Car Makes a Thud Sound When Starting or Braking?
2 Answers
Possible causes for the car making a thud sound when starting or braking are as follows: 1. The fuel cap cannot be opened, or there is a fault in the chassis suspension components, such as lack of lubrication, wear, deformation, etc. 2. Faults in the chassis steering mechanism components, such as tie rods, upper and lower suspension arms, ball joints, etc. 3. Faults in the front or rear wheel bearings, such as wear, lack of lubrication, or burning out. Additional information: Wear on the brake disc can form deep grooves around the disc. Friction between the brake pads and the edges of these grooves can cause abnormal noises. If the grooves are not particularly deep, the issue can be resolved by grinding the edges of the brake pads to avoid contact with the groove edges. If the grooves are very deep, it is recommended to replace the brake disc. It is generally advised to replace the brake disc once for every two brake pad replacements.
I've been driving for twenty years and have encountered this kind of starting brake clunk several times. The main issue lies with the brake discs and pads, especially after rainy days when the rust on the brake discs acts like glue sticking to the pads, making a clunking sound upon starting, similar to tearing off tape. Another time, the brake caliper was stuck and wouldn't retract when releasing the brake, causing a grinding clunk at the moment of starting. My suggestion is to step on the brake a few times while stationary to remove rust before driving. If the clunking is accompanied by a shaking brake pedal, it's likely that the brake discs are warped and need replacement. Nowadays, I try to avoid using the handbrake when parking, opting instead for the P gear plus bricks to block the tires, which has significantly reduced rust issues.
