Is low brake fluid normal?

A slight drop as the pads wear is expected — the fluid is displacing into the calipers. A sudden or repeated low level means a leak in the lines, calipers, or master cylinder. Brakes are not the place to wait and see.

What is the difference between DOT 3, 4, and 5?

DOT 3 and DOT 4 are glycol-based and mixable in a pinch, though you should use exactly what the cap says — DOT 4 has a higher boiling point. DOT 5 is silicone-based and never mixes with either; putting it in a glycol system ruins the seals.

How often should brake fluid be changed?

Every 2–3 years regardless of mileage. Glycol fluid absorbs moisture from the air over time, which lowers its boiling point — under hard braking the fluid can boil, turn compressible, and the pedal goes soft. That is pedal fade, and it shows up on the long downhill, not in the driveway.

Can I drive with the brake warning light on?

No. That light means a hydraulic fault or an engaged parking brake — check the parking brake first. If the fluid is low, the pedal feels soft, or the light stays on, tow it. A brake failure costs more than a tow.

How to Check Brake Fluid

About 10 minutesEasy5 steps

Brake fluid is the one fluid you never top off casually — but checking it takes ten minutes and tells you a lot: the level tracks pad wear, and the color tracks age. You can read the reservoir without opening anything. Opening it correctly is where most people go wrong.

Brake fluid strips paint on contact and irritates skin — wipe spills immediately and wash your hands. The brake system is a sealed hydraulic circuit: if the level drops suddenly or the pedal feels soft, do not drive — tow it to a shop. Brake work done wrong fails at the worst possible moment.