Balance Shaft Cleaning and Inspection

Important:  The balance shaft and the balance shaft front bearing are serviced only as an assembly. Do not remove the balance shaft front bearing from the balance shaft.

1. Clean the following components in cleaning solvent:
   • The balance shaft (1)
   • The balance shaft retainer (2)
   • The balance shaft rear bearing
   • The balance shaft driven gear (4)
   • The balance shaft drive gear
2. Dry the following components with compressed air:
   • The balance shaft (1)
   • The balance shaft retainer (2)
   • The balance shaft rear bearing
   • The balance shaft driven gear (4)
   • The balance shaft drive gear
   Fig 1: Cleaning Balance Shaft

   Courtesy of GENERAL MOTORS CORP.
3. Inspect the balance shaft bearings for the following:
   • Front ball bearing for damage or wear
   • Front ball bearing for smoothness of operation
   • Rear sleeve bearing for wear, scoring, or other damage
4. Inspect the balance shaft (1) for the following:
   • Wear or scoring on the rear bearing journal
   • Damaged bolt hole threads
   • Damage to the balance shaft driven gear locator pin
5. Inspect the balance shaft retainer (2) for wear or damage.
6. Inspect the balance shaft retainer bolts (3) for damaged threads.
7. Inspect the driven gear (4) for the following:
   • Excessive wear or damage
   • Nicks, burrs, or scoring
8. Inspect the driven gear bolt (5) for damaged threads.
9. Inspect the balance shaft drive gear for the following:
   • Excessive wear or damage
   • Nicks, burrs, or scoring
   Fig 2: Inspecting Balance Shaft

   Courtesy of GENERAL MOTORS CORP.