Crankshaft Gear/Sprocket: Service and Repair

Removal





1 Remove radiator and fan.
2 Remove pulley, vibration damper and balancing disc. Service and Repair
3 Completely remove oil pan. Service and Repair
On model 126.120, remove engine. [1][2]Procedures






4 Remove front crankshaft radial sealing ring. Service and Repair






47 Torsion spring
48 Clamp






43 Flange member
56 Fastening bolt

5 Unscrew fastening screw (56) of oil pump sprocket (Fig. step 9).
6 Remove torsion spring (47) from clamp (48) toward the rear.
7 Turn clamp in upward direction.
8 Remove sprocket by means of two screw-drivers.
9 Remove sprocket.
10 Remove double roller chain of oil pump.






Model 116.120






Model 123

11 Disconnect regulating linkage to remove cylinder head cover. Pull out locking eye of longitudinal regulating shaft (arrow).

On models 116.120 and 123, pull longitudinal regulating shaft out of rubber mount in forward direction and remove in rearward direction.






Model 126.120

On model 126.120, pull longitudinal regulating shaft out of guide lever in rearward direction and remove in forward direction.

On models 123 with automatic transmission 722.303 (W4A 040) and 126.120, pull out central plug for vacuum lines (71) or vacuum lines. Disconnect bowden wire, compress black plastic clip (arrow) and pull bowden wire out of holder in rearward direction.






12 Set engine to TDC of 1st cylinder. For this purpose, screw bolt M 18 x 1.5 x 45 with cup washers into crankshaft.

Rotate engine with tool combination at crankshaft.

Attention! Rotate crankshaft only in direction of rotation of engine.






13 Mark camshaft and crankshaft sprocket with paint in relation to timing chain.
14 Remove chain tensioner. Service and Repair






15 Remove camshaft sprocket.

To loosen necked-down screw, apply counterhold to camshaft sprocket by means of a screwdriver or steel bolt, loosen holder for fuel lines and swivel sideways.

16 Remove timing chain from teeth of crankshaft sprocket.






17 Unscrew bolt M 18 x 1.5 x 45.
18 Pull off spacing ring by means of puller.






19 Pull off crankshaft sprocket by means of puller.


Installation
20 Transfer color mark from old crankshaft sprocket to new sprocket.
21 Heat crankshaft sprocket on a hot plate (approx.80 °C) and slip on crankshaft.
22 Knock spacing ring on crankshaft.
23 Insert timing chain and place camshaft sprocket on camshaft. Pay attention to color code.






24 Position necked-down screw for attaching camshaft sprocket and tighten to 80 Nm. For this purpose, apply counterhold to camshaft sprocket by means of a screwdriver or steel bolt.
25 Place double roller chain of oil pump on crankshaft sprocket.
26 Place oil pump sprocket into double roller chain and then slip on drive shaft. Screw-in fastening screw.
27 Set clamp on double roller chain and torsion spring on clamp.
28 Completely install oil pan. For centering of oil pan, slip sleeve on crankshaft journal.
29 Coat front cylinder crankcase housing cover on flange surfaces with sealing compound and position against cylinder crankcase. Screw-in oil pan bolts first.






30 Install front crankshaft radial sealing ring.
31 Install pulley, vibration damper and balancing disc.
32 Rotate engine with tool combination and check adjusting marks.
33 Install chain tensioner.
34 For further installation proceed vice versa to removal.