How to Adjust Overly Aggressive Air Brakes?
2 Answers
Air brake adjustment method: First locate the adjustment nut on the rear wheel's slack adjuster. Use a 17-19mm box-end wrench placed on it, then tap it gently with a hammer until properly adjusted - it will automatically return to position. For brake chambers, remember 'left loose, right tight'. After adjustment, use a jack to lift the axle (with no load) until the wheel can be rotated by hand, then tighten completely. Note: Passenger car brakes cannot and don't need adjustment. Cars use hydraulic brake systems where brake fluid decreases as pads wear, but the preset gap between pads and rotors remains constant from factory settings. With proper use and maintenance, no adjustment is required.
I've been working on the brake systems of large trucks and have encountered many cases of overly sensitive braking. If the brake response is too quick, it might be due to insufficient free travel of the brake pedal, typically within a range of 10-15 mm. You can adjust the length of the connecting rod with a wrench to increase the travel, making the pedal feel smoother. Also, check the air pressure tank; the normal range should be 650-800 kPa. If the pressure is too high, loosen the pressure regulator valve by turning it counterclockwise to reduce the pressure. Don't forget to inspect the brake valve—there's an adjustment screw there; loosening it slightly can slow down the response. If the parts are severely worn, they should be replaced. Ignoring this issue can lead to brake lock-up and skidding, which is very dangerous. Therefore, I recommend performing maintenance checks every 5,000 kilometers. If problems are found, avoid handling them yourself recklessly; it's much safer to take it to a professional repair station for a thorough inspection.
