Balance Shaft & Gear Assembly Inspection
WARNING: This page is about a different car, the 2002 Pontiac Sunfire and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
- Clean all of the balance shaft and gear assembly parts in cleaning solvent. Remove the varnish, sludge and dirt.
- Inspect the balance shaft for the following conditions:
- Scores on the journals
- Burrs on the journals
- Cracks
- Missing pieces
- Inspect the gears for the following conditions:
- Missing teeth
- Chipped teethNOTE: Do not attempt to resurface the balance shaft journals. They have a slight taper and resurfacing the journal may remove the taper. The taper is angled towards the counter weights.
- Replace both shaft even if only one needs to be replaced. Replace the bearings any time the shafts are replaced.
- Measure the journals for the following conditions:
- The correct outside diameter
- An out of round condition
- Measure the gears for backlash using the following procedure:
- 6.1. Place the gear and the shaft assemblies in the housing. The bearings must be installed. Ensure that the timing marks are aligned.
- 6.2. Set up the dial indicator to read off of one tooth of the balance shaft gear.
- 6.3. Hold the other shaft.
Important: If the shafts are not pulled in the same direction, the gears will climb away from each other causing the reading to be incorrect. Do not rotate the gear as you will get incorrect readings.
- While pulling both shafts in the same direction, gently rock the gear in the direction of the rotation to ensure the proper measurements.
- Note the total movement and compare the movement to specifications.
- Replace both the gear and the shaft assemblies if the backlash is out of specification.