Can You Recognize Brake Drum Damage?
Despite changes in technology, brake drums are still the most popular choice for delivering reliable stopping power for heavy-duty trucks. One of the major reasons is that drum brakes are less expensive than disc brakes and can last longer, especially if you’re using newer drum brakes that are equipped with more effective friction materials.
In fact, it’s that friction material that provides brake drums with their stopping power. It is also what will eventually wear down or damage even the strongest brake drums.
Brake drum wear is unavoidable over the life of a truck. But in some instances, drum damage can occur prematurely because of imbalances, excessive and extreme brake use, and improper maintenance. Drivers are often the first to identify that a drum is failing. If a driver reports that a truck’s brakes are grinding or squealing, or that they feel a shuddering or vibration in the brake pedal, then it’s time to take a closer look.
A visual inspection can identify specific types of brake drum damage, as well as their underlying causes. Now is always a good time to examine your trucks’ brake drums to identify potential CSA violations. Here are some things to look for:
- Heat checking – Heat checking is a normal sign of wear that’s indicated by hairline cracks on the surface of a brake drum. However, if one or more cracks extends across the drum surface or is at least 0.06 inches wide or 0.12 inches deep, the drum should be replaced.
- Cracking – Cracks are a concern if they extend through the drum wall. These deeper cracks can have several causes, including excessive heating and cooling of the drums during use, setting the parking brake when drums are excessively hot, or drum mishandling. Cracked drums must be replaced immediately.
- A blue surface – Blue drums are caused by extremely high temperatures, brake imbalance, hard stops, dragging brakes or glazed brake linings. Blue drums can continue to be used unless cracks have developed.
- Martensite – Martensite brake drums have dark-colored spots that are hard and raised. Martensite spots can be caused by the use of improper friction materials or improper burnishing techniques, as well as dragging brakes, continued severe brake applications, brake imbalance, or imbalance between the tractor and the trailer. Drums with Martensite spots should be removed and replaced.
- Scoring – Scored brakes have defined grooves on the braking surface. Scoring is typically caused by foreign materials or dust in the rivet holes, loose rivets or bolts, or broken or loose shoe springs. Depending on the amount of scoring, the drum may be resurfaced and reused.
- Polishing effect – With their mirror-like finish, polished drums are a sign that a truck is using improper friction or dragging its brakes. Polishing can be remedied by sanding the drum’s surface with an 80-grit emery cloth.
- Grease – Grease on the braking surface is the sign of a bad or leaking grease seal or improper lubrication of brake components. After the grease is removed and the leak is fixed, the drums can be reused.
Trust Road Choice® for Durability
While some types of brake drum damage can be repaired, often the better and safer choice is to replace the old drum with a new one.
Road Choice® brake drums are available for most popular front, rear, trailer and reduced-stopping distance (RSD) configurations. Each Road Choice brake drum is:
- Manufactured to industry standards and specifications to ensure superior quality
- Composed of high-strength metals, including carbon, manganese, phosphorus, sulphur and silicon
- Able to provide greater wear resistance with a tensile strength of 35,000 psi
- Extremely durable, with a Brinell hardness of 207-255 as specified by the Society of Automotive Engineers International (SAE)
You can count on Road Choice for top-quality, high-performing brake drums at a competitive price.