thought out in advance. Having the composure to execute it is a whole different story though. I think I saw Johnny O bust a rotor at the end of the back straight at Sebring and he had the composure to shift it into 2nd gear to spin the car and scrub off some speed. Still hit the wall but at a much slower speed. Does it make any sense in our case to yank the emergency brake to put the car in a spin? Any input from guys who have thought this out?

cleanerPA

Sounds like you had an EBCM failure- glad you're okay. The guys at Phoenix should be able to get your car sorted out, they fixed my brake problem, although yours was a lot more serious.

It's scary that your fronts locked up without warning- getting off the brakes even momentarily didn't release the brakes? I haven't had this type of failure experience, but with most cars with lockup (like on slippery surfaces, without ABS), getting off the pedal will allow the wheel to unlock. That sounds more like my Mercedes CLS experience with the SBC brakes (brake by wire) where the car nearly killed me.

Painrace

WOW, Steve. Glad you are OK! That looks like a neat track. Please keep us posted on damage and your progress.

Jim

Bill Dearborn

Have been through this scenario a couple of times after experiencing no brakes in a student's car and my own a few weeks later. Both of those were loss of brakes where this one looks like it is due to too much brake pressure and when the ABS failed there was too much brake. In any case a person needs to think about they how they will react before the situation occurs. It isn't something you can easily practice since practicing will be extremely dangerous.

I think in both cases of failure the driver's first reaction should be to pump the brakes. All modern cars have dual brake systems. Some of them are split front and rear and others like the newer Corvettes have a dual diagonal split. When the pedal drops to the floor in most cases with a dual brake system one of the systems is still functional but you have to build up some pressure in the system. If you don't get braking within two pumps it is time for Plan B which is to look at how far you can extend the braking zone into the turn and any run off area off the turn, if that doesn't look achievable then spinning the car along with applying the parking brake is another way to slow the car, then of course just using the parking brake. In this case with the ABS taking a dump the driver is all of a sudden driving an old car with nothing but base brakes. Then the driver has to go into threshold braking mode. Having driven plenty of cars without ABS I have never had to completely lift my foot off the brake to modulate the brake pressure. Most drivers in the snow belt have plenty of experience with doing this so it comes second nature to them.

Bill

sothpaw2

Thanks for posting...didn't know you had to come all the way off brake due to vacuum pressure. Certainly something to plan ahead.

sperkins

The lack of screeching tires is amazing.

RX-Ben

They screech but it is too late by the time you hear them. Something weird happens with the sound and they sound much different than the typically squeaks when cornering. Very hard to explain, but you learn to rely on other things if the abs is taking the occasional unannounced vacation. The giveaway, though also a bit late if you are pushing, is that your braking rate flatlines and you realize that your mental image and inner ear "image" of the braking zone is not meeting expectations. It jars you back to thinking about the present as opposed to focusing ahead, at the apex/exit, as you just missed any hope of either.

I have found that it takes a full lift, or at least what feels like one, to get the tires unlocked and then you can go back to guessing at threshold. While your foot is dealing with this, you need to be planning other exit options.

fatbillybob

Bill,

I do not think this is what the OP experienced. In my case and in the case of a few others what happens is the ABS brakes fail in the all 4 locked state. You have no braking because you are in a 4 wheel slide at over 100mph. None of these events happen at under 100. In my case releasing the pedal did not seem to do anything. My cabin was still being filled with tire smoke as a left the tarmac with foot off the brake but 4 wheels in a straight line skid wheels locked. This is not a case of default non-abs braking. If however you survive the failure and continue to drive then you got default non-abs braking on subsequent braking events. It is the first failure that is a killer. I think it is a dangerous design flaw that make me think of permenantly disabling my ABS.

dvandentop

damn steve gld you were able to scrub off some speed or woulda been alot worse!!!

Sucky about the damage but hopefully not too bad. Atleast you are ok and it is almost end of the season.

What video and data logger are you using?