Part 2
WM 131019 Removing and installing pistons (Continued)12. Unscrew plug for piston pin assembly bore. Use a 12 mm hexagon socket wrench insert.
View: Special tool 9602/3
13. Fasten centering aid, special tool 9602/3, with two countersunk screws with crosshead (M6 x 20) on the crankcase.
Information
^ Centering aid, special tool 960212, is used as from engine numbers 66XO7679 and 68X03514.
View: Special tool 9602/2
14. Align connecting rod of cylinder 6. Insert centering mandrel, special tool 9608, in the assembly bore.
Information
^ The centering mandrel remains in the eye of the connecting rod until the piston contacts the centering mandrel during fitting.
15. Install piston of cylinder 6.
1 Check whether the piston pin circlip is present and was fitted correctly (flywheel side).
2 Before installation, check whether the assembly tube (2) can be moved easily in the piston eye; remove burr if necessary.
16. Move piston to installation position, position the piston ring restraining strap and insert the piston.
Information
^ Generously coat the piston, cylinder and restraining strap with engine oil before fitting the piston.
17. Use the handle of a hammer to tap the piston gently into the cylinder while firmly pressing on the edge of the restraining strap. Use protective gloves.
Information
^ The piston must be fitted in the cylinder carefully and with feeling. If the resistance increases, immediately interrupt the assembly process. Reposition the piston ring restraining strap and repeat the assembly operation.
18. center the piston in the cylinder bore and carefully push it down with the assembly aid (special tool 9698) to the centering mandrel stop.
19. Carefully withdraw the centering mandrel and push the piston down to the stop.
20. Align piston and connecting rod again using the centering mandrel.
21. Push in piston pin as far as it will go into the piston using the pressure pin of special tool 9602.
22. Prepare piston pin circlip for fitting on the piston. It is important to pre-fit the circlip on a firm surface. The circlip must be pre-fitted only immediately prior to fitting on the piston pin eye.
1 Manually insert the new circlip into the conical part of the assembly sleeve, special tool 9603/1.
2 Place assembly sleeve 9603/1 onto the assembly tube of special tool 9602. Use assembly aid, special tool 9500/3, to slide the circlip from the conical sleeve into the assembly tube.
3 Remove assembly sleeve 9603/1 and visually inspect the correct position of the circlip in the assembly tube.
Caution
Danger of injury if circlip springs out!
-> Check position of the circlip only by visual inspection of the assembly tube from the side.
23. Push assembly tube through the centering piece into the crankcase assembly bore with the circlip fitted.
24. Carefully and gently insert the pressure pin until it contacts the piston pin circlip.
25. Move the piston pin circlip to its installation position by briefly and forcefully striking the palm of your hand against the star knob of the pressure pin.
Drawing shows a torch with adjustable mirror
26. Visually inspect correct seating of the piston pin circlip, e.g. with a shop-made electric torch with mirror.
27. Fitting piston in cylinder 5. Advance the crankshaft clockwise until bore U5 on the belt pulley is aligned with the fixing bore on the crankcase. Position or fix with fixing pin.
28. Perform the following assembly steps for piston installation in cylinder 5 as described from Step 14 to Step 26. A spacer sleeve (3) is additionally required when fitting the piston pin circlip in the piston of cylinder 5.
29. Fitting piston in cylinder 4. Advance the crankshaft clockwise until bore U4 on the belt pulley is aligned with the fixing bore on the crankcase. Position or fix with fixing pin.
30. Perform the following assembly steps for piston installation in cylinder 4 as described from Step 14 to Step 26.
31. Two spacer sleeves (3 + 4) are additionally required when fitting the piston pin circlip in the piston of cylinder 4.
32. Remove centering aid 9602/3.
33. Visually inspect correct seating of the piston pin circlip on the piston of cylinder 4.
Information
^ If the piston, piston pin or piston pin circlip are incorrectly assembled, the corresponding piston can be pulled out of the cylinder as follows. Degrease center of piston crown. Coat suitable plastic mandrel with instant adhesive. Allow the adhesive to cure. Pull out piston. Remove plastic mandrel immediately.
34. After fitting the pistons, fit a screw plug and new sealing ring in the assembly bore. Use a 12 mm hexagon socket wrench insert. Tightening torque 80 Nm (59 ftlb.).
View from the belt pulley side
View from the flywheel side
35. Fit guide rail and tensioning rail of cylinder bank 1 - 3 (flywheel side); fit guide rails in correct position.
View from the belt pulley side
36. Fit guide rails and tensioning rails of cylinder bank 4 - 6 (flywheel side); fit guide rails in correct position.
View from the belt pulley side
37. Fit oil pump with coolant guide housing Assembly.
38. Fit intermediate-shaft flange. Grease sealing ring in area of intermediate-shaft flange. Grease take-up bore in area of the crankcase. Carefully press in the intermediate flange.
Screw in new micro-encapsulated hexagon-head bolts M6 x 20 (3 ea.).
Tightening torque 10 Nm (7.5 ftlb.).
Tighten lock nut with the socket wrench, special tool 9110. For this purpose, hold with a slotted screwdriver 7.9 x 1.1 at the slotted threaded pin.
Tightening torque 11 Nm (8 ftlb.).
39. Fit belt pulley.
Information
^ Check whether there are foreign objects in the drive belt grooves of the belt pulley and remove them if necessary.
Tighten hexagon-head bolt using the socket wrench insert 9594; simultaneously hold with retaining device 9593.
Tightening torque 50 Nm (37 ftlb.)
