Brake Fluid Moisture Tester – LED Indicator for DOT3, DOT4 & DOT5

Brake Fluid Moisture Tester – LED Indicator for DOT3, DOT4 & DOT5

Brake fluid absorbs moisture over time, and as moisture content rises, the boiling point of the fluid drops — increasing the risk of brake fade under heavy use. This tester gives you an instant moisture reading in seconds using a 5-LED indicator system, so you know exactly when your brake fluid needs changing before it becomes a safety issue.

Compatible with DOT3, DOT4 and DOT5 brake fluids. Battery included.

🔧 Specifications

• Measurement Range: 0% to 4% moisture content
• LED Indicators: 5 LEDs (Green to Red scale)
• Compatible Fluids: DOT3, DOT4, DOT5
• Auto Power-Off: 12 seconds
• Battery: 1.5V AAA (included)
• Certifications: CE and RoHS approved

LED moisture scale

• 🟢 Green only — no moisture detected, fluid is in good condition
• 🟢🟡 Green + Yellow — less than 1% moisture
• 🟢🟡🟡 Green + 2x Yellow — approximately 2% moisture
• 🟢🟡🟡🔴 Green + 2x Yellow + Red — approximately 3%, change recommended
• 🟢🟡🟡🔴🔴 All 5 LEDs — 4% moisture, change brake fluid immediately

Why drivers and mechanics use this tester

• 🛡️ Prevents brake fade — high moisture content lowers the boiling point of brake fluid, increasing fade risk
• ⚡ Instant results — reading in under 1 second, no warm-up required
• 💧 Works on all common brake fluids — DOT3, DOT4 and DOT5 compatible
• 🔋 Battery included — ready to use straight from the box
• 🔄 Auto power-off — shuts down after 12 seconds to preserve battery life
• 📌 CE and RoHS certified — meets safety and environmental standards

How to use

1. Remove the cap from the brake fluid reservoir and the probe cap from the tester
2. Press the power button — the green LED will illuminate
3. Dip the metal probes fully into the brake fluid
4. Wait 1 second and read the LED result against the moisture scale
5. Clean the probe with water after use

Frequently Asked Questions

How often should I test my brake fluid?
Most vehicle manufacturers recommend checking brake fluid condition every 12 months or 20,000 miles. Testing with a moisture tester takes seconds and can be done at every service.

What moisture level means I need to change my brake fluid?
A reading of 3% or above (4 or 5 LEDs illuminated) indicates the fluid should be changed. At 4% moisture, the boiling point has dropped significantly and the fluid should be replaced immediately.

Is this compatible with all vehicles?
It is compatible with any vehicle using DOT3, DOT4 or DOT5 brake fluid, which covers the vast majority of passenger cars, motorcycles and light commercial vehicles.

What is the best way to check if brake fluid needs changing?
A digital moisture tester is the most accurate and quickest method — it measures actual moisture content rather than relying on colour or age, giving a reliable indication of fluid condition regardless of mileage.

📦 Package Contents

• 1 x Brake Fluid Moisture Tester
• 1 x 1.5V AAA Battery