158904-0400 ZEXEL 9 443 612 230 BOSCH TOOTHED GEAR 9443612230 1589040400

Vertical Tachometer Drive
Removal
Fig. 1-Vertical Tachometer DriveRemove cap (1, Fig. 1). Lift gasket (2) out of adapter (3).Turn adapter counterclockwise to remove it. Remove aluminum washer (4). Lift pinion (5) out of flywheel housing (6).Repair
Inspect parts for damage. Replace damaged parts.Installation
Coat pinion with engine oil. Put pinion in flywheel housing so that end of pinion rests on machined pad (7) in flywheel housing. Make sure gear teeth on pinion engage teeth on drive gear. IMPORTANT: Adapter can be installed easily only if gears are in mesh.Put aluminum washer over bottom of adapter. Install adapter in flywheel housing. Tighten adapter securely.Flywheel
Removal
If engine is equipped with a clutch, remove the clutch (Group 4052).
Fig. 2-Flywheel Cap ScrewRemove two cap screws (1, Fig. 2) that hold flywheel on crankshaft. Install two pilot studs through flywheel into crankshaft. Tighten pilot studs securely.
Flywheel weighs 50 to 85 lb. (23 to 39 kg). Plan proper handling procedures to avoid injury.
Remove remaining cap screws (2) that hold flywheel on crankshaft.Install two of the cap screws removed in threaded holes in flywheel. Tighten cap screws evenly to push flywheel off crankshaft.Repair
If engine is equipped with a clutch, inspect clutch contact face on flywheel for scoring, overheating, and cracking.
Fig. 3-Flywheel ThicknessClutch contact face can be resurfaced if there is heat checking. Minimum thickness of flywheel at clutch contact face is: IMPORTANT: If heat checks or cracks can be seen after resurfacing flywheel to minimum thickness, install a new flywheel.Inspect ring gear for worn or broken teeth. If damaged, install a new one (Group 0433).Installation
Install two guide studs in crankshaft rear flange. Tighten guide studs securely.
Flywheel weighs 50 to 85 lb. (23 to 39 kg). Plan proper handling procedure to avoid injury.
Move flywheel into position on guide studs. Push flywheel against crankshaft. IMPORTANT: Install new cap screws each time flywheel is removed.
Fig. 4-Flywheel Cap ScrewInstall cap screws and washers. Tighten cap screws evenly to secure flywheel to crankshaft.Remove guide studs from crankshaft. Install remaining cap screws. Tighten cap screws to 120 lb-ft (163 N m).Install clutch, if used (Group 4052).Flywheel Ring Gear
Removal
Remove flywheel (Group 0433).
Fig. 5-Remove Ring GearSelect a hardwood block (1, Fig. 5) that is slightly smaller than the inside diameter of the ring gear (2). Lay the flywheel, crankshaft side down, on the hardwood block.Using a drift and hammer (3), drive the ring gear off the flywheel. Move drift and hammer around ring gear often to prevent cocking the gear on the flywheel.Installation
Oil fumes or oil can ignite above 380°F (193°C). Use a thermometer and do not exceed 360°F (182°C). Do not allow a flame or heating element to be in direct contact with the oil. Heat the oil in a well-ventilated area. Plan a safe handling procedure to avoid burns.
Fig. 6-ChamferHeat new ring gear evenly in oil (to 360°F [182°C] maximum) or in oven (to 450°F [232°C] maximum) and install hot, with ring gear tooth chamfer (Fig. 6) toward engine side of flywheel. Drive ring gear onto flywheel evenly until it bottoms all the way around on