Sunroof – Plastic Gear Replacement

Overview

This guide walks you through replacing the plastic gears in the sunroof mechanism of your Porsche 944 with a 16v engine. These gears can strip over time, preventing the sunroof from operating smoothly. Replacing them restores proper function, ensuring you can open, close, or remove the sunroof as needed. This procedure is specific to the later-style mechanism (Feb. 1986 – 1991) found in the 944.

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Tools Required

• Phillips head screwdriver
• Flathead screwdriver (for prying plastic covers)
• 21mm (13/16 inch) wrench
• Ruler or measuring tape
• Bright fingernail polish or marker (for marking lifting arms)
• Grease applicator (e.g., small brush or gloved finger)

Parts Required

• Plastic Sunroof Gear (Feb. 1986 – 1991) – 944-564-430-01 (one per side, recommend ordering two as spares)
• Grease (Porsche TL-VW 745 Universal Cold Grease recommended, or a good-quality heavy grease)

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 section in the rear hatch area (near the hatch compartment light).
2. Gently pull the carpet away by sliding your fingers behind it to release the plastic push plugs.
3. If present, remove the black plastic cover over the motor assembly by unscrewing the four Phillips head screws.
4. Find the large 21mm nut on the drive assembly behind the black plastic cone-shaped dust cover.
5. Rotate the 21mm nut clockwise with a 21mm (13/16 inch) wrench to retract the lifting arms just enough to remove the sunroof. Avoid over-retracting to prevent stripping a good gear if one remains intact.
6. Lift the sunroof out of the car and set it aside.

Step 2: Disassemble the Headliner

7. Lower the back seat and open the rear hatch. Lie on your back in the luggage compartment for easier access.
8. Pull back the weather-stripping along the top edge of the hatch to expose the headliner’s rear edge.
9. Gently pull the headliner loose from the body across the entire edge of the hatch.
10. Locate the cover on the back of the headliner and pry off the plastic screw covers with a flathead screwdriver.
11. Remove the Phillips head screws securing the cover and lift it off to expose the lifting arm mechanisms.

Step 3: Inspect and Remove the Plastic Gears

12. Carefully remove the lifting arm covers one at a time, keeping the gear and lifting arm from falling out.
13. Inspect each plastic gear for stripping. If one gear is still good, replace its cover and use it as a reference later.
14. For any stripped gear, remove the lifting arm and gear, retaining the metal washer on the gear’s back for reuse. (It may stick in the housing due to grease—retrieve it if needed.)

Step 4: Set the Sunroof Motor Position

15. Ensure the sunroof motor cover is off to access the motor and micro-switches.
16. Turn the ignition key to position 2 with the sunroof 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 again.
18. Check the white plastic cam behind the motor assembly through the small opening behind the micro-switches.
19. Verify the cam is hitting the bottom micro-switch (labeled I) but not the top one (labeled II). This is the locked position.
20. If adjustment is needed, turn the 21mm nut counterclockwise with a 21mm (13/16 inch) wrench until the cam clears both switches, then clockwise until it clicks micro-switch I only.

Step 5: Mark the Lifting Arms

21. Examine the sunroof tracks for a sharp “knee” bend where the lifting arm’s round peg sits when locked.
22. Place a lifting arm (without the gear) into its track and slide it until the peg is centered in the knee bend.
23. Mark the lifting arm where it aligns with the edge of the lifting element housing using bright fingernail polish or a marker.
24. Mark the second lifting arm in the same spot by measuring, counting teeth, or comparing side by side.

Step 6: Install the New Gears

25. Remove the sunroof again if reinstalled for Step 4.
26. Place the retained metal washer on the back of the new gear (944 564 430 01).
27. Apply a moderate amount of grease (Porsche TL-VW 745 or a heavy grease) to the gear.
28. Install the gear into the lifting element housing.
29. Insert the lifting arm, aligning the mark with the housing edge, and secure the cover with Phillips screws.
30. Repeat for the other side if replacing both gears.

Step 7: Test and Align the Lifting Arms

31. Turn the ignition key to position 1.
32. Carefully bump the up arrow on the console switch, watching the lifting arms retract toward the housing.
33. Ensure both round pegs hit the housing simultaneously to avoid uneven loading that could strip the gears.
34. Adjust the micro-switches forward or backward if the roof doesn’t lock tightly (peg not hitting the knee correctly).

Step 8: Finalize Installation

35. Reinstall the sunroof into the car.
36. Follow this link to ensure this step – Sunroof Slip Clutch Adjustment – of the process is followed accurately to set the correct torque.
37. Reattach the headliner cover, screws, and weather-stripping in reverse order of removal.
38. Secure the carpet and motor cover (if applicable) back in place.

Post Procedure Checklist

• Check that the sunroof opens, closes, and locks smoothly with the console switch.
• Verify both lifting arms move evenly and pegs align with the track’s knee when locked.
• Ensure no unusual noises (e.g., grinding) occur during operation.
• Confirm the headliner and weather-stripping are secure with no gaps.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manual, Volume 1
• Youtube