{"id":3554,"date":"2026-09-29T05:43:50","date_gmt":"2026-09-29T05:43:50","guid":{"rendered":"https:\/\/shop.autoboss.com\/?post_type=product&#038;p=3554"},"modified":"2026-10-09T08:20:31","modified_gmt":"2026-10-09T08:20:31","slug":"autool-as502-car-brake-fluid-tester-brake-fluid-moisture-tester","status":"publish","type":"product","link":"https:\/\/autoboss.com\/de\/product\/autool-as502-car-brake-fluid-tester-brake-fluid-moisture-tester\/","title":{"rendered":"AUTOOL AS502 Moisture Brake Fluid Tester for DOT3\/DOT4\/DOT5.1"},"content":{"rendered":"<div class=\"abd-pd\" data-abd-version=\"1\">\n<header class=\"abd-hero\">\n<h3>Screen Brake Fluid Moisture Straight From the Reservoir<\/h3>\n<p class=\"abd-lead\">Dip the AS502&#8217;s flexible probe into the reservoir and read the water content with an OK, warning or replace indicator. Normal mode covers DOT3, DOT4 and DOT5.1; expert mode adds references for selected DOT4 brands. Brake fluid only.<\/p>\n<ul class=\"abd-facts\">\n<li>DOT3 \/ DOT4 \/ DOT5.1<\/li>\n<li>Normal + Expert Modes<\/li>\n<li>260 mm Flexible Probe<\/li>\n<li>2.8-Inch Backlit LCD<\/li>\n<li>4 \u00d7 AAA Power<\/li>\n<\/ul>\n<\/header>\n<section class=\"abd-sec\" id=\"abd-features\">\n<h4>Hauptmerkmale<\/h4>\n<ol class=\"abd-features\">\n<li>\n<h5>Water-Content Screening<\/h5>\n<p>Measures the water percentage in brake fluid for quick condition checks. It does not generate or measure hydraulic brake pressure.<\/p>\n<\/li>\n<li>\n<h5>Normal and Expert Modes<\/h5>\n<p>Choose a standard fluid type, or switch to expert mode for more targeted selection by DOT4 brand.<\/p>\n<\/li>\n<li>\n<h5>Reservoir-Reach Probe<\/h5>\n<p>The gooseneck probe bends into the reservoir; its stainless steel outer layer resists oil, oxidation and corrosion.<\/p>\n<\/li>\n<li>\n<h5>Clear Status Indicators<\/h5>\n<p>OK means the water content is good, ! is a warning and \u00d7 suggests replacement, shown beside the percentage.<\/p>\n<\/li>\n<li>\n<h5>Single-Handed Use<\/h5>\n<p>A silicone grip and handheld button layout let you test with one hand.<\/p>\n<\/li>\n<li>\n<h5>Battery Saving<\/h5>\n<p>Switches itself off when left idle.<\/p>\n<\/li>\n<\/ol>\n<\/section>\n<section class=\"abd-sec\" id=\"abd-compare\">\n<h4>AS502 vs AS501<\/h4>\n<div class=\"abd-table-wrap\">\n<table class=\"abd-table abd-compare\">\n<thead>\n<tr>\n<th scope=\"col\"><\/th>\n<th scope=\"col\" class=\"is-current\">AS502<\/th>\n<th scope=\"col\">AS501<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<th scope=\"row\">Display<\/th>\n<td class=\"is-current\">2.8-inch backlit<\/td>\n<td>1.8-inch backlit<\/td>\n<\/tr>\n<tr>\n<th scope=\"row\">Test modes<\/th>\n<td class=\"is-current\">Normal \/ Expert<\/td>\n<td>Normal<\/td>\n<\/tr>\n<tr>\n<th scope=\"row\">Normal-mode fluids<\/th>\n<td class=\"is-current\">DOT3, DOT4, DOT5.1<\/td>\n<td>ENV-4, ENV-6, DOT3, DOT4, DOT5, DOT5.1<\/td>\n<\/tr>\n<tr>\n<th scope=\"row\">Power supply<\/th>\n<td class=\"is-current\">6 V<\/td>\n<td>3 V<\/td>\n<\/tr>\n<tr>\n<th scope=\"row\">Probe hose material<\/th>\n<td class=\"is-current\">304 stainless steel<\/td>\n<td>Iron oxide<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/section>\n<section class=\"abd-sec\" id=\"abd-box\">\n<h4>What&#8217;s in the Box<\/h4>\n<ul class=\"abd-box\">\n<li>AS502 brake fluid tester with flexible probe<\/li>\n<li>Bedienungsanleitung<\/li>\n<\/ul>\n<figure class=\"abd-fig\"><img decoding=\"async\" src=\"https:\/\/autoboss.com\/wp-content\/uploads\/autool-catalog\/media\/577205a2dc6fc3a8a29eaefd.webp\" alt=\"AUTOOL AS502 brake fluid tester with its retail box and user manual\" width=\"1200\" height=\"1200\" loading=\"lazy\"><figcaption>AS502 tester, retail box and user manual.<\/figcaption><\/figure>\n<\/section>\n<section class=\"abd-sec\" id=\"abd-use\">\n<h4>Anwendung<\/h4>\n<ol class=\"abd-steps\">\n<li><b>Install batteries<\/b><span>Open the rear cover, insert four AAA batteries with correct polarity and close the cover securely.<\/span><\/li>\n<li><b>Power on<\/b><span>Hold the power button for more than 2 seconds.<\/span><\/li>\n<li><b>Clean the probe<\/b><span>Wipe the probe before each measurement so residue does not affect the result.<\/span><\/li>\n<li><b>Open the reservoir<\/b><span>Remove the brake fluid reservoir cap.<\/span><\/li>\n<li><b>Select the fluid<\/b><span>Press the selection button to choose DOT3, DOT4, DOT5.1 or an expert-mode DOT4 brand.<\/span><\/li>\n<li><b>Immerse and test<\/b><span>Submerge the probe, press the test button and read the water percentage and status.<\/span><\/li>\n<\/ol>\n<p class=\"abd-note\">Modes, result interpretation and troubleshooting: <a href=\"https:\/\/autoboss.com\/wp-content\/uploads\/autool-catalog\/media\/d6281d5ff07505c2e4a32550.pdf\" target=\"_blank\" rel=\"noopener\">AS502 user manual (PDF)<\/a>.<\/p>\n<\/section>\n<section class=\"abd-sec\" id=\"abd-notes\">\n<h4>Good to Know<\/h4>\n<div class=\"abd-notes\">\n<div class=\"abd-note-group is-caution\">\n<h5><span class=\"abd-tag\">Caution<\/span><\/h5>\n<ul>\n<li>For brake fluid only; it is not an engine oil, transmission fluid or power steering fluid tester.<\/li>\n<li>Batteries may not be included; confirm with your package before ordering.<\/li>\n<\/ul>\n<\/div>\n<div class=\"abd-note-group is-care\">\n<h5><span class=\"abd-tag\">Care<\/span><\/h5>\n<ul>\n<li>The reading is a moisture screening, not a standardized wet boiling-point result; apply it with the vehicle&#8217;s service criteria.<\/li>\n<li>For routine maintenance, checking brake fluid around every 40,000 km is suggested, depending on vehicle condition.<\/li>\n<li>Wipe the probe clean after use and leave no fluid residue on it.<\/li>\n<li>For long storage, remove all batteries and keep the tester dry at room temperature.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/section>\n<\/div>","protected":false},"excerpt":{"rendered":"<ul>\n<li><strong>DOT3 \/ DOT4 \/ DOT5.1:<\/strong> Screen water content in supported DOT3, DOT4, and DOT5.1 brake fluids.<\/li>\n<li><strong>Normal + Expert Modes:<\/strong> Use standard fluid-type testing or select Expert mode for supported DOT4 brand references.<\/li>\n<li><strong>260 mm Flexible Probe:<\/strong> Reach brake-fluid reservoirs with the flexible gooseneck probe.<\/li>\n<li><strong>Water + Status Display:<\/strong> View water content with OK, warning, or suggested-replacement indicators on the 2.8-inch backlit screen.<\/li>\n<\/ul>","protected":false},"featured_media":12437,"comment_status":"open","ping_status":"closed","template":"","meta":{"_gspb_post_css":""},"product_brand":[128],"product_cat":[62,99],"product_tag":[137,138],"class_list":["post-3554","product","type-product","status-publish","has-post-thumbnail","product_brand-autool","product_cat-best-selling-products","product_cat-fluid-testers","product_tag-best-brake-fluid-tester","product_tag-brake-fluid-tester","first","instock","shipping-taxable","purchasable","product-type-variable"],"_links":{"self":[{"href":"https:\/\/autoboss.com\/de\/wp-json\/wp\/v2\/product\/3554","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/autoboss.com\/de\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/autoboss.com\/de\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/autoboss.com\/de\/wp-json\/wp\/v2\/comments?post=3554"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/autoboss.com\/de\/wp-json\/wp\/v2\/media\/12437"}],"wp:attachment":[{"href":"https:\/\/autoboss.com\/de\/wp-json\/wp\/v2\/media?parent=3554"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/autoboss.com\/de\/wp-json\/wp\/v2\/product_brand?post=3554"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/autoboss.com\/de\/wp-json\/wp\/v2\/product_cat?post=3554"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/autoboss.com\/de\/wp-json\/wp\/v2\/product_tag?post=3554"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}