What are the reasons for the failure of the rear wheel brake in a vehicle with air brakes?
2 Answers
There are many reasons for the failure of the rear wheel brake in a vehicle with air brakes, mainly including low air brake pressure, excessive brake clearance, insufficient brake fluid, etc. Low air brake pressure in the vehicle: If the air brake pressure is too low, or if there is a malfunction in the pressure pipeline or air pump, the air brake will be soft, and the vehicle will be unable to stop. In this case, the pressure value of the air brake should be checked, the pressure pipeline should be inspected for leaks or blockages, and repairs should be made promptly. Excessive brake clearance distance in the vehicle: If the vehicle has been used for a long time, the aging of vehicle components can lead to excessive brake clearance, affecting the normal operation of the brake system. In this case, the brake clearance of the vehicle needs to be readjusted to the standard range, and aged components should be replaced in time to prevent safety hazards. Insufficient brake fluid in the vehicle: When there is a lack of brake fluid, it can also affect the normal operation of the brake system, causing the brake to be soft, delayed, or unable to brake. In this case, the brake fluid should be replenished and replaced promptly.
Last time the rear wheel brakes on my truck failed, it really scared me! The inspection revealed that the brake chamber was leaking air, and the air line fitting had aged, causing all the compressed air to leak out. Remember to also check if the slack adjuster spring is broken—mine was broken, which prevented the cam from pushing the brake shoes. Air line blockages are also quite common, especially in the northern winters when the lines freeze and become blocked, which is even more dangerous. If the air pressure gauge shows normal pressure, it might be a fault with the master cylinder valve. Such issues can’t be delayed—pull over immediately and call a tow truck. Fixing it requires removing the entire wheel hub, and without professional tools, it’s simply impossible.
