STOP - Important Notice

The clutch master cylinder housing can fracture, or seals can be blown out due to excessive hydraulic pressure build up (Figure 1). Fractures in plastic units can begin as a small crack creating a leak, which can later develop into a visible crack in the clutch master cylinder housing. For units made of sheet metal, seals will blow out due to the same high pressure build up. This is often mistakenly diagnosed as a defective master cylinder, especially after repeated failures.

Possible Causes:

• A binding clutch fork / ball stud
• A restricted line to the slave cylinder
• An incorrect clutch / pressure plate requiring a greater force to be exerted.

The most common cause of master cylinder fracture has been reported to be a binding clutch fork, or throw out lever (Figure 2). If the area of contact between the ball stud and the clutch fork is binding, from lack of lubrication, hydraulic pressure in the clutch system can rise substantially. Excessively high pressure can cause the master cylinder to fracture.

If there is a squeaking in the clutch fork or increased pedal resistance, the ball stud and clutch fork should be inspected and lubricated, or replaced.

Important Maintenance Note:

IMPORTANT: Grease should be added "SPARINGLY" to the grease zerk/fitting located on the transmission casing (Figure 3). Excessive grease can contaminate the clutch disc friction surfaces, resulting in slip or chatter and the need to replace the disc. The grease zerk/fitting may not be readily visible on high mileage vehicles and may require cleaning away road dirt to make the fitting visible and serviceable. Lubricate the grease zerk/fitting at 30,000-mile intervals with a hand-operated grease gun only. DO NOT LUBRICATE MORE OFTEN.

Finally, visually inspect the line from the clutch master cylinder to the slave cylinder for any kinks or other damage, which could cause a hydraulic restriction.

Part Number: 9999900