Replacement: Replacing all pistons

NOTE: TECHNICAL INFORMATION
Wear safety goggles.

NOTE: The description is provided only at one component. The procedure is the same for all other components.

Use the special tools 2 455 002, 2 410 685 and 2 447 297 to remove the piston from the connecting rod.

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CAUTION:
Piston pin snap ring with preload .
Injury hazard!
- The use of the specified special tool for the disassembly or installation is mandatory.
- Wear safety goggles.
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Use the special tool 2 447 297 to remove the piston pin snap ring.
Insert the flat side (3) of the special tool 2 447 297 in the groove (4) .
Use the curved side (2) to grip and remove the piston pin snap ring (1) .

Check

NOTE: TECHNICAL INFORMATION
Piston and piston pin are matched to each other.
Always install piston and piston pin together and do not switch by mistake.

Check whether the piston pin (1) has noticeable play in the piston.
Check whether the piston pin (1) can be removed without excessive force.

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Result

» The piston pin (1) can only be removed with difficulty or the piston pin (1) has noticeable play.

Measure
- Replace the piston (2) and the piston pin (1) .
Parts: Piston, piston pin

To replace the piston, the piston pin length must be determined .

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Engine	Piston pin length	Pistons
B38M1 ECE	12x55 mm	8 678 931
B38M1 ECE	12.5X55 mm	8 678 931
B38M1 ECE	12X51 mm	9 494 399
B48M1 ECE	12x55 mm	8 678 931
B48M1 ECE	12.5X55 mm	8 678 931
B48M1 ECE	12X51 mm	9 494 399
B38M1 CN	12X55 mm	8 678 931
B38M1 CN	12.5X55 mm	8 678 931
B38M1 CN	12X52 mm	8 681 079
B48M1 CN	12X55 mm	8 678 931
B48M1 CN	12.5X55 mm	8 678 931
B48M1 CN	12X52 mm	8 681 079
B48O1 ECE+CN	12X55 mm	8 678 934
B48O1 ECE+CN	12.5X55 mm	8 678 934
B48T1 ECE+CN	12.5X59 mm	9 488 343

NOTE: TECHNICAL INFORMATION
Piston and piston pin are matched to each other.
Always install piston and piston pin together and do not switch by mistake.

Install new piston pins (1) in the new piston (2) and the connecting rod (3) .

Courtesy of BMW OF NORTH AMERICA, INC.
CAUTION:
Piston pin snap ring with preload .
Injury hazard!
- The use of the specified special tool for the disassembly or installation is mandatory.
- Wear safety goggles.
Courtesy of BMW OF NORTH AMERICA, INC.
Position the piston pin snap ring (1) .
The opening (mark) of the piston pin snap ring must point towards the piston crown (2) .
Preload the piston pin snap ring (1) with your thumb.
Press the piston pin snap ring simultaneously with the special tools 2 410 685 and 2 455 002 in the piston.
Add the special tool 2 410 685 in a rotating manner and press the piston pin snap ring completely into the piston.

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Check whether the piston pin snap ring (1) fits correctly in the groove (2) .
Check whether the opening (mark) of the piston pin snap ring points towards the piston crown (3) .

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