Q: How Long Does a Clutch Slave Cylinder Last?

The clutch slave cylinder is part of the hydraulic clutch system that includes the hydraulic slave cylinder, master cylinder and metal, and plastic or rubber lines from the master cylinder to the slave cylinder. The slave cylinder may be mounted either on the outside or inside the transmission bell housing. The external design is mounted on a bracket or bolted directly to the bell housing and has a pushrod that pushes on the clutch release arm. The internal bell housing design is bolted to the transmission over the transmission input shaft housing and has the release bearing mounted on it directly to push on the clutch pressure plate.

Either design of clutch slave cylinders will have internal rubber seals for keeping the fluid and pressure in the system and exterior dust seals to keep dirt, debris, and water from getting into the internal seals. The clutch hydraulic fluid should be replaced on a scheduled maintenance interval as recommended by the manufacturer. If a vehicle manufacturer does not give a recommended service schedule for the clutch fluid but does for the brake fluid, then follow this interval. If no interval is found for servicing it, then I would recommend every 60,000 miles or anytime the clutch is replaced.

On some of the slave cylinders with internal bell housing designs, the slave cylinder should be replaced every time the clutch is replaced or if it is leaking since the transmission has to be removed for servicing the clutch and slave cylinder. The external slave cylinder should be replaced any time it is leaking fluid or the external dust boot has been damaged in any way, which will introduce damaging water, dirt, and debris into the cylinder bore and it will soon fail.

To sum up, the inside and outside style clutch slave cylinders should be replaced anytime they leak, or as a general rule replaced anytime the clutch is replaced. Anytime an incorrect fluid is put in the clutch hydraulic system, it damages the seals and causes the clutch system to become inoperable. You will have to replace the slave and master cylinders and flush out the entire lines if the metal lines are contaminated. Any plastic or rubber lines should be replaced if contaminated.