Remove/install piston rings

AR03.10-D-7311TSV

Remove/install piston rings

06.03.2020

Engine

642 in model 907

1

Piston ring (compression ring)

2

Piston ring (compression ring)

3

Piston ring (oil scraper ring)

4

Garter spring

8

Hooked spring

10

Pliers

Measure vertical clearance

Measure end gap

 Caution

Risk of injury caused by scraping or cutting body parts on sharp vehicle parts

Always wear protective gloves when working on or near sharp and non-deburred vehicle parts.
Deburr repair panels.

AS00.00-Z-0017-01A

 

Remove/install

1

Remove the piston.

AR03.10-D-7021TSV

2

Determine the vertical clearance of the piston rings (1, 2, 3) using a feeler gauge.

 Commercially available devices/tools
Feeler gage

Piston ring vertical clearance

*BE03.10-N-1003-02Q

If the vertical clearance is excessive,



Replace the piston and piston rings (1, 2, 3).

3

Remove the piston rings (1, 2, 3) from the piston using pliers (10).

 Installation: Note the installation position of piston rings (1, 2, 3). The lettering "Top" or the name of the manufacturer must point towards the piston crown.

 Installation: Insert the hook spring (8) with the garter spring (4) with a 180° offset relative to the ring gap for the piston ring (3).
Install the piston rings (1, 2) with the ring gaps offset by 120°.

 Pliers

*000589513700



Clean

4

Clean the grooves in the piston rings (1, 2, 3) in the piston.

Assembly cleaner

*BR00.45-Z-1028-04A

5

Clean cylinder barrel.

Assembly cleaner

*BR00.45-Z-1028-04A



Check

6

Check the piston rings (1, 2, 3) for damage / chippings on the coating.

Depending on the findings,



Replace the piston ring (1, 2, 3).

7

Check the end gap of the piston rings (1, 2, 3).

 Insert the relevant piston ring (1, 2, 3) in the unused area of the cylinder barrel.

Piston ring end gap

*BE03.10-N-1004-02Q

If the end gap is excessive,



Replace the piston ring (1, 2, 3).

8

Install in the reverse order.

Test specifications for pistons

Number

Designation

Engine 642 in model 906, 907

BE03.10-N-1003-02Q

Piston ring vertical clearance

Groove 1

mm

0,18...0,24

Groove 2

mm

0,05...0,10

Groove 3

mm

0,03...0,07

Test specifications for pistons

Number

Designation

Engine 642 in model 906, 907

BE03.10-N-1004-02Q

Piston ring end gap

Groove 1

mm

0,20...0,40

Groove 2

mm

0,40...0,60

Groove 3

mm

0,20...0,40

Repair materials

Number

Designation

Order number

BR00.45-Z-1028-04A

Assembly cleaner

A 000 986 56 01