Balance Shaft Oil Seal Replacement

Overview

This guide walks you through replacing the balance shaft oil seals on a Porsche 944 S2 with its 3.0L engine. These seals keep oil from leaking out of the balance shaft housing, which is critical for maintaining engine lubrication and performance. We’ll also cover resealing the balance shaft cover if needed, though this step is optional unless you spot a leak.

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Tools Required

• Jack stands
• Floor jack
• Metric socket set
• Metric wrench set
• Porsche Timing Belt Tension tool (P9201)
• Flywheel Lock (P9206)
• Balance Shaft Pin Spanner (P9200) or equivalent
• Gear puller
• Seal puller
• Small screwdriver or probe
• Bearing grease
• Loctite 574 and velour roller (if balance shaft cover is removed)

Parts Required

• Balance shaft main seal (upper) – 944 101 911 00
• Balance shaft main seal (lower) – 944 101 912 00
• Balance shaft support o-ring – 999 701 632 40
• Rear housing plug o-ring (if replaced) – 999 701 633 40
• Thin plastic seal (bearing cap-to-cover) – 944 101 913 00 (if balance shaft cover is removed)

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Flywheel Lock Installation
• Locating and Setting Engine to Top Dead Center (TDC), Cylinder 1
• Air Filter Housing and Air Flow Sensor – Removal
• Balance Shaft Belt Removal
• Balance Shaft Belt Installation
• Balance Shaft Belt Tension – Checking and Adjusting
• Balance Shaft Sprocket Installation and Alignment

Step-by-Step Procedure

Step 1: Prepare the Engine

1. Raise the front of your Porsche 944 S2 using a floor jack and secure it on jack stands.
2. Follow this link to ensure this step – Flywheel Lock Installation – of the process is followed accurately.
3. Follow this link to ensure this step – Locating and Setting Engine to Top Dead Center (TDC), Cylinder 1 – of the process is followed accurately.
4. Follow this link to ensure this step – Air Filter Housing and Air Flow Sensor – Removal – of the process is followed accurately to remove the air intake components.

Step 2: Remove the Belts and Components

5. Follow this link to ensure this step – Balance Shaft Belt Removal – of the process is followed accurately to remove the camshaft and balance shaft belts, rollers, tensioners, balance shaft sprockets, crankshaft gears, and rear timing cover.
6. Locate the woodruff key in the balance shaft slot and gently pull it out with your fingers or a small screwdriver.

Step 3: Disassemble the Balance Shaft Support

7. Find the three retaining bolts holding the front balance shaft support in place (these are 13mm bolts on the S2). Use a 13mm wrench to remove them.
8. Slide the front balance shaft support off the end of the balance shaft carefully.

Step 4: Remove and Replace the Seals

9. If you’re resealing the balance shaft cover or replacing the rear plug o-ring, remove the balance shaft cover bolts (10mm) and take off the cover and rear plug.
10. Use a seal puller to remove the main seals from the front of the balance shaft support. If you don’t have a seal puller, slide a small screwdriver under the inside lip of the seal and pry it out gently.
11. Take the spacer out of the balance shaft support.
12. Use a small screwdriver or probe to remove the large o-ring from the balance shaft support.
13. Apply a thin layer of bearing grease to the o-ring groove in the balance shaft support, then install the new o-ring (999 701 632 40). Add a thin coat of grease to the outside of the o-ring.
14. Coat the contact surfaces of the spacer with bearing grease and slide it back into the support housing.
15. Apply bearing grease to the sealing surfaces of the new main balance shaft seals. Note: The upper seal (944 101 911 00) and lower seal (944 101 912 00) differ by 1mm in diameter—double-check you’re using the right one for each position.
16. Slide the correct main seal into the front of the support and tap it into place using a socket slightly smaller than the seal’s outside diameter.

Step 5: Reassemble the Balance Shaft Cover (If Removed)

17. If you removed the balance shaft cover, install a new o-ring (999 701 633 40) onto the rear housing plug and position it into the housing.
18. Apply a thin coat of Loctite 574 to the cover mating surface using a velour roller, then position the cover onto the balance shaft housing.
19. Install the balance shaft cover retaining bolts (10mm) and tighten them finger-tight for now.
20. Install the thin plastic seal (944 101 913 00) onto the end of the balance shaft to ensure proper oil flow to the upper bearing.

Step 6: Reinstall the Front Support

21. Slide the front support (with the spacer and seal installed) onto the balance shaft and push it into the front of the housing until it’s fully seated.
22. Install the three front support retaining bolts (13mm) and tighten them finger-tight.
23. If the balance shaft cover was removed, torque the cover bolts to the S2-specific spec of 20 Nm (15 ft-lbs) in a crisscross pattern.
24. Torque the front support bolts (M8) to 20 Nm (15 ft-lbs) using a torque wrench.

Step 7: Final Reassembly

25. Follow this link to ensure this step – Balance Shaft Belt Installation – of the process is followed accurately.
26. Follow this link to ensure this step – Balance Shaft Belt Tension – Checking and Adjusting – of the process is followed accurately.
27. Follow this link to ensure this step – Balance Shaft Sprocket Installation and Alignment – of the process is followed accurately.

Post Procedure Checklist

• Check for oil leaks around the balance shaft seals and cover after running the engine for 5 minutes.
• Ensure the balance shaft and camshaft belts are properly tensioned by rechecking with the Porsche Timing Belt Tension tool (P9201).
• Verify smooth engine operation with no unusual noises from the balance shafts.

Sources

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