Can I use Synthetic Dot 4 brake fluid?

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Feb 11, 2010
Atlantic Canada
Soon I will be needing to do a brake and clutch fluid change on my 2004 Kawasaki Vulcan 1500, so while at Wal-Mart I was looking around at their brake fluid products and noticed they had Prestone Synthetic Dot 4. Now I'm confused about the word synthetic on the Prestone container. Is there a difference between just Dot 4 which is what I used 2 years ago and the Prestone Synthetic Dot 4? I thought synthetic brake fluid was Dot 5
I bought the yellow Prestone dot3/4 bottles at WM too. Because they said synthetic on them. Asked about it on here. I was told that just because they wrote synthetic on the bottle does not mean its any different from the other dot3/4 brake fluids. Guess that means all dot3/4 brake fluid is synthetic. Ididn't know that.
I remember Castrol promoting DOT 4 fluid pretty heavily in the 80's as being "much" better than DOT 3. I have been using the Valvoline and Prestone DOT 4 fluids for 25 years and, honestly, I don't notice a difference between it and DOT 3. Maybe that's because I bleed the brakes and change fluid every 30,000 miles? My fluid is never terribly dark when I change it - usually a light amber color, like Irish whiskey. I, too, was fooled for years by that "synthetic" moniker. Maybe the braking systems on the cars I have serviced are just not that demanding.
What others have just said is true. Personally, if I can get Dot 4 and my car calls for Dot 3 I'd get the Dot 4 if it is close to the same price. It has a higher temp rating from what I remember, so might as well get the better fluid.
So what about Dot 5.1? If I were to change my motorcycle Dot 4 brake fluid to Dot 5.1, would that cause a problem? Or is 5.1 overkill.
Only use the fluid recommended. Don't switch any DOT 3 or 4 system to 5.1 and vice-versa. Dot 4 does have a higher boiling point but it doesn't handle water as well as DOT 3 and will more quickly degrade than DOT3. I personally flush my brake fluid every 2 years so I do use DOT 4. If I never flushed my fluid I would stick with DOT3.
Originally Posted By: GMBoy
Dot 4 does have a higher boiling point but it doesn't handle water as well as DOT 3
Yup. DOT 4's compatiblitaty with DOT 3 depends on who you ask. Not a motorcycle manufacturer but for example Chrysler specifically recommends mix DOT 4 with DOT 3
No good reason to mix 3 and 4. Don't even mix new and old . Use the opportunity to flush with new fresh fluid....your system will thank you......
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