Improved Clutch Components/Flywheel Inspection (95-T-37A)

FLYWHEEL INSPECTION PROCEDURE

1. Using a micrometer, measure flywheel thickness in three places around the circumference of the flywheel. All measurements must be made at the same distance in from the edge of the flywheel and at equal distances from each other. Minimum Flywheel Thickness: 28.25 mm (1.11 in.)
   • If flywheel thickness is not within specification, replace the flywheel.
   • If flywheel thickness is within specification, proceed to next step.
2. Inspect the flywheel ring gear for wear or damage to the teeth. See Fig 1 .
   • If the flywheel ring gear is damaged, replace the flywheel.
   • If the flywheel ring gear is not damaged, proceed to next step.
3. Check flywheel clutch-disc-contact surface for corrosion, chatter marks, scoring, cracking or overheating (indicated by blue discoloration).
   NOTE: Random black spots on the friction surface of the flywheel are normal.
   • If any of these conditions exist, resurface flywheel. (Do not resurface flywheel below the minimum thickness specification of 2.25 mm [1.11 in.].)
   • If none of these conditions exist, proceed to next step.
4. Using a dial indicator, measure flywheel runout. Push the crankshaft forward to take up thrust bearing clearance. Measure the runout at a diameter just inside the pressure plate bolt holes for at least two revolutions. See Fig 2 .
   • Maximum Runout: 0.15 mm (0.006 in.)
   • If the flywheel runout is not within specification, resurface flywheel. (Do not resurface flywheel below the minimum thickness specification of 28.25 mm [1.11 in.].)
   • If the flywheel runout is within specification, proceed to next step.
5. Using a straight edge, check the flywheel for warpage. See Fig 3 .
   • Maximum Warpage: 0.15 mm (0.006 in.)
   • If the flywheel warpage is not within specification, resurface flywheel. (Do not resurface flywheel below the minimum thickness specification of 28.25 mm [1.11 in.].)
   • If the flywheel warpage is within specification, proceed to next step.
6. Inspect inside edge of friction surface toward center of flywheel for a chamfer.
   • If flywheel does not have a chamfer, then a chamfer must be machined into flywheel. Refer to the "Flywheel Chamfering" procedure listed in this bulletin.
   • If flywheel does have a chamfer and all other inspection procedures are within specification with no flywheel damage evident, then flywheel does not need to be replaced.

FLYWHEEL CHAMFERING PROCEDURE

A flywheel is a precision machined part. It must be properly machined to provide effective performance. The flywheel may be taken to a machine shop for machining, or may be machined at a Saturn retail facility using an adapter set on a brake lathe.

• If your Saturn retail facility is equipped with an Accu-turn(TM) Brake Lathe, it is necessary to order an Accu-turn(TM) Flywheel Adapter Set. Call Dealer Equipment at (800) GM-TOOLS (800 468-6657) to order an Accu-turn(TM) Flywheel Adapter Set (P/N 54-436057).
• If your Saturn retail facility is equipped with an Ammco(R) Brake Lathe, the accessories needed for creating a chamfer on the flywheel should be included. The Ammco(R) Brake Lathe offers no provision for measuring depth of cut. The depth of cut can be measured using a dial indicator.

If your Saturn retail facility is equipped with a brake lathe other than the two manufacturers mentioned above, contact that manufacturer's representative for the necessary flywheel machining accessories.

1. Remove clutch cover, clutch disc, and flywheel according to procedures in the appropriate year Manual Transaxle Service Manual.
2. Measure and mark the flywheel in the area to be machined. Measure 60mm-64mm (2.4-2.5 in.) starting from the outside edge of the flat portion of the flywheel moving towards the inside edge of the flywheel. The material to be removed is from the inside edge of the flywheel to the measured mark. See Fig 5 .
3. Perform procedures as follows:
   • For Ammco(R) Lathes: Rotate the lathe spindle hand wheel clockwise (right) to the end of its travel. Then rotate the spindle hand wheel counter clockwise (left) approximately 2 1/2 turns. Mount the flywheel onto the arbor with the clutch side towards the lathe. Slide the centering cone (#3903) with the taper towards the flywheel onto the arbor. Next, slide the centering cone spring (#3110) and hub-less adapter (#9489) onto the arbor. Use double taper adapters (#9193 and #9194), as well as the self-aligning spacer (#9492) to space out the arbor. See Fig 6 .
   • For Accu-turn(TM) Lathes: Using contents found in the flywheel adapter set, mount the first bell clamp, alignment spring, washer, alignment cone, flywheel and second bell clamp onto the lathe arbor. See Fig 7 .
     NOTE: The flywheel is centered on the alignment cone chamfer.