Balance Shaft Housing - Removal

Tools Required J 39579  Camshaft Gear Holder

1. Check the balance shaft end play prior to disassembling the balance shaft housing.
2. Set up the indicator to read off the back of the shafts.
3. Press against the shafts and note their movement.
4. Compare the shafts against specifications.
5. If the shafts do not meet specifications, check the thrust plate for wear. Replace the thrust plate if the plate is worn.
6. If the end play does not meet specifications and the thrust plate is not worn, replace the balance shafts.
   Fig 1: Balance Shaft Chain Cover

   Courtesy of GENERAL MOTORS CORP.
7. Remove the balance shaft chain cover.
8. Loosen, but do not remove the balance shaft chain guide.
9. Use the J 39579  to hold the crankshaft.
   NOTE: The balance shaft driven sprocket bolt is left hand threaded and must be loosened by rotating it in a clockwise direction. If the bolt is not loosened in a clockwise direction, it may break.
10. Remove the balance shaft driven sprocket bolt.

    Important:  Mark the surface of the driven sprocket if the sprocket is going to be reused. This will insure that the chain continues to ride on the same tooth surface. Either surface can be placed against the shaft, if a new driven sprocket is installed.

11. Remove the driven sprocket from the shaft.
Fig 2: Balance Shaft Driven Sprocket
Courtesy of GENERAL MOTORS CORP.
12. Remove the balance shaft assembly fasteners and move the assembly to the bench.
13. Clean all of the balance shaft housing parts in cleaning solvent. Remove the varnish, sludge and dirt.
14. Inspect the housings for the following conditions:
    • Cracks.
    • Scored bearing bores.
    • Damaged threaded holes.

    Important:  Replace the entire assembly if the housings are damaged in any way.

15. Clean all of the balance shaft chain cover parts in cleaning solvent. Remove the varnish, sludge and dirt.
16. Inspect the cover for the following conditions:
    • Cracks
    • Broken guides
    • Worn guides