The (Z Cam) drum brake is designed to reduce installation space and make shoe changes easier.
FEATURES & BENEFITS
1.Internal auto adjuster has no requirement for slack adjuster
2.Adjuster sealed within torque plate/drum protects it from underbody and external environment
3.Sliding shoes for full lining utilization and even drum loading
4.C-spring for shoe return reduces installation space and easier shoe changes  
5.Option for manual adjuster
6.Fabricated shoes for reduced unsprung mass 
7.Smaller installation space compared to S-cam and slack adjuster installations