Brake Failure at 24K Miles

[CT5VBW]

Greetings all! Pulled into a parking lot the other day and did a U-turn to park in a corner by myself. on full lock to lock turn heard/felt a pop and then pedal went pretty much to floor. She then said brake failure, max speed 43mph blah blah blah.

Took it in and after a bunch of bleeding and testing and stuff multiple times, they had to call GM TAC and ultimately replace master cylinder, brake boost, and ecm with programming, etc.

All appears to be back to normal, but just wanted to get some feedback on two things:

1.) master cylinder failure seems odd to me as car is only 2 years old with just a tad under 24K mi. Anyone else have this happen?
2.) The notes say that when they called TAC, the TAC guy said "a lot of cases, none closed". Ultimately recommended to replace master cylinder which obviously worked.

I know stuff happens, but I'm concerned most about #2. I really don't want to be driving around a high performance car worrying about the brakes going out since there are "a lot of cases, none closed."

Other than that, my gurl has been wonderful....!!

Appreciate any thoughts/feedback

 

[rdollie]

I haven't heard of this one. What year is your BW??

 

[CT5VBW]

I haven't heard of this one. What year is your BW??

Its a first edition 2022.

 

[KatyTxCT5V]

I have a 22, but nowhere near your mileage, however, first time hearing this type of failure. Mine is 2yrs old.

Of course, I’m sure not everyone that drives a Blackwing is a member of this forum, their loss, lol.

Interesting…

 

[Mcard23]

Mines one of the first 22s and I’m at 25k miles, no brake issues here. Hope this isn’t some sort of trend that develops

 

[rdollie]

I've got a #44 vin from MY22 with about 40k miles and no brake issues (of course I've changed the pads and rotors once and brake fluid 2-3 times during the past few years.)

 

[jbawden]

So you had brakes, but not the normal pedal or performance? For being the last gasp for a mostly analog experience, the brake by wire deal is a let down. I wish they would have left that tech to the Lyriq and similar science experiments.

 

[rubberduck]

A couple years back I was off-roadng in my Jeep, coming down a very mild hill and brake pedal went to the floor. Pumped the brakes many times and got some braking back. Between that and having a 6-spd it was manageable. Could have gone very badly if I didn’t have runway and was approaching a cliff. Get out and find a huge puddle of brake fluid under my right front tire. Turns out the brake line at the caliper came loose. I always carry tools and brake fluid so easy to remedy. Added that to my regular pre off-roading checklist.

Makes me wonder how a brake by wire system would handle that situation.

 

[MookdocOE]

If all we're seeing is a few LT4's die and an isolated brake failure at 24k I would say the platform is pretty "Rock Solid" There's not that many units of CT5-V BW's anyway but these forums are not riddled with problems like other vehicles.

 

[AC2024]

So you had brakes, but not the normal pedal or performance? For being the last gasp for a mostly analog experience, the brake by wire deal is a let down. I wish they would have left that tech to the Lyriq and similar science experiments.

I would philosophically agree with this wholeheartedly-but I actually like everything about the brake feel and performance so I guess the pragmatist in me disagrees with the philosopher! I do generally feel this way about the E-LSD- the capability is jaw dropping but it feels very synthetic and digital to me… much more so than the brakes.

 

[BimmerFan]

I don't think it's the brake by wire (BBW) system that failed, and presumably the system will still work on pure hydraulics if the electrical portion goes FUBAR, just with more effort and less effectiveness. GM also uses it on the C8 Corvette and probably some other things. Most of these new-fangled high tech things are first introduced on the Corvette (like our suspension system) before filtering down to other platforms.

Unless of course you are driving a BMW, since they recalled how many million cars d/t BBW issues?

 

[poor-sha]

I’m curious whether you have CCBs or not? Manual or auto? Any signs of a fluid leak?

Wasn’t there a recall that had to do with repositioning the brake lines? I could see where if you had the wheel at full lock and there wasn’t enough brake line play something could leak or pinch a line.

 

[jbawden]

My understanding is when the BBW "fails" there is a physical plunger that offers brake operation. I think this is 100% BBW failure and it went to fail safe mode, like its supposed to. The OP will have to clarify, but sounds like he still had brake power so likely not a traditional hydraulic failure (line break, or similar).

 

[CT5VBW]

hey all, some responses here. When I stopped (perfectly in the target spot BTW ), the pedal felt like it went to the floor to me. I was with an Attorney (mental note: could be good or bad situation there) and she said "just restart the car and maybe that will fix it". Funny, because I run IT for our company so I said "This isn't a computer! but I will oblige since I'm impressed you have listened to our sage IT advice to fix your computer when you screw it up!" Before I restarted the car it said "brake system failure, max speed 62mph", when it came back on it said "brake system failure, max speed 43mph". So we both agreed it appeared to be a leak. We checked and no leak anywhere. After lunch, turned car back on and same message, still no leak. I didn't attempt to drive the car and had it towed to the dealer which is funny because my attorney pal said to just limp it in!

The dealership tech noted when he tested the car, the "pedal is soft". I have non-CCB brakes with a manual, no tracking of car, and don't really beat on the car (at least braking-wise). However, they noted my brakes are 3mm and "dished rotors". My favorite part of the whole documentation is the statement mid-paragraph, "THIS IS A BLACKWING".

So I am with poor-sha. I am convinced that it was something mechanical and it would really make sense that it was a pinched brake line or something and didnt leak. Also, (and I forgot about this), a few weeks before I did have a heck of rock kick up under the car so maybe it kicked up in the right spot and damaged something without creating a leak??? Still somewhat concerning since dealer didn't list replacing any lines, but like i said, so far so good. brakes feel just as good as before the incident.

Only reason I posted is because I can deal with almost type of failure, but brake failure concerns me... like the other poster said "coulda went off a cliff..."

 

[KatyTxCT5V]

Interesting and thanks for posting the findings. So they did replace the master cylinder with booster and module. Good notes by the tech. Glad it was resolved for you.