How does a pneumatic system differ from hydraulic in braking?

Pneumatic braking systems operate by using compressed air pressure to activate the brakes. This is distinct from hydraulic systems, which utilize incompressible fluid pressure—generally brake fluid—to transmit force to the braking components. The mechanism of compression in pneumatic systems allows for powerful braking force to be distributed across multiple brake components through a network of air lines. This air pressure operates the brake mechanisms effectively, making them well-suited for heavy-duty applications like trucks and buses.

Understanding this distinction between how pneumatic and hydraulic systems generate braking force clarifies the advantages and limitations of each system. Hydraulic systems typically have a more consistent and immediate response, particularly in light vehicles, due to their use of liquid, which does not compress. However, pneumatic systems are advantageous in larger vehicles where air can be easily stored and used, leading to efficient braking performance over larger distances and loads.