Silly Question. I have three half used bottles of Brake Fluid that I have had for about 5 years. Would they still be good or do they 'break' down over the years if not used? thanks
Brake fluid is hydrophilic and attracts water, the bane of brake systems. Don't use for brakes. Can be used as a paint remover.
That may be true chemically, but I wonder if it's reality. Can it attract water if the caps were tight on the containers? I don't think there is much difference between the fluid sitting in the container on a shelf and sitting in the brake system. I would use it.
It's true- brake fluid will attract water while sitting in a bottle, or sitting in your car's brake system. Many manufacturers recommend flushing your the brake fluid in your car for exactly this reason. Water will be drawn into the system even through the closed cap of the brake fluid reservoir, or the seals on the calipers or wheel cylinders. That said, I might use what the OP has in a pinch, but it's not that expensive so I'd probably just trash it and buy a new bottle. Small bottles are better unless you are doing a big brake fluid flush and need a Qt or more.