Replacing a clutch slave cylinder on a Jeep Wrangler depends entirely on the year it was made. If the Wrangler was made since 1994, the slave cylinder is a permanent part of the assembly with the clutch master cylinder; you must replace this whole assembly. The slave cylinder can be separated on earlier models, so you can remove and replace it individually. Remember that there is a good chance that air will get in the system as you do this.
Raise the Jeep's front end with your floor jack -- an aftermarket jack works much better than the stock one -- and support it on jack stands place under the frame rails.
Open the cap on the clutch master cylinder and siphon the fluid out of the cylinder using a turkey baster or similar siphon tool.
Disconnect the hose connecting the slave cylinder to the master cylinder using a hose clamp tool if the line can be disconnected.
Remove the mounting nuts that fasten the slave cylinder to the clutch housing with your wrench. Remove any fasteners connecting it to the master cylinder and remove the slave cylinder, making sure you don't spill fluid. Proceed to Section 2.
Disengage the hydraulic line from the clips connecting it to the body if you cannot separate the slave cylinder from the rest of the assembly, then remove the lower nut connecting the master cylinder to the firewall on the engine side.
Remove the master cylinder's mounting nut from under the dash in the Jeep and unclip/disconnect the pushrod from the clutch pedal.
Lift and remove the master/slave cylinder assembly from the engine compartment.
Install the master cylinder assembly against the firewall in the engine compartment and connect its lower mounting nut without tightening it all the way. Skip to Step 3 if you are only installing the slave cylinder.
Connect and tighten the mounting nut within the Jeep's driver compartment and reconnect the pushrod, then tighten the engine side nut the rest of the way. Proceed to Step 4.
Connect the replacement slave cylinder to the master cylinder and the hydraulic line.
Connect the slave cylinder to the clutch assembly, attaching its own pushrod into the clutch opening and tightening its mounting bolts. Connect the hydraulic line to the Jeep body with its clips.
Lower the vehicle off the jack stands.
Fill the slave cylinder -- and master cylinder if needed -- with fresh brake fluid.
Open the bleeder screw on the slave cylinder and have another person push on the clutch pedal to bleed air out of the cylinder; hold a small container to the bleeder valve to catch the fluid. Repeat this for the master cylinder.
