Truck Breaks Failure Information

It is estimated that brake-related issues are the most common reason for trucking accidents. Brake failure is a contributing factor in roughly 30% of accidents involving large trucks, according to the Transportation Research Board’s (TRB) 2010 Report, “Trucking 101,” All told, brake problems lead to over 40,000 trucking accidents each year.

It is estimated that roughly 50 percent of commercial motor vehicle out-of-service violations cited during roadside inspections (such as the Commercial Vehicle Safety Alliance’s annual Brake Safety Week) were for brake related violations.

Top 10 Reasons why brakes fail in the mountains (but may not fail otherwise).

1. Human error – failure to pay attention, failure to properly gauge distances and apply the brakes in time, slamming on the breaks leading to skidding and loss of control

2. “Hot brakes” or Overheating – Hot brakes and wheel bearings can come about from dragging brakes that result in friction and abnormal brake temperatures, as well as wheel grease fires that spread to the tires. If the brakes significantly overheat they can lose functionality.

3. Overloaded trailer – A truck pulling too much weight requires excessive braking distances even when using brakes in good condition. This endangers the public safety, especially in situations demanding hard braking. Overloaded trailers place extra stress on the braking system which may fail especially when they are poorly maintained.

4. Defective brakes/parts/product liability – obviously in rare circumstances you will see manufacturing or design defects in brake systems.

5. Brake imbalance – Brake imbalance occurs when some brakes work harder than others or there is more “torque” that is being created over certain brake components or areas than others. This may be caused by using mismatched mechanical components or when the pneumatic system applies more air pressure to some brakes than others. This uneven distribution may cause some of the brakes to lock up and lead to skidding and jackknifing. A brake imbalance can also cause some brakes to overheat when going downhill.

6. Inadequate brake maintenance – While some trucking companies diligently keep up with their maintenance, some do not and are not caught in time by a DOT brake inspection to prevent a deadly truck accident. Braking deficiencies will sometimes allow the truck to brake in ordinary circumstances but not when hard braking is required in an emergency.

7. Brake fade – Refers to “reduction in stopping power that can occur after repeated or sustained application of the brakes, especially in high load or high speed conditions.” i.e. over-application of the brakes over a prolonged period of time.

8. Friction fade – Which is a reduction of friction between the brake pad and drum or rotor. Friction fade can occur if the brake parts were not properly produced, the pads do not correctly fit the drums/rotors because they are twisted or poorly remanufactured, the drums/rotors are not resurfaced often enough, or the pads are not frequently replaced.

9. Mechanical Fade – Brake drums may experience a condition where the heat generated by friction causes the drum to actually expand outward, increasing its diameter. If the drum increases enough, the brake pad can lose effectiveness since it cannot create the proper friction to slow the vehicle enough to prevent it from losing control.

10. Fluid Fade – This occurs when the friction generated by the brakes causes the fluid within the system to boil and then vaporize. Hydraulic braking systems, which is what most tractor trailers have, require fluid to activate the pads when the pedal is pushed. The hydraulics will not work effectively if the fluid is in a gaseous state.

What kind of maintenance needs to be performed on your brakes?

CFR Regulation 396.3(a) requires that all motor carriers “systematically inspect, repair, and maintain… all motor vehicles subject to its control.” It also provides that all “parts and accessories must be in safe and proper condition at all times.’

FMCSA regulations also have detailed rules about who is permitted to perform brake maintenance, testing, and repair. The carrier has a responsibility to makes sure only qualified people work on the brakes. This means folks who have completed a State, Canadian province, Federal agency, or union training program, a State-approved training program, training that led to attainment of a State or Canadian Province qualifying certificate to perform assigned brake service or inspection tasks, including passage of CDL air brake test in the case of a brake inspection, or one year of brake-related training, experience, or combination of both.

Pre-trip Inspection

FMCSA regulations state that “[n]o commercial motor vehicle shall be driven unless the driver is satisfied that… [the vehicle’s] parts and accessories are in good working order,” including the brake system(s). (49 CFR 392.7)

49 CFR 392.9 also requires that a truck driver inspect his or her truck and cargo:

>Within the first 50 miles of a trip,
>Whenever the driver changes duty status, and
>When he drives more than three hours or 150 miles.

Drivers are also required to complete a post-trip inspection and to file a “driver vehicle inspection reports (DVIRs)” outlin