Trailer braking response slows down, prioritize checking which pneumatic components

Many overseas heavy truck fleets encounter common driving hazards: the tractor brakes are sensitive, but the trailer brakes react slowly and delay, especially when heavy loads go downhill. Most drivers mistakenly believe that it is caused by brake pad wear, but in fact, more than 90% of the faults are due to aging, blockage, and abnormal pressure relief of pneumatic components. Trailer braking delay can significantly lengthen the braking distance, which can easily lead to rear end collisions and side slip accidents. Blindly replacing brake pads cannot solve the problem. Mastering the low-cost air circuit inspection sequence can quickly locate the root cause and efficiently restore braking performance. Firstly, prioritize checking the emergency relay valve of the trailer, which is the core component of braking delay. The relay valve is responsible for quickly distributing and delivering brake air pressure, and is the "center" of trailer braking. After long-term use, the internal valve core of the valve body may become stuck, the spring may become fatigued, and the intake filter may become clogged, resulting in delayed air pressure delivery, slow braking, and slow return. At the same time, the aging and leakage of the valve body sealing ring can cause insufficient air pressure and weak braking. This is the primary cause of slow braking response in trailers. When troubleshooting, priority should be given to cleaning the valve body filter, checking for air leaks, and replacing aging components directly.
Focus on inspecting the trailer's air storage cylinder and drain valve. In overseas construction sites and rainy and high humidity conditions, compressed air has a high water content, and long-term accumulated water will accumulate inside the air storage cylinder, occupying the air path space and compressed air pressure volume, resulting in slow response of brake air supply. Accumulated water can also corrode valve bodies and pipelines, exacerbating air circuit failures. Regularly open the drainage valve to drain accumulated water in daily life, check whether the drainage valve is stuck or the seal is ineffective, and prevent brake lag caused by water in the air circuit and unstable air pressure.
Check the air pipeline, joints, and dust filter element. Long term jolting and vibration of trailers can cause aging and flattening of air pipes, collapse of pipelines, and slight air leakage due to loose joints, resulting in loss of air pressure transmission and a decrease in braking response speed. At the same time, the small filter element of the trailer's intake is prone to adsorbing dust and impurities, and long-term failure to clean it can cause air blockage and poor gas supply. During operation and maintenance, check the smoothness of the pipeline and the sealing of the joints one by one, clean the dust accumulation of the filter element, replace the cracked and aged air pipe, and repair the fault without replacing large parts.
Check the brake cylinder and spring brake chamber. Aging of the air chamber diaphragm, slight air leakage, and sticking of the push rod can cause the air pressure to be in place but the braking action to be delayed and weak. Dust and rust accumulation on the push rod of some vehicles' air chambers, as well as movement jamming, are also common reasons for slow braking. It is possible to manually test the flexibility of the push rod extension and contraction, check for pressure and air leakage in the air chamber, timely maintain and lubricate or replace damaged parts, and restore the braking response speed. Overall, slowing down trailer braking does not require blind major repairs. Following the troubleshooting sequence of "relay valve → air reservoir → air path filter → brake chamber" can solve most of the faults. Overseas fleets should regularly maintain their air routes, promptly clean up blockages, and replace aging parts. This can not only ensure sensitive and stable braking, but also avoid potential safety hazards and reduce maintenance costs.