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I'm working on my buddy's '05 FXDWG brakes for him. Date manufactured shows "07-04" on the VIN sticker so I'm guessing that means 04/07/2005 since I don't think they'd be working on Independence Day.
Brake reservoir is stamped DOT 5 as expected but when I bled the system this is what I got. Buddy bought the bike back in '05-'06 with 800 on the clock and besides oil changes I don't think much maintenance has been done to it. Can DOT 5 turn that color from age/wear? Shouldn't it be purple? If someone did put DOT 4 in the system at some point, should I flush and get it filled with DOT 5 again? It's a beautiful ride besides needing tires and some minor maintenance and it's only got 21k on it.
Yeah, I've seen it change colors like that after a long time. But I'd still check the fluid using the water test, just to be sure. Water will mix (go into solution) with DOT4 or other glycol based fluids. When you add water to DOT4 and stir it a little the water will mix and not be seen.
If you add water to DOT5 (silicone based) it will not mix and you will continue to see the water bubbles in the brake fluid. Never mix DOT 4 and 5 fluid (glycol with silicone fluids). If the fluids are mixed, or if you want to change from DOT4 to DOT5 on non ABS systems, you would need to completely rebuild the cylinders and flush the lines well. Some say to just replace the lines as it eliminates the issue.
The ability of glycol (alcohol) based brake fluids to absorb water is why they must be flushed annually or when ever the moisture content reaches 3% or greater.
Drop some in water. Dot 5 looks like oil. (YouTube for testing difference)
Originally Posted by pgreer
Yeah, I've seen it change colors like that after a long time. But I'd still check the fluid using the water test, just to be sure. Water will mix (go into solution) with DOT4 or other glycol based fluids. When you add water to DOT4 and stir it a little the water will mix and not be seen.
If you add water to DOT5 (silicone based) it will not mix and you will continue to see the water bubbles in the brake fluid. Never mix DOT 4 and 5 fluid (glycol with silicone fluids). If the fluids are mixed, or if you want to change from DOT4 to DOT5 on non ABS systems, you would need to completely rebuild the cylinders and flush the lines well. Some say to just replace the lines as it eliminates the issue.
The ability of glycol (alcohol) based brake fluids to absorb water is why they must be flushed annually or when ever the moisture content reaches 3% or greater.
Mystery solved. I followed the advice given and the fluid will NOT combine with water, it floats on top or beads, so DOT5 and that's a relief...and I learned something. Thanks guys!!
My '96 Dyna had that color fluid in the brakes. I flushed the system with denatured alcohol, then installed the Dot 5. DO NOT USE Dot 5.1! They aren't interchangeable!
Dot 5 - 4
