Brake basics
No matter the type of braking system you choose, maintenance is essential

By Paul Abelson, senior technical editor

If you value your safety and that of others, taking care of your brakes has to be a top maintenance priority. Brakes give you the control you need and keep you out of trouble.

Brakes can’t do that unless they’re properly engineered and in top condition. While great strides have been made to minimize maintenance requirements in recent years, brakes still require periodic care. That starts with selecting the best components for your brakes based on the way you’ll be using them. Then it’s up to you to maintain them regularly and properly.

For effective braking, components must be in top working order. Brakes can lose stopping power if linings are contaminated. If oil or grease has leaked through seals and gotten on the lining, brakes cannot generate needed friction to stop the truck effectively.

According to the Commercial Vehicle Safety Alliance, which determines out-of-service criteria, evidence of oil seepage onto or out of the brake lining or drum interface is an out-of-service condition. Regular inspection of drums and linings will identify that and other out-of-service conditions.

“Rust jacking” describes a condition caused by salts, brines and chemicals used for highway snow and ice control. When steel brake shoes rust, iron combines with oxygen atoms. That increases the volume of the shoe, building pressure under the brake lining. Since organic linings are weaker than steel shoes, the linings crack from the pressure. Cracked linings are an out-of-service condition.

Powder-coated brake shoe tables from reputable suppliers resist rusting, especially with reconditioned shoes. There are many instances of bargain or counterfeit brake linings and shoes failing under North American operating conditions. Saving money is important, but never at the expense of brake quality.

Excessive localized heat can crack brake drums. Drivers who are easily distracted and suddenly realize they need to brake hard, and do so repeatedly, may have cracked drums. I have personally seen the results of a broken drum section being thrown from a truck. The 10-pound section bounced across the Interstate and crashed through the windshield of a car going in the opposite direction. A passenger died as a result.

Cracks start small, growing as stresses are repeated. That’s why regular inspection is so critical; in this case, it’s truly a matter of life and death.

Ever since self-adjusting brake adjusters became required equipment back in the 1980s, more brakes have been in better adjustment. But there is still a need to maintain these automatic slack adjusters. They should be inspected and greased at every preventive maintenance interval. There are four types of slack adjusters, each with its own adjustment design. LL

July Digital Edition