VW Passat & Audi A4 1990-2000

Slave Cylinder



The clutch master and slave cylinders should be replaced as a pair. If one unit fails, the other usually will fail soon after.

NEVER depress the clutch pedal while the slave cylinder is dismounted.

  1. Remove enough brake fluid from the reservoir until the level drops below the refill line connection.
  3. Raise and safely support the vehicle.
  5. Place a suitable drain pan under the slave cylinder.
  7. Using a flare nut wrench loosen, but do not remove, the fluid line.
  9. Remove the retaining bolts and pull the slave cylinder down.
  11. Remove the line from the slave cylinder.

To install:

  1. Install the slave cylinder on the transmission.
  3. Tighten the slave cylinder bolts to 17 ft. lbs. (24 Nm).
  5. Tighten the fluid connections to 12 ft. lbs. (16 Nm).
  7. Make sure to install the cylinder with the bleed screw facing down. When installing the front pushrod, coat it with the proper high temperature grease.
  9. Bleed the system.


The clutch and brake hydraulics use an approved DOT 4 brake fluid in their systems. The hydraulic system should be bled periodically, usually a minimum of every two years, or more often under severe use. Brake fluid can absorb moisture. Because condensation is heavier than brake fluid, and under normal conditions, will not mix with it, the sediment and condensation tend to collect in the slave cylinder and in the bottom of the master cylinder reservoir.

If possible, before bleeding the system, use a siphon gun or a cooking baster to remove the old fluid, or remove the reservoir and flush it using a recommended brake cleaner or rubbing alcohol. If necessary, the reservoir can be flushed while removed from the vehicle using lightly pressurized water, however the reservoir must be flushed with brake cleaner or rubbing alcohol and dried completely before installation.

There are a number of brake hydraulic bleeders available that use vacuum to "pull" the fluid through the hydraulic system. The advantage these tools offer is that the system can be bled without the help of an assistant.

Bleeding or flushing the clutch hydraulic system with dirty or contaminated fluid may result in component damage.

When bleeding a clutch hydraulic system, always observe to following guidelines:

NEVER reuse brake fluid
Always bleed the system using fresh fluid
Do NOT use fluid which has been left uncapped
Use a recommended fluid which is compatible with the existing fluid

  1. Fill the reservoir with fresh fluid.
  3. Fit a flare or box end wrench onto the slave cylinder bleeder screw.
  5. Attach a (clear if available) rubber tube to the slave cylinder bleed screw and suspend it into a suitable clear drain container partially filled with brake fluid.
  7. Open the bleeder screw and have an assistant press the clutch pedal to the floor.
  9. While holding the clutch pedal to the floor, close the bleed screw.
  11. Slowly release the clutch pedal to its fullest extension and recheck the reservoir fluid level. Top off as necessary.
  13. Repeat the above steps until the fluid exiting the bleed screw is clean and free of all air bubbles.
  15. Top off the clutch master cylinder reservoir as necessary.

Click image to see an enlarged view

Fig. A vacuum tester and a bleeding attachment (shown bleeding the brakes here) eliminate the need for a helper. These units are available from automotive vendors