Healthy brake fluid should be nearly clear with a yellow tint, which should be pretty close to the color it was in the bottle before you initially poured it into your car’s reservoir.
Examine the color of the brake fluid.
Like we said above, fresh brake fluid should be almost clear with a hint of yellow coloring. If your brake fluid resembles oil, and is a dark brown or black color, then you need a brake fluid flush and replacement.
Be aware that as the moisture content of the fluid increases, the boiling point decreases. New glycol-based fluid (DOT 3, DOT 4, DOT 5.1) is a translucent yellow color. In fact, it almost looks clear when you pour it out of the bottle. Fresh DOT 5 brake fluid is a purple color.
Old brake fluid tends to be muddy brown/black and looks like used motor oil. Like motor oil, brake fluid gets darker the more grime and debris it picks up. The dirtier it gets, the less effective it becomes. Dark brake fluid is a good sign you should consider a brake fluid flush.
Black or brown brake fluid is a sign that it is heavily contaminated. When this is the case, the brake system’s ability to build pressure s diminished, and the performance of the brakes can be affected. Contaminated brake fluid can make the brakes become spongy.
Brake fluid is usually a light, clear color. If it’s not clean or transparent, then your brake fluid is dirty and needs changing. The reservoir should have a label that says, “full line.” If the brake liquid falls below that line, it’s a sign your need to change your brake fluid or top it off.
Normal Aging Gone to the Extreme: The most common reason that brake fluid appears brown or black is that normal ageing has gone unchecked (you haven’t had the fluid changed in too long). Contaminants collect in the fluid, darkening the colour and reducing its ability to work.
The reason why you don’t want to run with black brake fluid is that the color indicates that there’s probably a fair bit of contaminants and moisture that have been absorbed into the fluid.
Are DOT 3 and DOT 4 Brake Fluid Compatible? Yes. DOT 3 brake fluid is compatible with DOT 4 brake fluid. However, DOT 4 offers a higher boiling point.
Can you mix Dot 3 and Dot 4 Brake Fluid? Yes, Dot 3 and Dot 4 brake fluid can be mixed. It’s because both these are glycol-based brake fluids, which means that they are compatible with each other. If your car has Dot 4 from the factory, it’s not recommended to fill it with Dot 3, though; but the other way is fine.
The brake fluid also grips moisture thus reducing its ERPB (boiling point). The fluid can affect the paint of the vehicle, so you need to handle it with care. The color of the DOT 4 brake fluid is almost mineral clear with a little composition of yellow. It is compatible with DOT 3 and DOT 5.1.
Another important one is brake fluid. Like other fluids, your brake fluid will deteriorate over time and eventually need to be replaced with a brake system flush. If you’ve noticed that your brake fluid appears black or brown, it’s well past time for a service.
Most manufacturers recommend changing brake fluid at least every two years. Because it plays a crucial role in keeping you safe and because it’s not easy to tell how often you should change brake fluid, it is advisable to carry out a visual inspection of the fluid much more frequently.
The brake fluid is green because the factory assembly grease used in the assembly of the master cylinder is green!
If your brake fluid color is dark, it needs to be flushed and replaced with fresh fluid that’s compatible with your vehicle. Brake fluid color usually goes darker as it gets old. This mainly occurs because brake fluids are hygroscopic, which means they are designed to absorb water.
DOT-3 BRAKE FLUID BLUE. Atlantic DOT 3 Brake Fluid is a premium, high boiling polyglycol-based fluid formulated for use in a wide range of ABS, disc drum brake and hydraulic clutch applications.
Brake fluid runs the brown color spectrum of amber to black depending on its age and condition. Brake fluid just put into the braking system is new and will be amber or light brown. As the brake fluid ages, it turns dark brown to black. Some brake fluid is also yellow.