Often there are obvious signs of a mechanical problem before failure occurs. Signs such as fluid leaks, odors, changes in operation, performance problems, slow cranking, spongy brake or clutch pedal, noises, gauge readings and many other symptoms are typically present before failure occurs.
For example:
Green fluid under the vehicle indicate there is a coolant leak and a failure will occur if the problem is not reported and addressed.
Visible fluid or brake fluid present in the vicinity of the wheels, or anywhere outside of the sealed brake system is an indication that failure will occur if the problem is not reported and addressed.
Metal to metal grinding sound when the brakes are applied indicates there is no brake lining remaining and is an indication that failure will occur if the problem is not reported and addressed.
Dim lights, slow cranking while starting indicates a charging system problem is an indication that failure will occur if the problem is not reported and addressed.
Most mechanical failures on UPS trucks DO NOT occur without warning. The same theory applies to personal vehicles. Does your personal car just stop working without clear and obvious signs? Not usually, but it will eventually fail if the signs are ignored.
On the road, and in the building, I observe missing marker lights, bald tires, fluid leaks, odors (burnt clutch and brake linings, coolant and electrical odors) and other obvious items that should have been detected and reported during pre-trips, post-trips and throughout the day during normal operation. These items go unreported and obviously un-repaired. Suppose it was reported and not repaired, does this mean it should be driven until it does fail just because “you’re covered” by reporting it? What if a problem is reported and no mechanic indicates that a repair was made? Drive it any way? What if the attempted repair didn’t resolve the problem? Drive it anyway? What if not reporting, or continuing to drive a vehicle with on obvious sign of a failure leads to a four vehicle accident and seriously injures or kills someone?
In the case of this brake failure accident it is possible that there were no obvious warning signs. There is not enough information posted to determine exactly what happened or what signs were present, even if the wheel cylinder was the cause.
There are mechanical failures that have no warning signs, but based upon what I see we could do a lot better at preventing most mechanical failures with a little attention to the warning signs and by following the DOT Pre-trip, post-trip and DVIR procedures.
For those of you talking jack stands, jacks, and removing transmissions you’re making ridiculous comments to inflame the situation.
Pay attention to the obvious warning signs and report them. Don’t operate the vehicle if the problem has not been addressed by a mechanic or qualified individual.
On you next trip through a UPS building look for the mechanical failure warning signs, fluid leaks, missing lights (indicates no pre-trip), odors and unusual noises. Walk over to the vehicle and look in the book. I’ll give you odds that the signs are not reported and possibly the book has not been filled out correctly for several days.