Clutch Replacement

Introduction

Clutch replacement on 924/944/968 models is a substantial undertaking requiring transaxle removal. The following estimated labor times apply:

Vehicle	Time (hours)
944	16
944 Turbo (two-piece crossover pipe)	20
944 Turbo (one-piece crossover pipe)	24

Tools

• Metric socket and wrench set
• Jack stands
• Floor jack
• Clutch alignment tool (944-specific or metric universal)
• 8mm cheesehead tool (12-point internal socket)
• 12mm cheesehead tool (12-point internal — only if the flywheel is to be replaced or removed for resurfacing)
• Slide hammer bearing puller
• Screwdrivers
• 150mm long 8mm thread bolt (for pilot bearing removal — catch-behind-head method)
• Pliers (locking preferred)
• Hammer
• MoS2 grease

Other Procedures Referenced

• EXH-01 Exhaust Manifold Removal and Installation
• TRANS-03 Transaxle Removal and Installation
• IGN-02 Speed and Reference Sensor Replacement
• BOLT-01 Allen Head and Cheesehead Bolt Removal

Removal

1. Place the car on jack stands.

2. Remove the belly pan.

3. Remove the exhaust system from the exhaust headers back, per EXH-01. On 944 Turbo models this includes the crossover pipe; on early cars Turbos with a one-piece crossover, the intake manifold must also be removed.

4. Remove all exhaust system hangers from the torque tube.

5. Disconnect the battery positive lead.

6. Cover the timing mark window on top of the clutch housing with a piece of duct tape. This keeps anything from being inadvertently dropped into the clutch housing.

7. Remove the speed and reference sensors (on top of the clutch housing) per IGN-02.

8. Disconnect the cable clamp next to the speed and reference sensors (the alternator-to-starter cable).

9. Disconnect the two ground wires on top of the clutch housing, near the speed and reference sensors.

10. Remove the heat shield from the starter (if equipped) and disconnect the starter electrical leads.

11. On early vehicles fitted with a support between the engine and clutch housing (near the bottom of the exhaust headers), remove the support.

12. Remove the two starter retaining bolts and remove the starter from the car.

13. Disconnect the cable clamp on the side of the clutch housing, above the starter.

14. On turbocharged cars, loosen the clamp on the wastegate diaphragm hose and remove the hose. Then remove the bolts holding the wastegate bracket to the torque tube and remove the wastegate from the car.

15. Remove the transaxle following the procedure in TRANS-03. This is the most time-consuming portion of the job.

16. Remove the fuel filter.

17. Remove the transaxle carrier.

18. Disconnect the clutch slave cylinder from the clutch housing and hang it out of the way (leave the hydraulic line attached).

19. Support the engine underneath the oil pan with a jack and a block of wood. The block of wood protects the oil pan from damage.

20. Remove the four bolts that attach the torque tube to the clutch housing.

21. Remove the shift lever and shift-lever base plate from the torque tube.

22. Slide the torque tube toward the rear of the car. It is necessary to rotate the torque tube 180° so the triangular tabs on it clear the torsion bar tube.

23. Remove the clutch release-lever retaining bolt from the clutch housing (just above the starter opening in the housing).

24. Thread the 150 mm long 8 mm bolt into the end of the release-lever pivot shaft. Remove the pivot shaft by holding the bolt with pliers and tapping the pliers with a hammer, or by prying with a screwdriver.

25. Remove the four clutch-housing retaining bolts (two at the top of the housing, two at the bottom) and remove the clutch housing and release lever.

26. Inspect the flywheel surface and pressure plate for scoring, heat cracks, or glazing before proceeding.

27. To prevent engine rotation while loosening the pressure plate bolts, use one of the following methods:

• Impact wrench
• Install two pressure plate bolts into the flywheel and hold a screwdriver between them to apply counter-torque
• Hold the crankshaft pulley bolt (24 mm) with a socket and ratchet
• Use a Porsche flywheel lock tool
• Clamp a locking plier on the edge of the flywheel

28. Using the 8mm cheesehead tool, loosen ALL pressure plate bolts before removing any of them. This helps prevent stripping the bolt heads as you reach the last few. Follow the procedure in BOLT-01; keep the tool fully seated in the bolt head at a 90° angle while loosening.

29. Remove the pressure plate, release bearing, and clutch disc together. Note the orientation of the clutch disc (the side marked "Getriebeseite" or "Transmission Side" faces the transaxle).

Note: If a bolt head strips, drill the head off. Replace the pressure-plate retaining bolts with new hardware; if the flywheel is to be resurfaced, replace the flywheel bolts as well.

30. If the flywheel is to be resurfaced, remove the flywheel retaining bolts using the 12mm cheesehead tool.

Note: This is an excellent opportunity to replace the rear main oil seal while the flywheel is removed and access is unobstructed.

31. Remove the pilot bearing from the center of the crankshaft using one of three methods:

• Slide hammer bearing puller — most reliable method; attach to the bearing bore and extract.
• Catch-behind-head bolt method — insert a bolt with a head slightly smaller than the bearing opening, catch the edge of the head behind the bearing, grasp the other end with pliers, and tap on the pliers with a hammer.
• Grease-pack/wooden-dowel method — pack the area behind the bearing completely with grease, insert a close-fitting wooden dowel, and strike the end sharply with a hammer; the hydraulic pressure drives the bearing out. This method has limited success on 944s.

Installation

1. If the pressure plate is being replaced (recommended), transfer the toothed starter ring. The ring fits tightly, so tap around the outside edge with a large-diameter wood dowel or brass punch and hammer to free it from the old pressure plate. Install it on the new pressure plate, ensuring the holes in the starter ring line up with the bolt holes in the pressure plate.

2. Install the new release bearing on the pressure plate (the unusual 944 design — the bearing rides on the pressure plate, not the guide sleeve). If the new bearing does not include a snap ring, reuse the snap ring from the old bearing. Install the spacer(s) onto the release bearing, then insert the bearing into the opening in the pressure plate. While holding the bearing in place, lay the pressure plate friction-side-up on a flat surface and press down on its sides to compress the pressure-plate fingers — this gives enough clearance to fit the snap ring onto the release bearing. The number of spacers used must still allow the snap ring to seat. Once the bearing is in and the snap ring is seated, there should be a small amount of movement between the release bearing and the pressure plate.

3. Install the new pilot bearing into the crankshaft bore. Apply a thin film of MoS2 grease to the inside surface of the bearing (where the end of the driveshaft inserts). Drive it in with a socket matching the bearing's outer diameter, using a socket extension and hammer — contact only the outer race, never the inner race.

4. Install two new needle bearings in the clutch release lever. Apply a small amount of MoS2 grease to the release-lever bearings and to the rubbing surfaces of the release-lever arms (at the release-bearing surfaces and the socket for the slave-cylinder piston).

Note: The Porsche shop manual specifies white solid lubricating paste (AOS 126 0006) for these points. This material hardens over time and can cause sticking. Use MoS2 grease instead.

5. Install the flywheel if it was removed. Torque the flywheel-to-crankshaft bolts to 90 N·m66 ft·lb.

6. Replace the guide sleeve in the clutch housing if needed or desired. If the guide sleeve is replaced, torque the guide-sleeve bolts to 15 N·m11 ft·lb. Coat the inside of the guide sleeve with a light film of MoS2 grease even if it is not replaced.

7. Apply a small amount of MoS2 grease to the splines inside the new clutch disc hub and the splines on the end of the driveshaft (transaxle input shaft).

8. Clean the friction surfaces of the flywheel and pressure plate before installing the clutch — brake cleaner works well. Keep your hands clean when handling the pressure plate and clutch disc.

9. Ensure the pin on the flywheel is pointing straight down.

10. Using the clutch alignment tool, center the clutch disc to the flywheel with the correct face toward the transmission ("Getriebeseite"). Ensure the tool is inserted fully into the pilot bearing.

11. Install the pressure plate with all bolts partially threaded before final torque. Tighten the bolts a few turns at a time, alternating around the circumference so the pressure plate is pulled down evenly onto the flywheel. Torque the pressure plate bolts to 25 N·m18 ft·lb.

12. Remove the clutch alignment tool.

13. Apply a thin coat of MoS2 grease to the inside surface of the guide sleeve in the clutch housing.

14. Locate the release lever in the clutch housing and install the housing (with the release lever) onto the block. The block has alignment pins to locate the housing. Install the clutch-housing bolts and torque to 75 N·m55 ft·lb.

15. Position the release lever so it aligns with the pivot-shaft opening in the clutch housing.

16. Slide the pivot shaft into the clutch housing until it is fully seated.

17. Install the pivot-shaft retaining screw and torque to 9.5 N·m7 ft·lb. Tighten the locking nut against the clutch housing and torque to 7.5 N·m6 ft·lb.

18. Push the central tube forward and bolt it to the clutch housing. Leave these mounting bolts loose until the transaxle is installed.

19. Install the transaxle carrier. Torque the transaxle-carrier-to-body bolts to 46 N·m34 ft·lb.

20. Reinstall the transaxle per TRANS-03. When joining the engine and transaxle, do not allow the weight of the transaxle to hang on the clutch disc — keep it supported on the jack until the input shaft is fully seated.

21. On turbocharged cars, install the wastegate. Do not tighten the bracket bolts until the exhaust system is completely installed.

22. Install the clutch slave cylinder and torque its mounting bolts to 21 N·m15 ft·lb.

23. Install the starter and attach the wiring harness. Torque the starter mounting bolts to 45 N·m33 ft·lb. Install the starter heat shield (if equipped). Attach the starter wiring harness to the clutch housing at the two points with sleeve clamps.

24. On early vehicles with a support between the engine casing and clutch housing, install the support and torque the bolts to 42 N·m31 ft·lb.

25. Attach the ground straps at the top of the clutch housing.

26. Install the exhaust system hangers onto the torque tube.

27. Reinstall the sections of the exhaust system removed for the clutch replacement per EXH-01.

28. Reinstall the speed and reference sensors per IGN-02.

29. Attach the two ground wires to the top of the clutch housing.

30. Install the belly pan and connect the battery.

31. Bleed the clutch hydraulic system and verify full clutch engagement and release before road testing.

Torque Specifications

Fastener	Torque
Flywheel to crankshaft bolts	90 N·m66 ft·lb
Guide sleeve bolts (if replaced)	15 N·m11 ft·lb
Pressure plate bolts	25 N·m18 ft·lb
Clutch housing bolts	75 N·m55 ft·lb
Pivot shaft retaining screw	9.5 N·m7 ft·lb
Pivot shaft locking nut	7.5 N·m6 ft·lb
Transaxle carrier to body	46 N·m34 ft·lb
Clutch slave cylinder mounting bolts	21 N·m15 ft·lb
Starter mounting bolts	45 N·m33 ft·lb
Engine/clutch housing support (early vehicles)	42 N·m31 ft·lb