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2026. 6. 30. 작업

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Mixing DOT 4 with DOT 4 synthetic

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The information & links posted by Paulster2 offer excellent explanation of what the various types of brake fluid are. There are a few grade : DOT3 DOT4 DOT5 DOT5.1 The difference between them is a specificed standard regarding the boiling temperature, which rises as the DOT number rises, and amount of water absorption. There are based on two materials: Glycol based ("traditional" brake fluid) and Silicone based. DOT5 is exclusively silicone based because only silicone meets the criteria specified by the DOT5 standard. As regards mixing them: Generally this is a bad idea, but the main thing warned against is mixing Silicone based fluid with Glycol. This thranslates to not mixing DOT 5 with any other DOT standard fluid. However mixing for example Glycol DOT3 with Glycol DOT4 would give unpredictable performance. Nowhere have I seen anything saying "this is ok". I suspect the reason is that a mixture of formulations may give an unproven boiling temperature. One apparent red herring is