Look also for drips under these units. Here, bad oil seals are a common source of leaks. The major concern is water contamination, since water can enter through a bad seal. If you often drive through mud and water, pay special attention to the color of any drip. If it looks like chocolate milk, water has contaminated the fluid.
Brake fluid is clear and slightly oily, with a medicinal smell.
Leaks may develop in the master cylinder, wheel cylinder, or hydraulic lines and may be caused by loose connections or damaged lines. Look for stains on drum backing plates and disc calipers, hoses, and fittings. Make sure the liquid is brake fluid, not grease from the wheel bearings. Check fluid level in the master cylinder, located near the firewall in the engine compartment. Keep in mind that as the brakes wear, fluid level will drop.