Camshaft sprocket
Removing
1. Remove the top drive chain cover.
2. Set the piston of the first cylinder to top dead center and check that all the alignment marks are aligned with the pointers.
3. Remove the drive chain tensioner.
4. Using paint, apply alignment marks to the camshaft sprocket and drive chain link, and the camshaft sprocket and camshaft.
5. Unscrew the three bolts, remove the sprocket from the camshaft and remove it from the drive chain. Keep the drive chain taut at all times to prevent the drive chain from coming off the crankshaft sprocket.
6. Remove the segment key from the camshaft groove.
Examination
1. Check the condition of the teeth on the sprocket. The teeth on the sprocket are symmetrical and if one side of the teeth is worn out, the sprocket must be replaced.
Installation
Attention! The camshaft sprocket has several modifications, therefore, when replacing the sprocket, it is necessary to consult with Mercedes-Benz representatives.
1. Install the keyway into the groove on the camshaft
2. Check that all alignment marks are aligned with the pointers. When installing a new camshaft sprocket, apply alignment marks to it in the same places as on the old sprocket.
3. Put the chain on the sprocket, matching the previously applied marks.
4. Install the sprocket on the camshaft in accordance with the marks previously applied and secure it with bolts.
5. Install the drive chain tensioner.
6. Turn the engine crankshaft 2 full turns clockwise and check that all alignment marks are aligned with the pointers.
7. Install the upper drive chain cover.
Crankshaft sprocket
Removing
Attention! When removing the crankshaft sprocket, one link in the oil pump drive chain must be cut. Therefore, either prepare a new chain link or a new oil pump chain. A puller must be used to remove the crankshaft sprocket.
Attention! When removing the chain, use an emery wheel or vulcanite to cut off the protruding hats of one of the chain links.
Remove shoe from pivot pin (1) oil pump drive chain tensioner, bushing (2) and spring (3)
1. Remove the drive chain tensioner shoe.
2. Close the oil pan with a clean cloth.
3. Remove the oil pump drive chain tensioner shoe from the pivot pin. Remove the bushing and spring from the pivot pin. At the same time, mark the location of the spring for proper re-installation of it in place (see picture).
4. Using an emery stone or vulcanite, grind down the riveted ends of the oil pump drive chain link on top of the crankshaft sprocket.
5. While supporting the chain, remove the retainer plate and drive the connecting link out of the chain.
6. Being careful not to get chips into the oil pan, remove the rag covering the oil pan.
7. Using soft wire, tie off the ends of the oil pump drive chain so that it does not come off the oil pump sprocket.
8. Put alignment marks on the drive chain and camshaft sprocket, then remove the drive chain from the sprocket.
9. Remove the drive chain from the crankshaft sprocket. Mark the orientation of the sprocket and, using a puller, remove the crankshaft sprocket.
10. Remove the keyway from the crankshaft groove.
Examination
1. Check the condition of the teeth on the sprocket. The teeth on the sprocket are symmetrical and if one side of the teeth is worn out, the sprocket must be replaced.
Installation
1. Install the keyway into the groove of the crankshaft.
2. When installing a new sprocket, transfer the marks from the old sprocket to the same places on the new sprocket.
3. Heat the crankshaft sprocket to 50°C, align the groove in the sprocket with the key, and install the sprocket onto the crankshaft.
4. Install the drive chain on the camshaft sprocket according to the previously marked marks.
5. Install the drive chain on the crankshaft sprocket, matching the marks on the sprocket and chain.
6. Position the ends of the oil pump drive chain on the crankshaft sprocket, then connect the ends of the chain with a connecting link. Install the fixing plate on the connecting link and rivet the connecting link. Check that no metal burrs remain after riveting.
7. Install the bushing, spring and tensioner shoe on the pivot pin.
8. Install the drive chain tensioner shoe.