When the Dongfeng Nissan Sima emits noise upon pressing the brake at startup, this could be linked to rust or hard spots on the brake disc, which typically occurs during the initial driving phase and may improve after traveling a short distance.
Additionally, the suspension system or load-bearing components may generate abnormal noises, especially when rubber parts harden, with improvements noted after the vehicle warms up.
Brake cylinder malfunctions are another potential cause; thus, it's advised to check the brake cylinder's condition and visit a dealership for inspection. If noise persists, the first step is to verify the brake resistance is normal. Poor brake caliper reset can result in prolonged friction between the brake disc and brake pad, producing unusual sounds.
It's also crucial to check for foreign objects between the brake discs, especially in new vehicles, and to ensure that the brake discs are correctly slotted to avoid localized friction that may lead to noise. If the brake discs are not an issue, the hardness of the brake pads or the correct installation of the silencer should be examined.
High-frequency sharp sounds may arise from resonance when the vibration frequencies of the brake disc and pads align. For caliper checks, ensure that the guide lubrication is smooth, the piston oil seal is intact, and all noise-dampening clips and brake pads are correctly installed and compatible to prevent noise due to excessive wear.