FORD LIGHT TRUCK: 1993 AEROSTAR, BRONCO, EXPLORER, F-150-350 SERIES, F-47, RANGER UNRESPONSIVE CLUTCH: AIR ENTRAPPED IN HYDRAULIC SYS
Filed Under (Ford) by admin on 07-01-2011
ISSUE A “soft” unresponsive clutch pedal may be felt or the driver may be unable to release the clutch. This is caused by air entrapped in the clutch hydraulic system. ACTION Use the information in this TSB article in addition to the appropriate bleeding procedure. This article includes detail as well as extra service tips for easier hydraulic clutch bleeding. The clutch hydraulic system for the 1993 model year is new and more difficult to bleed than the previous hydraulic system. Therefore, a different bleeding procedure is required for these vehicles. RANGER, EXPLORER, AEROSTAR The most difficult systems to bleed are on the Ranger, Explorer, Aerostars. NOTE: When installing dry clutch cylinder or tube service parts, do the bench bleed procedure first. BENCH BLEED The compact vehicles are more difficult to bleed because the downward angle of the master cylinder makes it difficult for air to escape up into the reservoir. Therefore, if the master cylinder is removed from the vehicle and bled while held in a vertical orientation (a bench bleed) air can escape much more efficiently. Refer to Fig. 1 . BENCH BLEEDING PROCEDURE (CONCENTRIC SLAVE CYLINDER) 1. Remove master cylinder, line and reservoir from vehicle and assemble with replacement parts required based on initial concern. 2. Hold the master cylinder vertically with the reservoir feed hose in the highest position on the body. See Fig. 1 . 3. Fill the reservoir and extend above the master cylinder and assure the quick connect on the clutch line is below the master cylinder. (Lightly clamp reservoir in a vise). 4. Using a small screwdriver, depress the internal mechanism of the male quick connect coupling to open the valve. See Fig. 1 . 5. Stroke and hold master cylinder pushrod. 6. Close quick connect valve. 7. Release master cylinder pushrod. 8. Fill reservoir. 9. Repeat Steps 4 through 8 four more times. 10. With the master cylinder still being held with the outlet tube and reservoir feed tube ends high, quick connect closed and the reservoir full, proceed as follows: a. Push the pushrod into the body several times quickly to expel any remaining air. b. If it is a remote reservoir, pinch the supply hose with your fingers two or three times to help move air into reservoir. 11. When the movement of the pushrod is .130″ (4mm) or less when stroked in Step 10, reinstall the master cylinder into the vehicle and couple it to the slave cylinder.