Use Ford Heavy-Duty Brake Fluid, Ford specification No. ESA-M6C25-A, or equivalent; do not overfill.
On 1961-67 vans, the master cylinder is located beneath a plate on the driver's side floor pan. To check the fluid level, remove the floor pan cover and unscrew the master cylinder lid. The fluid level should be within 1 / 4 in. (6.35mm) of the top of the reservoir.1969-88 Models
On 1969 and later vans, the master cylinder is located under the hood, on the left side firewall. 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.
- 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.
- On 1969-85 models, pry off the retaining clip or unscrew the hold-down bolt and remove the cap.
- On 1985-88 models, simply unscrew the cap.
- The brake fluid level should be within 1 / 4 in. (6mm) of the top of the reservoir, on cast iron cylinders, or, at the level mark on plastic reservoirs.
- 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.