1. Improperly installed brake pads. If the brake pads are not installed correctly, they may not be able to move freely in the caliper, causing them to bind and lock up the wheels.
2. Air in the brake lines. When changing the brakes, it is important to bleed the brake lines to remove any air that may have entered the system. If there is air in the brake lines, it can cause the brakes to feel spongy and can lead to the wheels locking up.
3. Faulty master cylinder. The master cylinder is responsible for generating the hydraulic pressure that is used to actuate the brakes. If the master cylinder is faulty, it may not be able to generate enough pressure, which can cause the wheels to lock up.
4. Faulty brake booster. The brake booster is a vacuum-powered device that helps to increase the force applied to the brake pedal. If the brake booster is faulty, it may not be able to provide enough assistance, which can make it difficult to stop the car and can lead to the wheels locking up.
If you are experiencing any problems with your brakes, it is important to have them inspected by a qualified mechanic to determine the cause of the problem and to have it repaired.