So around 5 this evening i was headed to the local logans roadhouse to meet this pretty little thing for a date. As i turned into the parking lot i heard what sounded like a gunshot go off under my hood. Immediately following the gunshot about a 4 foot fireball shot out of the driverside of my hood. And immediately following the fireball my brakes went out. (This all took place in about a half a second) luckily ii was pulling into a parking spot as all this happened. I popped the hood and quicly put out the fire. I found that apperntly if a wire shorts out on the hardline off of the proportioning valve that the hardline will explode. Just as i removed the 2 remaining pieces of the hardline my date pulled up. Perfect timing huh lol. Well this provided for a very interesting first date. Im still trying to figure out what made the wire short out. They havent been there very long and they were inside of a protective conduit.

 

Pretty much any metallic part that you connect directly to the battery will be blown away. No fuse in that line?

 

There was deffinatly a fuse. That why its puzzling me so much about how this happened. Im at a loss

 

Edit double post

 

If there was a fuse on the circuit, and it didn't blow. The wiring was too small, got hot and ignited something under the hood.

 

The fuse blew, and the wiring on that circuit is either 6 or 4 gauge, so its not because of the wiring. So far my guess is that when the wire shorted out it ignited the brake fluid in the hardline as the fuse blew

 

gottcha now. It wasn't running into an amp or stereo was it? Actually that doesn't matter. What was the power lead running too though?

 

All of my auxiliary lighting

 

I'm an idiot, I just read your first post again. You have it figured out, just have to look for the evidence of the cause. (Seems like your wire power lead went to ground.) Just for shiggles brake fluid by its self is not flammable. I just did an experiment, it's like candle wax. You can take a torch to it and nothing, take paper and soak it in it and it burns for a while, but not explosive. Under pressure though? I have to have a couple more!

 

Keep in mind that the purpose of a fuse is to prevent fire and not to prevent any/all damage. Common automotive fuses are relatively slow to act, and certainly much slower than the time it takes to do some damage.

What probably happened: A misrouted and improperly protected wire's insulation was finally abraded enough to allow completion of a circuit that amounted to a short across the battery terminals. Automotive fuses being relatively slow devices, in the time it took for the fuse link to melt open there was a peak current of hundreds of amps flowing in that circuit, well more than enough to heat a very small region of aluminum brake line to its melting point. The pressurized brake fluid spewed out through that hole as a fine mist which ignited when it met that hot metal. Some time later the fuse link melted open and the current flow immediately stopped, the heat rapidly dissipated, the brake fluid vapor fire went out, and some time later your brain registered that something was happening.

Though the instantaneous energy was high enough to do all of that, the duration of the event was so short that the total energy was very low and there was never any danger of anything of substance igniting. If you'd had a leaky fuel rail spewing gasoline vapor it might have got interesting in a helluva fine hurry, but there wasn't enough energy there to light a cigarette.

So when you're in there fixing what got broke, take the time to reroute and properly protect those wires. It's good to ensure that fuel leaks are just stinky annoyances and not conflagrations.