How to Use Air Brakes?
2 Answers
Air brakes are used by applying intermittent braking, which means pressing and releasing the pedal quickly, then pressing and releasing again until the vehicle comes to a complete stop. It is particularly important to press the pedal quickly. Additional relevant information is as follows: 1. The air brake system consists of a brake control mechanism, dual-circuit brake mechanism, central disc brake mechanism, brake assembly, and air compressor. 2. Working principle: The air pump, driven by the engine, compresses air into high-pressure gas stored in the air reservoir. One of the air reservoirs is connected to the master brake cylinder via pipelines. The master brake cylinder is divided into upper and lower chambers, with the upper chamber controlling the rear wheels and the lower chamber controlling the front wheels. When the driver presses the brake pedal, the upper chamber opens first, allowing high-pressure gas from the air reservoir to pass through the relay valve, pushing out the control piston of the relay valve. At this point, gas from another air reservoir connects to the relay valve and the two rear master brake cylinders. The push rod of the brake cylinder moves forward, rotating the cam at an angle through adjustment. The cam is eccentric, and as it rotates, it expands the brake shoes to create friction with the brake drum, achieving the braking effect.
As a beginner driving large vehicles, it took me some time to master the air brake system. My instructor advised that after starting the vehicle, I should wait patiently for the air pressure gauge to show 7-8 kg or more before moving off, otherwise the brakes might fail. When pressing the pedal, do it gently—don’t stomp like drumming, or the vehicle could lose control. Releasing the brake should also be smooth, allowing air to release slowly for a steady stop. I often practiced on downhill sections, using low gears to control speed and reduce reliance on air brakes to avoid overheating and system damage. Before every trip, I check if the air pressure is stable (confirmed by the green dashboard light); if pressure drops rapidly, inspect pipes or connectors for leaks immediately. It took me weeks to get the hang of it—the core lies in patience and anticipation, with safety as the top priority, because trucks carry heavy loads where even minor risks can lead to severe consequences.
