What Causes Motorcycle Brakes Not to Rebound?
2 Answers
Motorcycle brakes not rebounding can be caused by rust on the brake lever shaft, rust on the brake cable, or water in the brake fluid. The specific reasons and solutions are as follows: Water in the brake fluid: Disc brakes consist of a brake disc connected to the wheel and a brake caliper on the edge of the disc. During braking, high-pressure brake fluid pushes the brake pads to clamp the disc, achieving the braking effect. If there is water in the brake fluid, the pump piston may rust. Completely disassemble the brake pump, push the piston to its longest position, and evenly spray WD40 or other rust removers. Afterward, use a hard plastic scraper to thoroughly remove rust and sludge from the piston. Do not use ultra-fine metallographic sandpaper for complete removal. Spray WD40 again, then push the piston back into the brake pump. Push it back and forth a few times to make it much smoother. Reinstall the brake and avoid full impact. Rust on the brake lever shaft or brake cable: Both issues can be addressed by using sandpaper to remove the rust or by replacing the affected components.
As someone who frequently tinkers with motorcycles, I have to say that brake failure to retract mostly occurs in the hydraulic system. If the brake fluid is aged or contains air bubbles, the pistons in the caliper can easily get stuck and fail to retract; or if the fluid level is too low, the system may malfunction. Additionally, internal rust or sludge buildup in the caliper can also lock the pistons. Another common cause is when the springs fail and can't push the brake pads away. Once, while helping someone fix their bike, I found that the owner hadn't changed the fluid for a year, leading to severe corrosion. This is no small matter—failure to retract means the brakes are constantly applying pressure, wearing down the pads and potentially overheating the wheel hub, which could lead to sudden loss of control while riding. I recommend checking the fluid quality and cleaning the components, replacing the fluid if necessary. Don't delay—safety comes first. Before attempting a DIY fix, make sure you have all the necessary tools, or better yet, consult a professional.
