A Facebook post tells the story of a Bronco driver who makes a panic stop to avoid hitting a deer. Then the Bronco fried a few more miles. A fire consumed most of the van. Fortunately, the two passengers were not injured. The question remains whether this is another security issue or a fluke.
Can line pressure cause a Bronco brake line to fail?
This happened in Iowa according to the Bronco 6th generation Facebook page. A friend of the owner of the Bronco was driving it with a passenger. “Had to slam on the brakes to avoid a deer, and seven miles down the highway, the ABS locked up the brakes and blew out the brake line, and then it shorted out and started catching fire,” the sign read.
If the pressure from the ABS system was enough to rupture a brake line, that’s a huge safety issue. But it doesn’t seem possible, especially since stainless steel brake lines combined with ABS systems have been around for decades. If the brakes came on partially due to a system malfunction, then the brakes could have gotten hot. But going only seven miles, it doesn’t seem far enough to start a fire.
Broncos equipped with 2.3-liter engines have vacuum booster brakes. Those equipped with the 2.7-liter have electronic power brakes. We don’t know what engine this particular Bronco came with.
Have there been any reported problems with Bronco’s brakes?
There have been reports of problems with the brakes. One is for the vacuum lines to become contaminated on the 2.3-liter models. The brakes will preload but then quickly clear. Preload occurs when there is contact of an object with a bumper, or optical sensors detect a possible collision.
Preload reduces the time to apply the brakes when a collision is imminent. A brake warning or brake system warning light is an indication, and the “locked ABS” described was likely the ABS module making the brakes feel firm.
In reviewing the recalls and complaints from the National Highway Traffic Safety Administration, we see nothing similar to this incident. Bronco Sport models had a brake recall in late 2021 due to improperly manufactured rear brake linings.
Is brake fluid flammable?
So without pointing fingers, we wonder if there’s more to this story than is being reported. Brake fluid is flammable because it is a glycol based fluid. So possibly if it came in contact with the exhaust it could catch fire. It has a flammability rating of 1, which means a flash point of 73.4 degrees F and a boiling point of 95 degrees F.
But the question is how can you burst a stainless steel brake line? The PSI ratings indicate there isn’t enough pressure to do that. That is why copper lines are prohibited. However, today’s copper-nickel brake lines are legal. They are rated only slightly lower than stainless steel.
If we hear more about this incident, we will update this post.