What Causes Low Air Pressure in the Parking Circuit?
2 Answers
Low air pressure in the parking circuit is caused by the vehicle's air reservoir failing to store sufficient compressed air. Here is an introduction to the air reservoir: 1. Introduction: The air reservoir is a gas storage device in the vehicle's braking system. 2. Functions: (1) Energy storage: There are numerous applications for compressed air in trucks, ranging from small devices like air horns to critical systems like brakes. Without an air reservoir, the air output from the compressor alone would be far from sufficient. Therefore, the air reservoir stores the compressed air from the compressor for use during critical moments. (2) Filtration: The air pumped by the compressor stays briefly in the air reservoir. Since water molecules, dust, and oil in the air are heavier than air, they settle at the bottom of the reservoir, allowing it to also function as a filter.
Having driven long-haul trucks for over a decade, I've encountered numerous cases of low parking circuit air pressure. The most common cause is leaks in the air system, such as loose hose connections or aging seals in the brake chambers, leading to gradual pressure loss. The issue becomes more pronounced in winter when cold air is harder to compress, directly affecting parking brake performance. If pressure is insufficient and the brake fails while parked on a slope, the truck could slide and cause an accident. That's why I recommend carrying a portable pressure gauge to monitor the situation at all times. If the low-pressure warning light comes on, pull over as soon as possible to check for leaks. For daily prevention, regularly inspect hoses for cracks and ensure connections are tight, especially on vehicles with frequent start-stop cycles, as they're more prone to wear. Neglecting these small details can lead to costly repairs and dangerous situations.
