Mercedes W124

since 1985-1995 of release

Repair and car operation



W124 Mercedes
+ Governing bodies and control devices
+ MAINTENANCE
+ 2. Maintenance (diesel engines)
+ ENGINE
+ 4. Repair of 6-cylinder petrol SOHC engines
+ 5. Repair of 6-cylinder petrol DOHC engines
+ 6. Repair of the diesel engine established in the car
- 7. Major maintenance of engines
   7.2. General information
   7.3. Recommendations about engine removal
   7.4. Removal and installation of 4-cylinder petrol engines
   7.5. Removal and installation of 6-cylinder petrol engines
   7.6. Removal and installation of diesel engines
   7.7. Sequence of dismantling of the engine
   + 7.8. Analysis of a head of the block of cylinders
   + 7.9. Assembly of a head of the block of cylinders
   7.10. Removal of pistons with rods
   7.11. Removal of a cranked shaft
   7.12. Block of cylinders of the engine
   7.13. Pistons and rods
   7.14. Cranked shaft
   7.15. Survey of radical and shatunny bearings
   7.16. Engine balance of assembly at major maintenance
   7.17. Installation of piston rings
   7.18. Installation of a cranked shaft
   7.19. Check of a working gap of radical bearings
   7.20. Installation of a cranked shaft
   + 7.21. Installation of pistons with rods
   7.22. Engine start after major maintenance
+ COOLING SYSTEM
+ FUEL SYSTEM
+ 10. System of injection of BOSCH CIS-E fuel (KE-JETRONIC)
+ 11. System of injection of BOSCH HFM fuel
+ 12. Fuel system of diesel engines
+ 13. Fuel system of diesel engines
+ SYSTEMS OF START, IGNITION
+ 15. System of ignition of 4-cylinder petrol engines
+ 16. System of ignition of four-cylinder petrol engines
+ PRESTARTING HEATING
+ TRANSMISSION
+ 19. Mechanical transmission
+ 20. Automatic transmission
+ POWER SHAFTS
+ BRAKE SYSTEM
+ SUSPENSION BRACKET
+ BODY
+ ELECTRIC EQUIPMENT
+ CHECK OF MALFUNCTIONS






7.13. Pistons and rods

GENERAL INFORMATION

Removal of piston rings

Removal of a lock ring of a piston finger

Extraction of a piston finger

Opening for oil in a rod head
On 4-cylinder petrol engines and 6-cylinder SOHC engines the small opening for oil in a head of a rod should settle down from a driving chain.

Grooves for loose leaves and a ledge under the piston bottom
On 6-cylinder petrol DOHC engines grooves for loose leaves (1) should settle down from an inlet collector, and the ledge (2) under the bottom of the piston should be from a flywheel.

PERFORMANCE ORDER
1. Before check of pistons with rods remove from pistons piston rings and carefully clear pistons.
2. For removal of piston rings from pistons unclench a ring and insert under a ring evenly on a circle two or three old edges щупа and on them shift a ring from the piston. Be careful, do not scratch the piston the ring ends. Rings very fragile also can burst, if them to unclench very strongly. Working edges of piston rings very sharp, therefore address with them very carefully not to be cut. Hold each set of rings together with pistons for repeated installation them on the places.
3. Clear all traces of a deposit from the top part of the piston.
4. Remove a deposit from flutes under piston rings in the piston, using an old piston ring.
5. After removal of a raid clear the piston with a rod the corresponding solvent and wipe dry.
6. Carefully examine each piston on existence of cracks round a skirt and openings under a piston finger.
7. Check wear on a piston skirt, an opening in a piston head, and also burned in the top part of the piston.
8. Traces of dot corrosion on the piston specify that cooling liquid got to the chamber of combustion. It is necessary to find the reason of hit of liquid in the chamber of combustion and to eliminate it.
9. Measure diameter of the piston.
10. Define a piston gap in the cylinder for what from diameter of the cylinder take away diameter of the piston and divide into two.
11. Check each rod on wear and existence of cracks, and also form distortion.
12. Piston fingers are established on sliding landing and fixed in the piston by two lock rings. On these engines pistons and rods can be divided as follows.
13. Using an edge of a thin screw-driver, remove from the piston a lock ring and a hand squeeze out a piston finger. At repeated installation of a piston finger use only new lock rings.
14. Check a piston finger and the bearing of the top head of a rod on wear.
15. Rods usually do not demand replacement if before it there was no engine jamming.
16. Collect pistons with rods as follows (see fig. An opening for oil in a rod head, Grooves for loose leaves and a ledge under the piston bottom).
17. On 4-cylinder petrol engines and 6-cylinder petrol SOHC engines a small opening for oil in the top part of a rod and an arrow on the bottom of the piston should be directed to a driving chain.
18. On 6-cylinder petrol DOHC engines grooves for the loose leaf of the shatunny bearing in a rod and a cover should be from an inlet collector, and the arrow should be directed on the bottom of the piston to a driving chain. The ledge under the bottom of the piston should be directed to a flywheel.
19. On diesel engines grooves for loose leaves of bearings should be in a rod and a cover of a rod from the fuel pump of a high pressure, and the arrow should be directed on the bottom of the piston to a driving chain.
20. Grease a piston finger and insert it into the piston and the top head of a rod. Check, that the piston easy and freely turned on a piston finger then fix a piston finger new lock rings.