Removal, defect detection and installation of the flywheel (Opel Astra J)

The flywheel is removed to replace the rear crankshaft oil seal, to replace its toothed rim if it is damaged, and to grind the surface for the clutch driven disk.

You will need: the tools necessary to remove the gearbox and clutch, as well as a 19 mm socket head and a large screwdriver.



1. Remove the gearbox (see Removal and installation the gearbox)…



2. …and clutch (see Removal and installation the clutch).

3. Mark the relative positions of the flywheel and crankshaft in any way.

Note: The flywheel can only be installed on the crankshaft in a certain position because one of the holes in the flywheel and crankshaft is located asymmetrically (with angular offset), however, to facilitate installation of the flywheel, we recommend marking the relative positions of the parts.

4. Remove the six flywheel mounting bolts, holding the flywheel from turning with a screwdriver or tire iron…

Note: For clarity, the photographs of the flywheel removal were taken on a removed engine.

5. …and remove the flywheel.



6. Check the condition of the flywheel rim teeth and, if damaged, replace the flywheel.





7. Replace the flywheel if there are scratches or scoring marks on the mating surface of the clutch driven disk or crankshaft flange.

8. The flywheel can be checked and ground in a workshop with special equipment. The flywheel runout, measured along the toothed rim, should not exceed 0.15 mm. To remove deep scratches and burrs, the mating surface of the driven disk can be ground; the layer of metal removed should not exceed 0.3 mm.

9. Install the flywheel and all removed components in the reverse order of removal. Lubricate the threads of the flywheel mounting bolts with anaerobic thread locker, having first degreased the bolts and the threaded holes for them. Tighten the bolts evenly crosswise to a torque of 35 N·m (3.5 kgf·m), turn them by an angle of 30°, and then by another 15°.