Part 1
WM 131020 Removing and installing pistons - Turbo
Tools
Technical values
Tools
Tool overview:
Special tools for engine disassembly
Removal
Removing pistons - cylinder bank 1-3
Information
- The specified positions relate to removing and installing components on the engine assembly support with the engine in a vertical position.
- Mark pistons in installation position using a water-resistant marker (e.g. Edding 750).
1. Unscrew screw plug (M30 x 1.5) -1- for removing piston pins.
1.1. Replace sealing ring.
Screw plug for removing/fitting piston pins
To remove a piston-pin circlip:
2. Turn the crankshaft and vibration damper to the bottom dead centre position U 1/4 and lock at this position using a locating pin 9595/1 -1-.
2.1.
U 1/4 marking on vibration damper
WARNING
Preloaded or pressurised components
- Risk of eye injuries
- Risk of bruising
-> Wear personal protective gear.
-> Secure components to prevent them from falling off suddenly.
Information
- Special tool disassembly tool 9764 for removing piston-pin circlips must only be turned in a clockwise direction.
- Always hold the tool firmly with one hand when using it.
- Replace removed piston-pin circlips.
3. Slide special tool disassembly tool 9764 through the assembly bore. The groove for the hook on the circlip -arrow- must be at 9 o'clock position when the engine is positioned vertically.
Groove position for circlip hook (9 o'clock)
4. Disassembly tool 9764 must now be pushed into the circlip.
Positioning groove of special tool 9764 in hook on circlip
4.1. Carefully turn the tool to the left and right. You should feel resistance from the hook.
5. Tighten circlip with tool 9764. To do this, turn the hexagonal handle clockwise until you feel a certain amount of resistance.
Tightening circlip with tool
6. Keep the hexagonal handle -1- tight and turn the pipe -2- clockwise until you feel a certain amount of resistance. At the same time, the cheese head bolt will move horizontally to the left from position A in the guide groove.
Tool 9764 at position A
6.1. Hold the tool firmly at the pipe -2- and press it slightly against the piston. Slowly turn the hexagonal handle -1- using spring force until the cheese head bolt is at position B.
Tool 9764 at position B
6.2. Hold the hexagonal handle -1- firmly and turn the pipe -2- clockwise until you feel a certain amount of resistance. At the same time, the cheese head bolt will move horizontally to the left from position B in the guide groove.
Tool 9764 at stop ahead of position C
6.3. Hold the tool firmly at the pipe -2- and press it slightly against the piston. Slowly turn the hexagonal handle -1- using spring force until the cheese head bolt is at position C. The circlip engages in the tool with an audible click.
Tool 9764 at position C
6.4. Slowly pull the tool and circlip -1- out of the crankcase. Dispose of old circlip.
Pulling tool 9764 out of the crankcase
To remove a piston pin:
Disassembly tool 9777 with 56-mm insert -3- must be used.
Tool 9777 for removing/fitting piston pins
Interchangeable inserts for tool 9777
7. Disassembly tool 9777 must be pushed as far as it will go into the piston pin.
7.1. Hold the tool firmly at the hexagon -1- and turn the hexagon -2- anti-clockwise as far as it will go.
Sliding tool 9777 into piston pin
7.2. Pull out piston pin -1-. Inset shows the tensioned piston pin.
Removing piston pin
7.3. To loosen the piston pin, turn the rear hexagonal handle -2- clockwise until the pin can be removed.
Loosening tool 9777 on piston pin
To remove pistons:
8. Assembly aid 9783 must be inserted into the cylinder bore from the oil pan side. Then press out the piston (by tapping lightly on the handle with the ball of your hand).
8.1. Assign the correct piston pin to the piston immediately.
8.2. Fit assembly aid 9795 -1- (rubber sleeve) on the connecting rod to protect the cylinder liner.
Protective sleeves 9795 for connecting rods 1-3
9. Turn the crankshaft to the bottom dead centre position U 2/5 marking at the vibration damper and lock at this position using a locating pin (tool 9595/1) -1-.
U 2/5 marking on vibration damper
9.1. Repeat steps 3 to 8 for removing piston 2.
10. Turn the crankshaft to the bottom dead centre position U 3/6 marking at the vibration damper and lock at this position using a locating pin (tool 9595/1) -1-.
U 3/6 marking on vibration damper
10.1. Repeat steps 3 to 8 for removing piston 3.
11. Check piston for signs of wear.
=> 1310IN Piston wear, weight groups and identification markings.
Removing pistons - cylinder bank 4-6
Information
- The parting surface between the connecting rod and connecting rod cap is broken during the manufacturing process.
- Assign connecting rod cap to the relevant connecting rod immediately after removal.
- Also check the four-digit matching number.
- Replace connecting rod bolts.
- Replace connecting rod bearings.
1. Remove crankcase half.
=> 1001Z1 Disassembling engine - Turbo.
2. Secure the crankshaft to the main bearing in the middle using special tool holding bridge 9779 -1-.
2.1. Screw in and tighten two fastening screws -2- hand-tight.
Holding bridge 9779 for crankshaft
3. Mark pistons in installation position using a water-resistant marker.
Marking pistons 4-6
4. Screw in three fastening screws -2- for the vibration damper at the crankshaft flange.
4.1. Turn the crankshaft using special tool turning device 9773 -1- so that the connecting rod bolts can be reached.
Turning the crankshaft (without vibration damper)
5. Remove pistons and connecting rods -1- on cylinder bank 4-6.
Connecting rods 4-6
5.1. Loosen and unscrew two external serration screws (M10 x 1.25 x 51) -1- on the connecting rod cap -2-.
Connecting rod cap screws
5.2. Replace connecting rod bolts.
6. Remove pistons 4, 5 and 6 with connecting rods.
6.1. Unscrew the grip handle on assembly aid 9783 and screw the bar -2- into a threaded bore on the connecting rod -1-. Press piston and connecting rod down out of the cylinder bore.
Hold the piston!
Pressing out pistons and connecting rods for cylinder bank 4-6
6.2. Repeat this step for pistons 5 and 6.
7. Remove connecting rods 1-3 -1- on the crankshaft.
7.1. Unscrew connecting rod bolts -2- and remove connecting rod cap and connecting rod.
Connecting rod caps on cylinder bank 1-3
7.2. Replace connecting rod bolts.
8. Dispose of con-rod bearing shells.
WARNING
Preloaded or pressurised components
- Risk of eye injuries
- Risk of bruising
-> Wear personal protective gear.
-> Secure components to prevent them from falling off suddenly.
Procedure for replacing pistons or connecting rods:
9. Insert piston and connecting rod -1- in special tool retaining device 9778 with piston receiving element 9778/1 ( -2- ).
Piston/connecting rod in retaining device 9778
9.1. Carefully remove piston-pin circlips with a small screwdriver.
9.2. Press out piston pin and set aside immediately with the relevant piston.
10. Check piston for signs of wear.
=> 1310IN Piston wear, weight groups and identification markings.
Assembly
Pre-fitting pistons and connecting rods
Information
- Ensure even weight distribution when installing new pistons or connecting rods.
- Only one weight group is permitted per engine.
Component overview
Connecting rod bolts
Tools:
Tool 9778
Information
- The parting surface between the connecting rod and connecting rod cap is broken during the manufacturing process.
- Assign connecting rod cap to the relevant connecting rod immediately after removal.
- Also check the four-digit matching number.
- Replace connecting rod bolts.
- Replace connecting rod bearings.
1. Allocate connecting rod bearings based on the marking on the crankshaft.
1.1. Read off the bearing shell colour from the series of letters -2-. The con-rod marking indicates the con-rod journal. This is read from left to right. The bearings are fitted from the belt side to the flywheel side.