Failed caliper, wheel cylinder, hose, or line.
the rubber brake line maybe collasped this can happend and not let fluid pass
Power steering pump worn, or low on fluid
A leak in the brake system. Fluid has leaked out and air is now in your lines. This can be from a brake cylinder at wheel or in master cylinder, or even worse a rusted brake line. Check and repair it NOW.
Axel seals leaking grease on the brake shoes. Wheel cylinders leaking brake fluid. To much brake dust in the drums.
IF you have rear wheel drive it may be a grease seal for the rear differential. Otherwise it is probably a wheel cylinder. Check your brake fluid level. GEt this fixed ASAP- Safety concern. Wheel cylinder, brake fluid.. If it's a rear wheel drive vehicle, it may be the axle seal leaking as well. Hello... hello...
You might be out of brake fluid. Our rear wheel cylinder was leaking and ran ours out of fluid and the light came on.
leaky wheel cylinders or calipers
One at each Wheel just below where the Brake fluid line attaches. One or two at the Brake fluid reservoir.
All, master cylinder, brake calipers, and wheel cylinders, must be flushed out. Motor oil causes the seals to swell and lock up brakes.
You have a leak(s). Check main brake lines and brake cylinders at each wheel.
Rebuild the cylinders on that caliper.
They compress the brake fluid and push the brake shoes out against the brake drum stopping the vehicle.