What are the reasons for car shaking during braking?

[VanessaRose]

Car shaking during braking can be caused by: 1. Worn brake pads; 2. Unbalanced wheel alignment; 3. Deformed wheel hubs; 4. Vehicle ABS system intervention; 5. Dislodged tie rod ends or loose fixing bolts of the lower control arm, etc. The braking system is a crucial component for daily driving safety, and any issues with it can significantly impact driving safety. It is recommended that car owners promptly visit a repair station for inspection and maintenance when experiencing brake shaking to prevent traffic accidents caused by brake problems. Additionally, car owners should avoid speeding during daily driving, decelerate in advance when necessary, and refrain from harsh emergency braking.

[MacLevi]

Last time I drove long distance, the steering wheel shook like a phone vibration when braking, so I went for a check immediately. The mechanic said the most common cause is warped brake discs, especially after frequently driving on mountain roads or going through water, which can cause high temperatures and uneven disc surfaces. Uneven wear on brake pads can also damage the discs, and frequent hard braking may lead to hard spots on the disc due to overheating. By the way, if the steering tie rod ball joint is loose or the control arm bushings are cracked, the entire suspension wobbles during braking and transmits the vibration to the steering wheel. Now that it's hot, extra caution is needed. My friend’s car recently had a stuck caliper piston, causing one-side brake pads to overheat. It’s recommended to check the disc runout immediately—if it exceeds 0.05mm, the discs should be resurfaced or replaced.

[VanCarmen]

Over the past decade of repairing cars, I've seen too many vehicles with brake vibration issues. Let me break it down into three levels. The most superficial cause is uncleaned mud on the inner side of the wheel hub, which can be resolved by washing the wheels during a car wash. Looking deeper, when both the steering wheel and brake pedal vibrate, there's an 80% chance the front brake discs are warped; if only the pedal kicks back, then the rear brake discs need inspection. The most troublesome cases involve AWD vehicles that shake during both acceleration and braking, possibly indicating issues with the driveshaft universal joint. I recall an Audi owner who replaced brake discs and pads three times but still had vibration, only to finally discover 1mm of excessive play in the wheel hub bearing.

[Hunger]

When I first got my driver's license, I was also scared by brake shudder. Actually, apart from the commonly mentioned brake disc issues, there's a lesser-known cause—tires! If the tire tread has bulges or the wheel balancing weights fall off, sudden changes in ground contact pressure during braking can cause shudder. Those who've modified their brake calipers should pay attention to whether the pistons aren't resetting properly—my colleague's modified car had one-sided brake drag due to lack of lubrication on the caliper guide pins. Don't overlook routine maintenance: remember to retorque the wheel hub bolts every 20,000 kilometers. Last time at the dealership, when they used a torque wrench to tighten my bolts, they found two bolts were off by 20 Nm.