FORD 2002 F-550 v.1 - Manual (Page 274)

If you use a brake fluid that is not DOT 3, you will cause
permanent damage to your brakes.
Do not let the reservoir for the master cylinder run dry. This
may cause the brakes to fail.
CLUTCH FLUID (IF EQUIPPED)
Check the clutch fluid level. Refer to the scheduled maintenance guide
for the service interval schedules.
Use only a DOT 3 brake fluid designed to meet Ford specification
ESA-M6C25–A. Refer to Lubricant Specifications in this chapter.
Brake fluid is toxic. If brake fluid contacts the eyes, flush eyes
with running water for 15 minutes. Seek medical if irritation
persists. If taken internally, drink water and induce vomiting. Seek
medical attention immediately.
During normal operation, the fluid level in the clutch reservoir should
remain constant or rise slightly. If the fluid level drops, refill the fluid
level to the step in the reservoir.
Maintenance and specifications
274