Overhaul

Piston Ring

Special tools, testers and auxiliary items required

• Torque wrench (V.A.G 1410)

Observe notes. Refer to => Air Supply Unit Assembly Overview.


• Do not clean air supply unit using chemical cleaning agent or high-pressure cleaner.

• Clean air supply unit using lint-free rag.

• Make absolutely sure that no dirt enters the open air lines/air line connections, connectors and electrical connections.

Removing

- Remove air supply unit without solenoid valve block. Refer to => [ Air Supply Unit, without Solenoid Valve Block ] Air Supply Unit, without Solenoid Valve Block.

- Disengage connector - arrow - and disconnect it.





- Remove cable - 1 - from clip - arrow -.





- Remove bolts - arrows -.





- Remove cylinder head from piston and lay aside both components next to another.





• Make absolutely sure that the air line - 1 - is not damaged.

- Remove gasket - 1 - and clean contact surface on cylinder head.





- Pull piston - 2 - in - direction of arrow - toward TDC (Top Dead Center).

- Remove piston ring - 3 - from piston - 2 - without equipment, e.g. screwdriver.

Installing

- Place new piston ring onto piston, gap - arrow A - on piston ring must point toward outside.





• Gap - arrow A - and anti-twist mechanism - arrow B - must align.

• Piston ring is properly installed if anti-twist mechanism is visible in gap on piston ring - arrow C -.

• Make sure not to overstretch piston ring.

• Check piston ring play, piston ring must be able to be easily turned in both directions within anti-twist mechanism in gap of piston ring - arrow C - while doing so.

- Insert new gasket - 1 -.





- Push piston - 2 - with piston ring - 3 - opposite to - direction of arrow - toward BDC (Bottom Dead Center).

- Assemble upper and lower part, piston - 1 - must slip into cylinder head - 2 - while doing so.





Tab - arrow A - must be inserted into recess - arrow B -. They serve as an anti-twist mechanism.

- Retainers - 1 - must be positioned between upper part and lower part and at white markings of air line.





- Tighten bolts - arrows - to tightening specification.





- Clip cable - 1 - in clip - arrow -.





- Connect connector - arrow -.





- Install air supply unit. Refer to => [ Air Supply Unit, without Solenoid Valve Block ] Air Supply Unit, without Solenoid Valve Block.

Tightening Specifications