3)  Valves:  When you replace the valves in your air brake system, the new valves should have the same crack pressure as those you're replacing. Why? Because replacing a valve with one that has a higher or lower crack pressure than the original valve can result in an unbalanced brake system and unacceptable lining and drum life.

4)  Replacement Linings:  Replace the linings on all four brakes of a tandem axle or at minimum both brakes of a single axle at the same time. Otherwise, you may experience brake balance problems. Plus, not replacing a unit's brake linings at the same time may contribute to uneven wear, reduced lining life, maintenance problems or drum-cracking.  Recommendation: replace brakes as an axle set, and do check the lining condition of the other axles.

5)  Drums:  In the brake drum market, there are two basic types: cast and composite, like the Meritor SteelLite X30. They differ in their abilities to absorb and dissipate heat. Using different weight, sizes or types of drums on the same axle could result in unbalanced braking and improper functioning of the automatic slack adjuster. The result will be poor brake performance due to uneven lining and drum wear.

6)  Cam Heads:   All may look the same, but cam heads vary from one manufacturer to another. Some are engineered to provide constant lift while others promise constant torque. As with any brake component, use the proper replacement cam. Failure to do so can result in an unbalanced brake system and unacceptable lining and drum life.

7)  Cam Rollers:  Are they properly lubricated? The way to lubricate a cam roller is directly in the web roller pocket and not at the cam to roller contact area. If you do this correctly you'll avoid creating flat spots. These flat spots adversely affect the brake adjustment which may result in premature brake wear or reduced braking performance. The best time to change your cam rollers is when you reline. That will save you both time and money.