Do your brakes feel soft? It’s probably your brake wheel cylinders.
Brake wheel cylinders are mostly found in modern drum brake systems. When the pedal is depressed, the part extends to extends to press the brake shoes against the brake drum and slow the vehicle. As a hydraulic component, the wheel cylinder is subjected to the harsh conditions of braking and can wear out over time. When brake wheel cylinders do go bad, they will usually produce a few symptoms that can alert the driver that they may need to be replaced: