What are the causes of brake failure in an air brake system?
4 Answers
The causes of brake failure in an air brake system are: 1. Insufficient brake air pressure; 2. Poor performance of the air compressor; 3. Low air pumping capacity; 4. No air or low pressure in the air reservoir. The working principle of an air brake system is: The air compressor driven by the engine compresses air and inputs it into the air tank through a one-way valve. After cooling in the wet air pipe, the air is divided into two circuits, one leading to the rear brake chamber and the other to the front brake chamber. The components of an air brake system include: air compressor, air dryer, four-line protection valve, main brake control valve, main brake relay valve, front brake chamber, combined brake chamber, parking and emergency brake valve, trailer brake valve, dual-line trailer brake control valve, trailer brake release valve, trailer load adjustment valve, and auxiliary air system components.
I drove heavy trucks for over a decade, and air brake failure was the most dangerous malfunction I ever experienced. The main causes include insufficient air pressure, possibly due to a faulty air compressor or loose belt, which prevents the pressure from reaching normal levels; air leaks are extremely common—aging cracked air lines or loose fittings allow air to escape, resulting in complete brake failure; if the air reservoir's drain valve is clogged or has excessive water buildup, it affects air pressure accumulation; additionally, stuck brake valves or damaged seals can block airflow when braking. I developed a habit of checking the air pressure gauge before every trip—if it's below standard, don't drive. If I ever felt weakened braking on the road, I'd immediately pull over and use the emergency parking brake to stay safe. Regularly replacing desiccants and inspecting pipelines can prevent 90% of these failures.
As an automotive enthusiast, I often pay attention to various system failures. There are several key reasons for pneumatic brake failure: interruption of air supply, such as internal leakage or overheating damage of the compressor; severe air leakage due to corrosion or loosening of the pipeline connections; in addition, excessive system impurities or moisture accumulation can affect valve operation, leading to sluggish braking; if the air reservoir pressure is insufficient or the pressure relief valve malfunctions, it can also directly cause failure. I always say safety comes first—don't push through problems when they arise. For example, if the dashboard warning light comes on, stop and go to the repair shop. Get a comprehensive check-up every year, especially inspecting the condition of the air pump and air hose connections.
I've worked in auto repair shops for many years. The most common cause of pneumatic brake failure is air leakage, often due to worn or ruptured air hoses or deteriorated sealing gaskets at connections. Compressor failures are also frequent, such as broken belts or damaged cylinders. If the air reservoir doesn't drain properly and accumulates too much water, it can cause pressure instability and other issues. Other problems include stuck brake valves or aged rubber cups. I always remind car owners to test the brakes before starting - if anything feels off, get it checked immediately. Routine maintenance like cleaning air filters and inspecting pipelines can significantly reduce failure rates.
