Removing and Installing Pistons and Cylinders

Removing and installing pistons (includes removing and installing cylinders)







Tools

Removing pistons and cylinders




Components




Designations and Notes

Removing pistons

Note!
Mark the cylinder bank accordingly before removing the cylinder.

1. Carefully lift the cylinder with the 3 bushings up and off the pistons.

Note!
Mark the pistons using a pen, e.g. 1, 2 or 3.

2. Lever off piston pin circlips with a suitable screwdriver and dispose of.

Note!
The bushings should be marked accordingly





3. Knock bushing out of the cylinder. To do this, insert the pressure piece of the pushing device 9660 at the foot of the bushing and knock the bushing out with a plastic hammer.

4. Remove O-rings of cylinder and O-rings of the bushings and dispose of. Assign bushings to the corresponding piston.

Installing pistons and cylinders

Note!

^Observe installation sequence

^ The central pistons of cylinders 2 and 5 are mounted onto the connecting rod without bushing.

^ The pistons of the outer cylinder 1 - 3 and 4 - 6 are preassembled in the cylinder.




View of the central piston




View of the outer pistons

1. Mount individual pistons. Align the gaps of the piston rings offset by 120°.

Caution!
Risk of damage!
^ Pay close attention to the oil scraper rings when tightening the restraining strap.





2. Oil piston liberally. Mount commercially available restraining strap. Position special tool 9659/9 on top of the piston (piston junk).





3. Align restraining strap. The restraining strap lock should be aligned between the inlet valve recesses.

Note!
^ The assembly sleeve is used to position the restraining strap.
^ Work quickly when positioning to ensure that the piston rings are not damaged.





4. Insert the piston inverted into the assembly sleeve special tool 9657. Quickly press the piston downwards and press the restraining strap downwards at the same time with the other hand.

5. Turn belt pulley or crankshaft clockwise until the connecting rods of cyl. 2 and 5 are at top dead centre.





6. Mount the piston on the connecting rod. Push in oiled piston pin as far as it will go.


Note!
^ A second person's help is recommended for pushing the circlip into the piston.
^ Cover the opening in the crankcase below the piston so that the snap ring can not fall into the crankcase.
^ After assembly, check that the snap ring is seated correctly via a visual inspection.





7. Push on the assembly sleeve 9500/7 with the already premounted piston pin circlip onto the piston pin eye. Insert plunger into the conical assembly sleeve. When doing so, the smaller diameter of the plunger serves as a guide into the piston pin. Push the snap ring into the piston pin retaining groove in the piston using the plunger. The circlip must audibly engage.




Position of the snap ring

8. Prepare the cylinders, outer bushings and piston for installation.





- Insert new O-rings into the cylinders. Grease O-ring areas liberally.





- Mount new O-rings onto the bushings. Grease O-ring area liberally.





- Mount outer bushings in the cylinders. Align the bushings in the cylinder. The flattened areas must face towards the other bushings in longitudinal direction.





- The recesses on the bushing must align with the bores of the studs.





- Mount the outer bushings with pushing device special tool 9660.




View of the mounting tool





- The outer bushings can also be pushed in with an hydraulic press if necessary.





- Oil piston shank. Mount commercially available piston restraining strap. Push piston into the bushing. Push the piston restraining strap downwards at the same time during this procedure.





- Check the position of the pistons. The large inlet valve recesses on the cylinders must face upwards. If necessary turn the pistons in the bushing. Pull the pistons far enough out so that the piston pins can just be inserted.





9. Mount the piston pins into the associated pistons from the inner side. The piston pin should only be inserted so far that the connecting rod can still be mounted.





10. Check pistons for correct installation position. The large valve recesses must face upwards in the installation position.

11. Mount cylinder base seal above the studs.





12. Place spacer special tool 9651 on the outer stud.





13. Push premounted cylinder onto the studs.

Note!
Check that the piston pin circlips are seated correctly!





14. Mount the piston pin and the piston pin circlip of the outer pistons from the inside (through the central cylinder opening).

15. After fitting the piston pin circlip, push the cylinder up to the spacers 9651. Secure the cylinder with the special tool, holder P 140.





16. Prepare central bushing. Fit new O-ring and grease liberally.





17. Position the bushing on the studs.





18. Fit pushing device 9660 on stud. Lay a plastic washer on the bushing and press the bushing into place on the piston by turning the handwheel.





View of the special tool

19. Slowly turn belt pulley or the crankshaft clockwise until the central piston can no longer be seen in the gap between the cylinder and the crankcase. Then press the bushing into place with the pushing device until the restraining strap detaches from the piston shank.





20. Open the restaining strap lock using two screwdrivers and guide the restraining strap out between the crankcase and the bushing.





21. Subsequently press in the central bushing as far as it will go using the handwheel.

22. Remove holder P 140 from the studs.

23. Remove the spacer 9561 again between the crankcase and cylinder.

24. Subsequently push the cylinder in the direction of the crankcase and move to its installation position.

25. To avoid the cylinder bank being pushed out when the horizontal cylinder bank is filled or when the crankshaft is turned, secure cylinder bank with holder P 140.