Fill the clutch fluid reservoir with brake fluid that meets DOT 3 or DOT 4 specifications.
See Figure 1
The clutch system in the Aerostar does not have free-play. It is automatically self-adjusting and should not require any routine service throughout the life of the clutch. The fluid level in the clutch reservoir will slowly increase as the clutch wears. As long as the fluid is visible at or above the step in the translucent reservoir body, top-off is not recommended and should be avoided. This will help prevent overflow and possible contamination of the fluid while the diaphragm and cap are removed. If it becomes necessary to remove the reservoir cap, thoroughly clean the reservoir cap before removing it to prevent dirt or water from entering the reservoir.