When it comes to brake fluid, not all types are created equal. Two of the most common types you'll encounter are DOT 3 and DOT 4 — but what’s the real difference, and does it matter for your vehicle?

Here’s a clear breakdown so you can choose wisely and protect your brake system’s performance and safety.

1. Boiling Point Differences

• DOT 3: Has a lower boiling point — typically around 401°F (dry) and 284°F (wet).
• DOT 4: Has a higher boiling point — around 446°F (dry) and 311°F (wet).

Why It Matters: Higher boiling points mean better performance under heavy braking, towing, or in extreme heat conditions.

2. Water Absorption Rates

• Both DOT 3 and DOT 4: Are hygroscopic, meaning they absorb moisture from the air over time.
• DOT 4: Absorbs moisture slightly faster than DOT 3 — meaning it may require more frequent changes to maintain peak performance.

3. Vehicle Applications

• DOT 3: Common in older vehicles, standard sedans, and lighter-duty applications where extreme temperatures are less likely.
• DOT 4: Required or recommended in modern vehicles with ABS, performance braking systems, towing capabilities, or heavy-use conditions.

4. Can You Mix DOT 3 and DOT 4?

• Technically Yes: Both are glycol-based fluids and are chemically compatible.
• Not Recommended: Mixing dilutes the higher performance of DOT 4 — and you’ll end up with the lower properties of the two.

5. Best Practices for Brake Fluid Maintenance

• Always Use Manufacturer-Recommended Type: Check your owner’s manual or brake system specs before topping off or flushing.
• Replace Brake Fluid Regularly: Typically every 2–3 years, or sooner if you drive in wet, humid, or extreme conditions.
• Use Fresh Fluid: Never use brake fluid from an opened container that’s been sitting for months — moisture contamination happens quickly.

Final Thought: Match Your Brake Fluid to Your Driving Demands

If you drive hard, tow heavy loads, live in mountainous regions, or use performance braking systems — upgrading to DOT 4 can deliver stronger, more consistent braking power.

And no matter what fluid you use, combining it with Max Advanced Brake Kits gives you complete confidence in every stop, every mile, every time.