What Causes Brake Shudder at High Speeds?
2 Answers
High-speed brake shudder is caused by uneven brake disc surfaces or excessive radial runout. Below are detailed explanations and solutions: 1. Body Shudder: First, check the vacuum tube connected to the engine to confirm whether it was accidentally dislodged during an oil change or other maintenance, causing a mixture leak. Second, verify whether the vehicle's battery was disconnected during maintenance, affecting the engine throttle. 2. Steering Wheel Shudder: If the brake disc's lateral runout exceeds 0.05 mm, the brake pedal will exhibit slight vibrations when braking at high speeds. These vibrations can transfer through the steering system to the steering wheel, causing it to shake left and right. 3. Tire Pressure: Either overinflation or underinflation can cause issues. Overinflated tires worsen body vibrations at higher speeds, while underinflated tires lead to unstable handling and veering.
Does the steering wheel shake violently when braking at high speed? This kind of high-speed braking vibration is 90% likely caused by brake disc issues. I just encountered this situation last month—after descending a slope at 4th gear, the brake pedal started dancing. Later, inspection revealed a 0.15mm flatness deviation in the front brake discs. The main reason is prolonged high-load braking causing localized overheating and deformation of the brake discs, similar to how a frying pan warps when heated unevenly. Modified cars are more prone to this issue, especially when high-performance brake pads are installed without upgrading the brake discs. Uneven disc wear or rust on the disc surface can also cause this. It's recommended to visit a shop and use a dial indicator to measure the thickness variation of the brake discs. If it exceeds 0.05mm, consider resurfacing or replacing them—after all, the braking system is not something to take lightly.
