Why does the air pressure drop after a few brake applications?
2 Answers
First, check if the brake is stuck. Observe whether the air pressure gauge shows a drop. If it does, the rubber cup might be damaged and needs replacement, or the entire wheel cylinder assembly may require changing. If there's no pressure drop, adjust the brake as excessive wheel cylinder clearance can also cause rapid air release. If air leakage is suspected, it's recommended to visit a repair shop for inspection. Brake Air Pressure: Insufficient compressed air storage in the reservoir, inadequate air supply from the brake valve, air leaks in the brake valve pipelines, or blocked air passages can all lead to insufficient compressed air pressure in the braking system during operation. When the driver presses the brake pedal in an air brake system, the brake control valve opens, connecting the passage from the reservoir to the brake chamber. Compressed air from the reservoir flows through the brake control valve into the brake chamber. Sufficient air pressure pushes the brake chamber push rod outward, rotating the brake adjuster arm to turn the cam. The cam's rotation forces the brake shoes to expand and press against the brake drum, thereby braking the wheel. Any of the above issues can reduce the pressure delivered to the brake chamber. Insufficient pressure fails to push the chamber push rod outward, preventing the brake shoes from expanding and pressing against the brake drum to brake the wheel. Air Brake: This is a braking method. In automobiles, a series of specialized devices that apply external force to certain parts of the vehicle to enforce braking to some extent are collectively referred to as the braking system.
When I was driving a truck before, I encountered this situation where the air pressure alarm would go off after a few brake applications. The issue was due to air leakage in the system. Upon inspection, I found that the air hose connectors were aged and loose, the air valve might also be leaking, and the compressor had low air-pumping efficiency, failing to store enough air. The solution was to start the engine and listen for hissing sounds to locate the leak points, then spray soapy water on the connectors to check for bubbles indicating leaks. Safety is no trivial matter; if the air pressure is too low, you must stop and repair it—don't continue driving. This problem is common in older vehicles or those with poor maintenance. Regularly replacing the dryer and inspecting the entire air pressure system can prevent such issues, avoiding breakdowns on the road, which are both troublesome and dangerous.
