Krispy

At the track this weekend a fellow competitor had a terminal brake failure with COMPLETE loss of stopping power and with zero prior warning while entering a brake zone requiring a deceleration from approx 150kmph to 60kmph. Luckily the car did not hit any concrete and was able to come to a stop after a spectacular (horrific?) trip through the infield, things could have ended very differently.

The cause of the incident was that the front OEM brake line on this early year regular C6 broke (actually it completely detached!!!) at the crimping point where the brake line mates with the caliper at the banjo bolt. The car has been on the track approximately 10 times prior to this event and all parts were in good condition. I do not believe the vehicle had any prior off track incidents.

The thing that shocks and concerns me about this incident is;
a) that ALL four brakes failed at once with no warning, the pedal was hard at the previous braking zone. I have always been under the assumption that modern cars have brakes lines on two unique circuits, so failure would be restricted to the ruptured brake line and the adjacent rear brake. However the car would still stop, eventually.
b) that an OEM brake line would sever in this manner.
c) given the dual circuit theory did not hold in this specific case, could something else be wrong with the vehicle or does this experience hold for all C6 Corvettes, all Corvettes, all GM products, or all cars?

I have searched through the old forums posts but wasn't able to locate a similar incident. Is anybody aware of this happening before? Does anybody know who supplies GM with brake lines for the vette? Did they have a manufacture change at some point?

Frankly, given that we are pushing speeds near 250kmph into some brake zones having any chance (within reasonably controllable factors) of a repeat situation is unthinkable, and unacceptable.

0Randy@DRM

Sounds to me like a rock came up and ripped off the line. Most pro drivers have had freak brake loss, therefore they give the brake pedal a tap before going deep into the braking zone. Safety check.

We sell Stainless Steel brake lines just for this reason. They hold up to track conditions much better.

Randy

stano

I was told in the beginning when I started racing that SS brake lines were a must so debris wouldn't cut or sever a line. I'm glad I heeded that warning.

I'm glad everything turned out good for the driver, it could have been worse. Maybe he hit something that caused it to separate like that...track turd or rocks maybe...?

just saw your post Randy...I'm slow like on the track

0Randy@DRM

I'm slow too Mondays

wallyman424

This stuff is no joke. NASA-MidA lost a great guy last year due to a rubber brake line failure into T1 at summit. It just popped out of the crimped fitting. Whether that's due to a rock, rubber or dry rot doesn't really matter.

Put SS lines on there, and check them ALL the time.

stano

Who's joking about it?

wallyman424

not implying that anyone's joking, just saying its important.

one of them there figurines of speech.

davidfarmer

in a dual zone system, the pedal will get really soft, but you will still get some braking to the other end of the car. I had a slow failure once, and even though half of the master cylinder pumped dry, I was able to brake early and finish the race using only front brakes (only partially applied, as the pedal went to the floor).

I imagine it felt like a 4-wheel failure, simply because there no way to stop a car with less than half of your brakes without KNOWING it ahead of time, but probably was just the one corner causing the failure.

I'm still a fan of OEM lines. They are strong, they have some "give", and they don't fail often. In my 20 years racing, I've never had a rubber line fail, but I've had several SS lines do so (usually kinking around the crimps). SS is great, but required regular checks, and must be installed so that there is absolutely no strain on the line at all, even during maintenance (it when suspension is drooping)

stano

larryfs

the ss braided lines require so much maintenance, it's not worth it for HPDE;s. I always brought new GM rubber hoses, and never a problem.

the ss braids collect small pebbles, and abraid the line inside.

jiggyracing

to answer your question, i know of two similar events. one with me in my 2005 c6. happened when i first purchased my car and it was still a daily driver. happened just as you described. we were at an airport in St. Johns, AZ and fortunately i had a long runway to cost to a stop. put stainless steel lines pronto after that.

more recently, happened in AZ at the end of a long straight to another car and driver. thankfully wet ground (it had been raining recently - yes it does rain in Arizona) slowed him down without rolling the car. i believe his is a 2006. he switched to stainless steel lines.

anybody else out there?

that's at least 3 different times. i would say deserves at least a warning to all early c6 cars to consider steel brake lines. any more reports and i think even more then that should be done

kelp

This widespread problem and is rare but prevalent with GM hoses of the crimped-on configuration. There is a 2006 recall on power steering hose and engine fire on many GM models, and other recalls. I had an oil hose fail and a subsequent fire. Therefore I have redone most GM hoses with double clamps and push-to-lock connectors. They fatigue and break given time.

meldog21

Could be maintenance related as David mentioned. I recently had to replace my rear lines because I was an idiot and worked on my suspension while leaving my calipers mounted. I stretched one of my SS rear lines from suspension droop and it caused a leak.

That was an $85 mistake. I had to wash the bottom underside of the car every time I drove it for over a week until the new lines came in. Lesson learned. Luckily, I needed to bleed the brakes anyway.

By the way, if you have oversized rotors you need slightly longer than stock lines. This applies more in the rear than the front.

Dog

C6400hp

Not anymore most good vendors ( I have stoptech) use a stainless line encased in a clear poly outer cover to eliminate this problem of the past.

0Randy@DRM

I have my mixed feelings about wrapping the line. I have found after use the plastic starts to wear and break down. Causing a area for the dirt, grime and crap to get in. Then you can't get it back out there. Doug's 1974 racecar uncoated brake lines lasted 30 some years. We have people with over ten years on our brake lines.

Randy

CP Thunder

I am thinking the car might have had quite a few brake jobs since it had been tracked (10 times)? Even ONE incident of the caliper falling (either balanced on the a-arms or hung by a wire) during rotor/pad swaps and hitting the end of the brake line is enough to weaken crimp or press joint........just a thought.

2K3Z06

I was thinking the same thing, caliper fell off the a arm. We all done that once.........

ghoffman

I have got to disagree with you on this Randy, alot has changed in 30 years. The jacketed Fragola lines we use and sell never crack, and no dirt gets into them. I think the jacketed lines are the only way to go these days.

GrantB

Regardless of where the line was damaged (during a rotor change, a rock on the street, a piece of metal at the track, etc) its probably going to fail when its under the most heat and pressure: at the track.

CP Thunder

Murphy will always rear his ugly head..........that is a fact..........