Pic. 77. The main dimensions of the flywheel (see text),
a - see text,
b - see text,
A - contact surface,
B - bearing surface of the clutch cover,
C - bearing surface of the crankshaft.
Drive discs are interchangeable for all engine series. The flywheel or drive discs together with the ring gear can be replaced without balancing the crankshaft. Replacement can be made on the engine installed on the car.
Remove gearbox.
While holding the flywheel or drive discs from turning with a screwdriver or in another way, unscrew the mounting bolts. Holes are drilled between the mounting bolts in the drive disks and in the crankshaft, which must be aligned during assembly. On fig. 78 shows the location of the holes in the drive disks.
Pic. 78. The location of the dowel pin in the drive discs.
Remove flywheel or drive discs. Remove spacer washers for drive discs.
Measure the minimum diameter of the mounting bolts. If the size is less than 8.1 for the flywheel mounting bolts or less than 7.3 mm for the drive disc mounting bolts, the bolts must be replaced. Measure with a vernier caliper as described for the connecting rod cap bolts. For 110 series engines, the mounting bolts are different and differ in the shape of the bolt head, this must be taken into account when replacing the bolts. Changed bolts can be used on older engines.
If the working surface is worn or burnt out, the flywheel can be machined. Mercedes workshops have repair dimensions. To replace the ring gear, a heat source is required that can heat up to 220°C.
Mark the mutual position of the flywheel and the ring gear and fix the flywheel in a vice.
Drill the ring gear between two teeth.
Observing safety measures, break the ring gear with a chisel.
Thoroughly clean the seating surfaces on the flywheel.
Heat up a new ring gear to the above temperature and quickly put it on the flywheel using pliers. Seize the crown with a soft metal mandrel.
To replace the gear rim on the drive disks, unscrew the bolts securing the gear rim and the steel disk to the drive disks. Install new ring gear and tighten bolts.
Pay attention when installing:
Put the flywheel or drive disks on the crankshaft, aligning the mounting holes. When installing drive discs, pre-install spacer rings.
Screw in the mounting bolts and tighten them to a torque of 30...40 Nm, then turn the bolt heads by 90°...100°, i.e. a quarter turn. Turning the head is necessary for the correct operation of the mounting bolts.
Pic. 79. Flywheel and drive discs.
1 - starter drive ring gear,
2 - flywheel,
3 - locating pin,
4 - flywheel mounting bolt,
5 - starter drive ring gear,
6 - flywheel for automatic transmission,
7 - drive disk,
8 - remote washer,
9 - locating pin,
10 - a bolt of fastening of disks of a drive.