Sunroof – Plastic Gear Replacement – 2.5L NA

Overview

This procedure guides you through replacing the plastic gears in the sunroof mechanism of a Porsche 944 8-valve engine configuration variants, 85.5 Onwards, 1986–1988). These gears can strip over time, preventing the sunroof from operating correctly. Replacing them restores smooth operation. This guide is specific to the late-model (85.5 Onwards) sunroof mechanism with a single drive cable guide tube. For Pre-85.5 models (1983–1985.5), the procedure differs due to the old-style mechanism, which uses multiple guide tubes and is not covered here. Consult the Porsche 944 Workshop Manuals or other resources for Pre-85.5 models.

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Tools Required

• Phillips head screwdriver
• 21mm (13/16 inch) wrench
• Small flathead screwdriver (for prying plastic covers)
• Ruler or measuring tape
• Marker (e.g., bright nail polish)

Parts Required

• Plastic sunroof gear (two recommended) – 944-564-430-01
• Heavy-duty grease (Porsche TL-VW 745 Universal Cold Grease or equivalent)

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Sunroof Slip Clutch Adjustment

Step-by-Step Procedure

Step 1: Remove the Sunroof

1. Locate the sunroof motor assembly behind the vertical carpet in the rear hatch area, near the hatch compartment light.
2. Gently pull the carpet to remove the plastic push plugs securing it.
3. If the motor assembly has a black plastic cover, remove it by unscrewing the four Phillips head screws.
4. Locate the 21mm (13/16 inch) nut behind the black plastic cone-shaped dust cover on the drive assembly.

For 85.5 Onwards models:

• If the lifting arms are not retracted, rotate the 21mm (13/16 inch) nut clockwise using a 21mm (13/16 inch) wrench to retract them. Rotate only enough to allow sunroof removal to avoid stripping any remaining good gears.

For Pre-85.5 models:

• This procedure does not apply to the old-style mechanism. Consult the Porsche 944 Workshop Manuals for the correct procedure.

5. Remove the sunroof from the car once the lifting arms are retracted.

Step 2: Disassemble the Headliner

6. Lay on your back in the luggage compartment with the rear seat down and the rear hatch raised for easier access.
7. Pull back the weather-stripping along the top edge of the hatch to expose the headliner’s back edge.
8. Gently pull the headliner loose from the body across the entire edge of the hatch to access the lifting arm mechanisms.
9. Verify that your sunroof has the late-model mechanism (85.5 Onwards), identified by two lifting arm boxes with a single drive cable guide tube along the bottom.

For Pre-85.5 models:

• If you see a box between the mechanisms with multiple guide tubes, you have the old-style mechanism, and this procedure does not apply. Refer to the Porsche 944 Workshop Manuals.

Step 3: Inspect and Remove Faulty Gears

10. Carefully remove one lifting arm cover at a time, ensuring the gear and lifting arm do not fall out.
11. Inspect the plastic gear for damage. If the gear is intact, replace the cover and use it as a reference for setting the other lifting arm.
12. For a damaged gear, remove the lifting arm and plastic gear, retaining the metal washer on the back of the gear for reinstallation. The washer may stick in the mechanism housing due to grease.
13. Repeat for the other lifting arm, replacing only the damaged gear(s).

Step 4: Set the Sunroof Motor Position

14. Remove the sunroof motor cover if not already done.
15. Locate the two micro-switches above the motor and the white plastic cam on the back side of the motor assembly.
16. Turn the ignition switch to position 2 and ensure the sunroof is installed (temporarily place it back if removed).
17. Press the up arrow on the console switch until the motor stops, then press the down arrow until it stops.
18. Check the cam position through the small opening behind the micro-switches. The cam should contact the bottom micro-switch (labeled I) but not the top micro-switch (labeled II).
19. If the cam is incorrectly positioned, adjust it manually using the 21mm (13/16 inch) nut:

• Turn the nut counterclockwise to move the cam away from the micro-switches until it clears both.

• Turn the nut clockwise until the cam contacts micro-switch I, listening for a click.

20. Verify micro-switch II by rotating the nut clockwise until it clicks, then return the cam to contact only micro-switch I.
21. If the micro-switches do not click, remove them and slightly bend the mounting arm to ensure proper contact with the cam.

Step 5: Mark the Lifting Arms

22. Examine the sunroof tracks, noting the sharp bend (knee) where the lifting arm’s round peg sits when the roof is locked.
23. With the sunroof installed and closed, place a lifting arm in its track within the lifting element (the box housing the gear and arm).
24. Slide the lifting element until the round peg aligns with the middle of the knee in the track.
25. Mark the lifting arm where it aligns with the edge of the lifting element using bright nail polish or a marker.
26. Remove the lifting arm and mark the second lifting arm at the same position by measuring, counting teeth, or comparing side by side.

Step 6: Install New Gears

27. Remove the sunroof from the car if not already done.
28. Ensure the metal washer from the old gear is placed on the back of the new 944-564-430-01 gear.
29. Apply a moderate amount of heavy-duty grease (Porsche TL-VW 745 Universal Cold Grease or equivalent) to the new gear.
30. Install the greased gear into the lifting element housing.
31. Insert the lifting arm, aligning the mark made in Step 5 with the edge of the housing.
32. Secure the lifting arm cover with the Phillips head screws.
33. Repeat for the other side if replacing both gears.

Step 7: Check Lifting Arm Alignment

34. Turn the ignition key to position 1.
35. Carefully press the up arrow on the console switch in short bursts to retract the lifting arms toward the lifting element housing.
36. Observe the round pegs on both lifting arms, ensuring they reach the housing (mechanical stop) simultaneously to prevent gear stripping due to uneven loading.

Step 8: Adjust Slip Clutch Torque

37. Before operating the sunroof fully, check and adjust the slip clutch torque to prevent gear stripping.

• Follow this link to ensure this step – Sunroof Slip Clutch Adjustment – is followed accurately.

Step 9: Reinstall and Test the Sunroof

38. Install the sunroof back onto the car.
39. Test the sunroof operation using the console switch, ensuring it opens, closes, and locks smoothly.
40. If the sunroof does not lock tightly (e.g., the pegs do not align with the knee in the track), adjust the micro-switches:

• Move the micro-switches forward to stop the arms closer to the released position.

• Move the micro-switches backward to stop the arms closer to the raised position.

Post Procedure Checklist

• Verify that the sunroof opens, closes, and locks securely without binding.
• Check that both lifting arms move synchronously and reach the mechanical stop simultaneously.
• Ensure no grease or debris is left on the headliner or sunroof tracks.
• Confirm the slip clutch torque is set correctly to prevent future gear stripping.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manuals
• YouTube