See Figures 1, 2, 3 and 4
The master cylinder reservoir is located under the hood, on the left side firewall. Before removing the master cylinder reservoir cap, make sure the vehicle is resting on level ground and clean all dirt away from the top of the master cylinder. Pry off the retaining clip or unscrew the hold-down bolt and remove the cap. The brake fluid level should be within 1 / 4 " (6mm) of the top of the reservoir.
If the level of the brake fluid is less than half the volume of the reservoir, it is advised that you check the brake system for leaks. Leaks in the hydraulic brake system most commonly occur at the wheel cylinder.
There is a rubber diaphragm in the top of the master cylinder cap. As the fluid level lowers in the reservoir due to normal brake shoe wear or leakage, the diaphragm takes up the space. This is to prevent the loss of brake fluid out the vented cap and contamination by dirt. After filling the master cylinder to the proper level with heavy duty brake fluid, but before replacing the cap, fold the rubber diaphragm up into the cap, then replace the cap in the reservoir and tighten the retaining bolt or snap the retaining clip into place.