[Scargoes]

If during the accident, the suspension links failed, the brake line isn't strong enough to keep the wheel/brake/hub/knuckle/strut attached to the car. While the flexible brake line is stronger than in years past, it's not designed to withstand those tension forces.

This is an unfortunate event but there isn't really a reason to try to speculate what happened since we don't have any data about the incident. Let Sam, the insurance, and GM dive into the data and conclude what happened. I am sure that if Sam feels there is a safety issue he would inform us.

[TrackClub]

Originally Posted by Scargoes

If during the accident, the suspension links failed, the brake line isn't strong enough to keep the wheel/brake/hub/knuckle/strut attached to the car. While the flexible brake line is stronger than in years past, it's not designed to withstand those tension forces.

This is an unfortunate event but there isn't really a reason to try to speculate what happened since we don't have any data about the incident. Let Sam, the insurance, and GM dive into the data and conclude what happened. I am sure that if Sam feels there is a safety issue he would inform us.

Well, i think Sam's post clearly indicates there is a safety problem. Not sure how else to qualify a sudden loss of brakes.

Given he totaled the car, hit another car, and likely is in legal discussions, this could take months at best. And depending how such discussions conclude and on what terms, he may, or may not be able to comment publicly any further.

Bottom line, he clearly indicated his pedal went to the floor with no prior warning. That's a catastrophic failure of some, yet tbd cause and hence a safety issue. In my book anyway.

[supersportss]

Could be he hit something on the track and didn't see it, maybe it wasn't the car at all, at this point it's all speculation, point is wear good safety equipment, the life you save may be your own.

[Leadrightpedal]

Just curious what does ice mode do to the brakes?

[NeverDie]

https://www.camaro6.com/forums/showthread.php?t=554115

[Mountain]

Originally Posted by TrackClub

Well Sam's theory is either a brake line busted, or master cylinder failed. Those would be two easiest (and logical) theories anyway. But, who knows, there might be other causes as well depending on to what extend electronics can play a role (if they do).

I think there was at least one other case of pedal to the floor reported in the old thread. Some offeres a sticky vacuum valve as a potential cause. But frankly this is completely over my head. Given early failures were reported going back to 2016 cars, if it was a systemic issue GM would have surely fixed it by now.

An interesting aspect of Sam's accident was that a wheel came off ripping a brake line with it. That's highly unusual imo. It would be interesting to know if it was a stock wheel or not. He appeared to have been testing different tires on different rims. It would also be interesting to know what else came off with the wheel and whether the latter was in one piece, or not. And obviously when did it come off. Lots of possible dots to connect here.

Bottom line, i am glad he is fine. Testament of Camaros safety for damn sure. But also a troubling issue not really knowing for sure what happened and why.

I read through the thread you are talking in respect to: where most of the concern was with 2016MY cars and them getting reduce brake force, sometimes with minor pulsation in the pedal and a "Service Brake Assist" message popping; DTC's of C025E and U0140.
https://www.camaro6.com/forums/showthread.php?t=459802

The issues in that thread are very different than the situation in question for this thread.

Also, if there are issue with the power vacuum brake system, either vacuum pump, vacuum booster or sensor, it shouldn't reduce brake system pressure or effort to ZERO. The power brake system can only reduce pedal effort. It can only effect brake force indirectly through pedal force, but as long as someone is pressing the pedal, the mechanicals are connected and the hydraulic system is intact/sealed, there will not be a result of ZERO brake force - there will be something and enough to get the vehicle to a stop, although possibly at a reduced rate.

>If vacuum is faulted to none, you get a hard pedal and brake force should still be available.
>If vacuum is faulted to something/more than necessary, you get either a "normal" pedal or lightened pedal and brake force should still be available.

In order to have ZERO brake force, the pedal with no resistance, and dropping straight to the floor, you'd have to have at least one of the following:
-leaking/internally-bypassing master cylinder
-leaking brake line(s)
-leaking brake caliper(s)
-disconnected/broken brake pedal
-disconnected/broken brake pedal piston rod
-disconnected/broken mounting to the master cylinder/brake booster

Does anyone know if a HCU is possible of fully dumping/blocking brake force to all wheels and could it result in ZERO pedal [pressure]/the pedal dropping to the floor? I think the answer is "NO", as a fail-safe fault and that the accumulators aren't sized to allow that (not big enough to dump that amount of fluid into).

[TrackClub]

Originally Posted by Mountain

I read through the thread you are talking in respect to: where most of the concern was with 2016MY cars and them getting reduce brake force, sometimes with minor pulsation in the pedal and a "Service Brake Assist" message popping; DTC's of C025E and U0140.
https://www.camaro6.com/forums/showthread.php?t=459802

The issues in that thread are very different than the situation in question for this thread.

Also, if there are issue with the power vacuum brake system, either vacuum pump, vacuum booster or sensor, it shouldn't reduce brake system pressure or effort to ZERO. The power brake system can only reduce pedal effort. It can only effect brake force indirectly through pedal force, but as long as someone is pressing the pedal, the mechanicals are connected and the hydraulic system is intact/sealed, there will not be a result of ZERO brake force - there will be something and enough to get the vehicle to a stop, although possibly at a reduced rate.

>If vacuum is faulted to none, you get a hard pedal and brake force should still be available.
>If vacuum is faulted to something/more than necessary, you get either a "normal" pedal or lightened pedal and brake force should still be available.

In order to have ZERO brake force, the pedal with no resistance, and dropping straight to the floor, you'd have to have at least one of the following:
-leaking/internally-bypassing master cylinder
-leaking brake line(s)
-leaking brake caliper(s)
-disconnected/broken brake pedal
-disconnected/broken brake pedal piston rod
-disconnected/broken mounting to the master cylinder/brake booster

Does anyone know if a HCU is possible of fully dumping/blocking brake force to all wheels and could it result in ZERO pedal [pressure]/the pedal dropping to the floor? I think the answer is "NO", as a fail-safe fault and that the accumulators aren't sized to allow that (not big enough to dump that amount of fluid into).

This is good stuff. Apparently ABS pump failure should also be added to the list:

https://youtu.be/ceN0a-nPUZw

[Scargoes]

Originally Posted by TrackClub

Well, i think Sam's post clearly indicates there is a safety problem. Not sure how else to qualify a sudden loss of brakes.

Given he totaled the car, hit another car, and likely is in legal discussions, this could take months at best. And depending how such discussions conclude and on what terms, he may, or may not be able to comment publicly any further.

Bottom line, he clearly indicated his pedal went to the floor with no prior warning. That's a catastrophic failure of some, yet tbd cause and hence a safety issue. In my book anyway.

If there was an issue with a manufactured part, say a brake hose didn't get crimped 100% in the fitting, it's not necessarily a safety concern with all vehicles. It may be a one off problem or a batch problem. This is why recalls aren't always issued because 1 or two cars have a concern. Or, say a rodent chewed partially thru the hose after he had inspected the vehicle but before he went out on track. And thru use, the hose finally failed. That actually happened to me, but luckily I was at an autocross and not a track day. A scenario like that would be out of GMs hands. So to throw out that there is a safety concern without an adequate investigation is kin to the one guy on here bashing the Moreno camber plates about their inadequate engineering design when it turned out he caused all the problems by installing them wrong.

[TrackClub]

Originally Posted by Scargoes

If there was an issue with a manufactured part, say a brake hose didn't get crimped 100% in the fitting, it's not necessarily a safety concern with all vehicles. It may be a one off problem or a batch problem. This is why recalls aren't always issued because 1 or two cars have a concern. Or, say a rodent chewed partially thru the hose after he had inspected the vehicle but before he went out on track. And thru use, the hose finally failed. That actually happened to me, but luckily I was at an autocross and not a track day. A scenario like that would be out of GMs hands. So to throw out that there is a safety concern without an adequate investigation is kin to the one guy on here bashing the Moreno camber plates about their inadequate engineering design when it turned out he caused all the problems by installing them wrong.

I completely agree, given a root cause has not been identifed yet. And we also dont know if this is due to a rodent, some sort of a user error, a faulty part, a badly installed part, a new supplier, or whatever. We also dont know if this was a one off, or something involving a batch of cars, or whatever. Hence a proper investigation is critical especially that it was a brand new car with only 1k on it.

BUT, i can't think of another word to describe the actual event other then a safety issue. Whatever the cause. As a matter of fact Id say zero brakes would be an ultimate safety issue especially at a track. Ford has just recalled all turbo F150s for brake issues and will be replacing all master cylinders and brake boosters. Dont know how many owners had to report issues before that happened.

The problem is, IF this is a bad batch related (for example ONLY), it may take a few of such cases for any type of a recall.

Sam was incredibly lucky not to end up 6 feet under.
That's why i started this thread to:

1. See if there were any other folks that have experienced a similar problem and if so to hopefully get more info from them.

2. Give our community an oppprtunity to share views on what potentially could have caused a complete loss of brakes. Perhaps so we could check some components proactively. Or pay attention to something that we may not (like some folks hanging calipers off of brake lines, or not checking for rodent damage, etc).

3. This is not intended to cast blame on GM, or Sam, but to have a productive discussion and hopefully learn something.

Cheers!

[3.8TransAM]

Also, was not the car involved a used car as well? Can't remember for sure , but that would muddy the waters further.

[TrackClub]

Originally Posted by 3.8TransAM

Also, was not the car involved a used car as well? Can't remember for sure , but that would muddy the waters further.

No. Brand new car with 1500 miles on it.

[Scargoes]

Originally Posted by TrackClub

BUT, i can't think of another word to describe the actual event other then a safety issue.

In the terms of an OEM, it would just be labeled as an 'Event' that raised a 'Concern' with whatever rating system they use. My last employer used P1-5 with P1 being critical and P5 being the lowest. If this is the only known event, it would start out as a P5 or P4 because it is a singular event that took place under very specific and special conditions.

[TrackClub]

Originally Posted by Scargoes

In the terms of an OEM, it would just be labeled as an 'Event' that raised a 'Concern' with whatever rating system they use. My last employer used P1-5 with P1 being critical and P5 being the lowest. If this is the only known event, it would start out as a P5 or P4 because it is a singular event that took place under very specific and special conditions.

That would not surprise me. Especially given nobody has offered similar examples thus far. Cheers!

[JamesNoBrakes]

Originally Posted by TrackClub

Well that is stating the obvious

Could be a catastrophic line failure (various reasons possible here)
Could be an MC fault
Could be a caliper falling out
Could be electronics if they play a role (dont know)
Could be a wheel falling off
Etc.

We need a GM engineer to list possible causes and then try to match the most probable one to the actual situation. The one i dont understand is a wheel being ripped off and taking a brake line with it. Unless a whole hub came apart.

Yeah, but as the proximal event, there is likely evidence of brake failure if that is indeed the case. Master cylinder wouldn't hold pressure when you stomp on the pedal. Lines or fittings would be leaking fluid. If it's enough to just let the pedal go to the floor, should be pretty obvious. Even with a totaled car, the brake system is likely still functional, except for any obviously ripped out parts in the crash. I've bled a LOT of brake systems and fluid doesn't just disappear to reappear later on. If pedal is going to the floor, brake fluid went somewhere or wasn't there to begin with.