Brake Fluids

Check your vehicle owner's manual for the manufacturer-specified fluid type (commonly DOT 3, DOT 4, DOT 5.1 or silicone DOT 5); match the DOT rating and viscosity recommendations and never mix glycol-based fluids (DOT 3/4/5.1) with silicone DOT 5

DOT ratings indicate minimum boiling points and base chemistry: DOT 3, 4 and 5.1 are glycol-based with increasing wet/dry boiling points, while DOT 5 is silicone-based with different properties; choose a rating that meets or exceeds the vehicle manufacturer's requirement for performance and safety

Most manufacturers recommend changing glycol-based brake fluid every 1–2 years or when moisture content and performance degrade; check service intervals in your manual and monitor for spongy pedal, which can indicate moisture contamination

Higher-priced fluids often offer higher boiling points and better thermal stability useful for performance or towing, but for routine daily driving, a mid-range DOT-compliant fluid that meets your vehicle's spec is typically sufficient

Topping off can temporarily restore level but does not remove water or contaminants; a full flush is recommended when fluid is contaminated, discolored, or past the recommended service interval

Mixing different brands of the same glycol-based DOT rating is generally acceptable because they share base chemistry, but avoid mixing different DOT chemistries (e.g., DOT 5 with DOT 4) and follow OEM guidance

Store brake fluid in a tightly sealed, labeled container away from moisture and heat; avoid skin and paint contact, clean spills immediately, and dispose of used fluid per local hazardous-waste regulations