Front crankshaft oil seal
1. Remove the pulley/damper and crankshaft hub according to paragraph 5.
2. Measure and record the cuff seat depth.
3. Pull out the cuff using a suitable hook-shaped tool. You can remove the cuff by drilling a small hole in it and screwing a self-tapping screw into it. Then grab it with pliers and pull out the cuff.
4. Clean the cuff socket.
5. Dip the new seal in clean engine oil and press it into place (open side forward) to a pre-measured depth, using a suitable socket wrench or pipe. In order not to damage the cuff with the shaft during its installation, it will be useful to wind thin plastic or adhesive tape around the end of the crankshaft
6. After installing the cuff, remove the protective plastic from the crankshaft.
(Article was borrowed from the website www.mercedesman.ru)
7. Install the pulley/damper and crankshaft hub in accordance with paragraph 5.
Rear crankshaft oil seal
8. Remove the flywheel/faceplate in accordance with paragraph 13.
9. Perform the operations described in points 2 and 3.
10. If you cannot remove the oil seal by levering it out, you can unbolt the oil seal housing from the cylinder block, remove the housing, and knock it out of the housing. Keep in mind that this requires unbolting the bolts that secure the oil pan to the rear of the oil seal housing—be careful not to damage the oil pan gasket. If necessary, remove the oil pan as described in paragraph 11 and install a new gasket.
11. Check the crankshaft at the point of contact with the cuff for signs of damage. If severe wear is detected, the crankshaft must be replaced.
12. Clean the oil seal housing and the surrounding area on the crankshaft flange.
13. Dip the new seal in clean engine oil and press it into place (open side forward) to the pre-measured depth, using a suitable socket wrench or pipe. It may be useful to wrap thin plastic or adhesive tape around the end of the crankshaft to prevent the shaft from damaging the seal when installing it. Note that in order for the seal to provide a satisfactory seal, it must be installed strictly perpendicular to the shaft, without any distortions.
14. If the cuff housing was removed, apply sealant to the adjacent surface of the cylinder block when installing it. Install the cuff housing and tighten the mounting bolts to the required tightening torque.
15. After installing the cuff, remove the protective plastic from the crankshaft.
16. Install the pulley/damper and crankshaft hub in accordance with paragraph 5.