AUTOOL AS502 Brake Fluid Tester – DOT3 DOT4 DOT5.1 Digital

AUTOOL AS502 Digital Brake Fluid Tester

Brake Fluid Water-Content Tester for DOT3, DOT4 & DOT5.1

Brake fluid absorbs moisture over time, which lowers its boiling point and reduces braking performance under heavy use. The AUTOOL AS502 checks the water content of brake fluid in seconds and shows a clear pass, warning or replace result, so you know when a brake fluid flush is due.

Dip the flexible probe into the master cylinder reservoir, select the fluid type and read the water content on the 2.8-inch backlit screen. Expert mode adds settings for 12 popular DOT4 brake fluid brands.

AUTOOL AS502 digital brake fluid tester for DOT3, DOT4 and DOT5.1

Main Features

Water content reading: shows moisture as a percentage, not just a colour or light.
Three-level result: 0–2% pass, 2–3% warning, above 3% replacement suggested.
DOT3, DOT4 and DOT5.1: normal mode covers the common glycol-based brake fluids.
Expert mode: settings for 12 DOT4 brands including MOTUL, ATE, BOSCH, CASTROL, TRW and BREMBO.
Flexible 260 mm probe: gooseneck probe with a 304 stainless steel outer hose reaches into the reservoir.
Result in 10 seconds: quick enough to check on every service.
2.8-inch backlit screen: easy to read in the engine bay.
No test strips: reusable, with no ongoing consumables.
Auto power-off: after 5 minutes of inactivity.

Important Notes

This is a water-content screening test, not a wet boiling-point measurement.
For brake fluid only. Not for engine oil, transmission fluid or power steering fluid.
Select the correct fluid mode, and clean the probe before and after each test.
Runs on 4 × AAA batteries.

Package Includes

1 × AUTOOL AS502 brake fluid tester with flexible probe
1 × User manual

Why Workshops Choose the AS502

Water content %	A clear, numeric reason to recommend a brake fluid flush
Pass / warning / replace result	Easy to explain to customers
Expert mode for 12 DOT4 brands	Matches the fluid actually in the vehicle
10-second test	Fast enough for every service
Flexible stainless probe	Reaches into tight reservoirs
No test strips	No ongoing consumable cost

AUTOOL AS502 brake fluid moisture tester with flexible probe

AUTOOL Fluid Analyzer Comparison

Comparison Table: AUTOOL AS502 Brake Fluid Tester | AUTOOL AS503 Engine Oil Quality Tester

	AUTOOL AS502	AUTOOL AS503

Detection Technology
Detection Technology	Pressure Boost Detection Technology	Optical Probe Technology
Operating Principle	Brake Fluid (Water Content)	Engine Oil (Transmittance)
Test Mode Selection	Normal Mode / Expert Mode	Gasoline Engine / Diesel Engine
Temperature Measurement Range	-	0-85°C (0-185°F)
Test Duration	10s Response	10s Response
Display & Design
Backlit Display Screen	2.8-inch	2.8-inch
Test Cable Length	26cm	80cm
Hose Material	304 Stainless Steel	Teflon
Power & Operation
Power Supply Voltage	6V	6V
Temperature Unit Switching	-	°C/°F
Normal Mode	3 Types: DOT3, DOT4, DOT5.1	-
Boiling Point Reference Value	-	-
	LEARN MORE	LEARN MORE

AUTOOL AS502 Technical Specifications

Application	Brake fluid water-content screening
Supported Fluids	DOT3, DOT4, DOT5.1 (normal mode); 12 DOT4 brands (expert mode)
Reading	Water content %
Result Levels	0–2% pass, 2–3% warning, above 3% replace
Response Time	10 seconds
Display	2.8-inch backlit LCD
Probe	260 mm flexible gooseneck, 304 stainless steel outer hose
Power	4 × AAA 1.5 V batteries (6 V)
Auto Power-Off	After 5 minutes of inactivity
Warranty	3 years main unit, 1 year accessories (manufacturer)

AUTOOL AS502 brake fluid water-content tester with 2.8-inch screen

Delivery

99% of purchases are dispatched from our Melbourne warehouse within 24 hours of payment. Every parcel is shipped with Australia Post e-Parcel, complete with tracking and signature on delivery.

Need it sooner? Express shipping is also available—check if your postcode is in the Next Day Delivery network.

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