The important role of brakes in the safety of a semi-truck has never been more evident as nearly 30 percent of trucking accidents are caused by brake malfunctions. Brake failure can be deadly to operators and to other drivers that share a road with trucks.
Warning lights and fault codes aim to alert drivers and maintenance technicians to a problem with brakes and their components. However, a driver must also rely on handling experience and increased awareness to recognize a problem with a braking system. Learn about how to be more aware of a problem with these two crucial brake conditions.
1. Brake Timing
Brake timing can make a difference in how your tractor and trailer safely perform as a unit during a stop. Under normal circumstances, rear brakes engage first and slightly before those of the tractor. Rear brakes must then release virtually immediately.
Causes of Poor Brake Timing
Brake timing is regulated by a system of pressurized valves that control air flow from the tanks leading into the brake chambers. Different valve pressure settings determine when the brakes can apply, and certain conditions contribute to their effectiveness. For example, blocks and kinks prevent the quick release of air at the right time.
This phenomenon not only applies the brakes for longer than necessary but can cause brake delays.
Effects of Poor Brake Timing
Poor brake timing often results in tractor brakes engaging out of order. This forces the trailer to strike the tractor or work harder to stop forward motion. Problems like these cause instability and offer less control during a skid, or worse, jack-knifing.
You can become more aware of brake timing problems by the way your rig feels during a stop. A sensation of pushing from behind while braking means the trailer engages later than the tractor. You may also feel some resistance after braking and at initial throttle up. Both of these scenarios indicate problems with application and release timing.
2. Brake Balance
The right brake balance means each wheel receives the right amount of torque at the same time. Left and right sides on your tractor and trailer need to provide equal force to complete a safe, even stop. Repetitive uneven stops wear out your tires and other moving parts. This can be dangerous because poor brake balance forces you to pull the steering wheel to compensate.
Causes of Brake Imbalance
Imbalanced brakes happen when the brake drums become glazed - or are too smooth to provide the right friction to stop. But sometimes mismatched brake lining material leads to poor balance, or air fittings and hoses between the valve and chamber are differing sizes or models. Different hose diameters provide uneven forces of air as you apply the brakes.
Often a stuck brake shoe causes your brake balance to be uneven. Corrosion from water or deicing chemicals can make a brake shoe remain in partial contact with the inside of the drum. In addition, automatic slack adjustors that quit working interfere with the ability of your brakes to apply equal force.
Effects of Brake Imbalance
Unbalanced brakes will make your truck pull to one side when you attempt to stop. You may notice increased pulling during certain conditions like high or low speed, light or heavy loads, and during wet driving conditions.
Get Help From a Professional
Increased awareness of problems with brake timing and balance helps you make accurate note of details your technician needs to know when they inspect or repair your brakes.
In addition to paying more attention to how your tractor and trailer handles, use brake parts that share identical performance characteristics to achieve the right balance and timing. Valves should have equal crack pressures, and linings need the same levels of friction.
Clutch & Brake Xchange Inc. can provide the parts you need to maintain proper brake balance and timing. Call us today and ask us how we can provide parts that perform consistently for your tractor and trailer.