Why Does the Air Pressure Drop Too Quickly When a Truck Brakes?
3 Answers
The reason why the air pressure drops too quickly when a truck brakes is due to air leakage in the brake master cylinder. This is usually caused by infrequent exhaust of the air reservoir, leading to dirt accumulation inside the air reservoir. When braking, the dirt is pushed into the master cylinder, resulting in air leakage. Below are detailed explanations: 1. Solution: If the vehicle's air reservoir cannot store sufficient compressed air, the air supply from the brake valve is insufficient, there is a leak in the brake valve pipeline, or the air passage is blocked, it can cause the air pressure to disappear too quickly during braking. If any of these conditions occur, the vehicle should be sent to an after-sales service or repair shop for maintenance. After repair, the vehicle can be used normally. 2. Air Brake: An air brake is a type of braking system. In automobiles, a series of specialized devices that apply a certain force to specific parts of the vehicle to achieve a certain degree of forced braking are collectively referred to as the braking system.
Last time I drove a truck long-distance, I also encountered this situation. After stepping on the brakes twice, the dashboard warned of insufficient air pressure. This clearly indicates rapid compressed air leakage, so focus on checking the air system. Worn piston seals in the brake chambers can directly cause air leaks, and corroded pipe joints can also leak—listening for sounds can help locate the leak points. If the air reservoir has too much water, it can corrode the tank walls and cause leaks, so remember to drain it daily. If the air compressor isn’t working properly and can’t supply enough air, it will worsen the problem. Additionally, if the intake valve of the brake valve doesn’t close tightly, it will continuously leak air. The most dangerous part is that air leaks increase braking distance. If this happens, quickly downshift to use engine braking and find a safe place to stop for repairs.
Recently, many trucks have experienced issues with their brake air systems, with rapid air pressure drop being a common problem. Abnormal retraction of the brake chamber push rod can cause continuous air leakage from the chamber. Pipe joints, especially metal ones, are prone to corrosion and air leaks. A stuck drain valve on the air reservoir can lead to rust perforation and air leakage. A loose air compressor belt causing slippage results in insufficient air production. Another easily overlooked issue is the failure of the four-circuit protection valve, which can cause air pressure to leak through the faulty circuit. These problems, if occurring individually, might still allow the vehicle to operate, but if two or three issues arise simultaneously, it can lead to weak brakes at best or complete brake failure at worst. Repairing these issues isn't overly complicated, but a systematic inspection of the entire air system is essential.
