Handling of cars with brake lock after flooding
After the car is flooded, the brake pads expand, the brake pedal is small, leading to the brakes locking.
Therefore, if stopping the car immediately after going through a flooded road, the driver should not pull the handbrake immediately but should brake gently to dry the brake pads before storing in the garage.
The best way to handle this situation is to let the car move forward and backward gently until you hear a loud noise under the tires and brakes, indicating that the car is no longer locked. Then spray some anti-rust solution on the brake discs and gently tap the brake pad assembly.

If you find it cannot be handled, the best way is to take the car to the garage to remove all four wheels, clean and maintain the brake system.
Some other causes of car brakes locking
Brake pad wear
The brake pads, combined with excessive wear or repeated smoothing of the brake disc, make the brake disc thinner than the standard thickness. When braking, the brake piston is pushed beyond its limited stroke, causing the piston or brake disc to not return, but to press tightly against the brake drum or brake disc, causing the brake to lock.
When encountering this situation, the driver can temporarily handle it by removing the wheel and removing the brake drum and drum brake, then using a screwdriver to push the piston back to its original position and taking the car to the garage for handling.
Torn rubber layer protecting brake caliper
With disc brakes, when the rubber layer protecting the brake caliper is torn, dirty water enters and causes rust. When braking, large oil pressure acts on the brake piston, causing the caliper to be pushed out. However, due to the small return force, it cannot overcome the resistance caused by the rusted caliper, leading to brake lock.
At this time, the driver should remove the battery, clean it, and apply grease to fix the brake lock. The piston is rusted or pitted, the cause of the brake lock is similar and the solution is also cleaning or replacing.
Deformed brake disc
Due to external impact on the brake disc, it has caused deformation, causing the brake disc to not rotate evenly but to be reversed. This causes the brake pads to always be in a state of being tightly pressed against the brake disc surface, causing the brake to lock.
The quickest temporary fix is to remove the seized brake pads for repair.