Use only heavy duty brake fluid meeting DOT 3 specifications from a clean, sealed container. Using any other type of fluid may result in severe brake system damage.
See Figures 1 and 2
It should be obvious how important the brake system is to safe operation of your vehicle. The brake fluid is key to the proper operation of your vehicle. Low levels of fluid indicate a need for service (there may be a leak in the system or the brake pads may just be worn and in need of replacement). In any case, the brake fluid level should be inspected at least during every oil change, but more often is desirable. Every time you open the hood is a good time to glance at the master cylinder reservoir.
To check the fluid level on most vehicles covered by this information, remove the master cylinder reservoir cap and diaphragm (if applicable) and check the level against the markings on the inside of the reservoir.
When making additions of brake fluid, use only fresh, uncontaminated brake fluid which meets or exceeds DOT-3 standards. Be careful not to spill any brake fluid on painted surfaces, as it will quickly eat the paint. Do not allow the brake fluid container or the master cylinder to remain open any longer than necessary; brake fluid absorbs moisture from the air, reducing the fluid's effectiveness and causing corrosion in the lines.