Inspecting the Clutch Hydraulic System

The first step is to locate the source of the leak. Start with the clutch master cylinder, which is mounted next to the brake master cylinder on the firewall. It's smaller, but operates in a similar way. Check around the firewall and also inside the driver’s footwell—worn internal seals may leak into one or both areas.

The second place to check is the slave cylinder, located under the car on the passenger side of the transmission. Inspect the small rubber boot for moisture—if it’s wet with fluid, the slave cylinder needs to be replaced.

When one cylinder fails, the other often isn’t far behind. It's strongly recommended to replace both the master and slave cylinders as a pair to avoid future issues.

One more component to be aware of: Nissan installed a clutch fluid dampener between the master and slave cylinders. This was designed to soften clutch engagement feel.

Many Z31 owners choose to remove the dampener for improved clutch pedal feel. A popular mod is to replace the dampener with a rear outer brake line from a 1982 280ZX (S130). This not only eliminates the dampener but also simplifies the bleeding process by reducing components.

1982 280ZX Rear Outer Brake Line – Replaces Clutch Dampener

Bleeding Process

Items Needed

• DOT 3 Brake Fluid
• 10mm Box or Line Wrench
• DORMAN H380147 Rear Outer Brake Line (280ZX)
• A Friend

Process

1. Top off the clutch master cylinder with DOT 3 brake fluid.
2. Connect a clear hose to the bleeder nipple on the clutch dampener (if equipped), and submerge the other end in a container filled with brake fluid.
3. Have your friend pump the clutch pedal several times and then hold it down.
4. With the clutch pedal held, crack open the bleeder valve to release pressure and fluid.
5. Close the bleeder valve.
6. Repeat steps 3–5 until no more air bubbles are seen in the fluid exiting the hose.
7. Once the dampener is bled, repeat the entire process at the slave cylinder bleeder valve.