FLUID LEVEL CHECK
See Figures 1, 2, 3 and 4
On forward control models, brake master cylinder is located under the instrument panel, in front of the steering column. On all other models, the master cylinder reservoir is located under the hood, on the left side of the 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 fluid level should be within 1 / 4 in. of the top of the reservoir on both single and dual master cylinders.
If the level of the fluid is less than half the volume of the reservoir, it is advised that you check the brake system for leaks. Leaks in a hydraulic brake system most commonly occur at the wheel cylinders.
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 acts to prevent the loss of brake fluid out of the vented cap and to prevent contamination of the brake fluid by dirt. After filling the master cylinder to the proper level with brake fluid, but before replacing the cap, fold the rubber diaphragm up into the cap, then replace the cap on the reservoir and tighten the retaining bolt or snap the retaining clip into place.