Toothed Belt

Toothed Belt

Special tools, testers and auxiliary items required

• Diesel Injection Pump Locking Pin (3359) (quantity: 2)

• Crankshaft Stop (T10050)

• Counter-Holder Tool (T10172)

• Special Wrench, Long Reach (T10264)

• Locking Tool (T10265)

• Socket Insert XZN 10 (T10385)

Removing

- Remove the engine cover - arrows -.





- Remove the right front wheel.





- Remove the noise insulation - 1 -.

- A3 Cabrio: Remove the noise insulation frame - arrow -.





- Disconnect the connector - 2 - on exhaust pressure sensor 1 (G450).





• Ignore - 1 -.

- Remove bolt - 1 -.





- Move the filler tube and windshield wiper fluid reservoir filler tube - 2 - to the side.

• Ignore - 3 -.

• The installation location is shown with the fuel filter removed.

- Disengage the fuel hose - 2 - from the bracket.





- Removed the bracket for the fuel lines - arrow - and move it to the side.

- Disconnect the connector - 1 - on the auxiliary fuel pump (V393).

- Remove the bolts - 3 - then remove the bracket and the auxiliary fuel pump and move them to the side.

- Loosen bolt - 1 -.





- Remove bolts - 2 - and nut - 3 -.

- Remove the hose bracket - 4 - from the fuel filter and then move the fuel filter - 7 - to the side with the fuel hoses - 5 - and - 6 - still connected.

- Disconnect electrical connector - 3 - on engine coolant temperature sensor on radiator (G83).





- Remove nut - 1 - and bolt - 2 -.

- Move the right coolant pipe to the side with the coolants hoses still connected - arrows -.

- Open the clamps - arrows - and remove the upper toothed belt guard.





- Remove the front section of the right front wheel housing liner.





- Remove vibration damper. Refer to => [ Vibration Damper ] Service and Repair.

• The ribbed belt tensioning damper is not secured.

- Remove bolts - arrows -.





- Remove the lower and center toothed belt guard.


Components could be destroyed by the toothed belt jump off.

• Only rotate the crankshaft in the direction of engine rotation.

- Turn the crankshaft at the toothed belt gear bolt until the camshaft toothed belt gear is at TDC.

• The toothed segment - arrow - must point upward.





- Secure the camshaft hub with the (3359).

• The camshaft toothed belt gear is shown in the illustration without the toothed belt.

• Ignore - 1 -.

- Secure the crankshaft toothed belt gear using the (T10050).





• The markings on the toothed belt gear - 2 - and on the crankshaft stop - 1 - must align - arrow -. The tab of the crankshaft stop must engage in the bore of the sealing flange.

• The crankshaft stop can be pushed onto the toothed belt gear only from the front side of the splines.

- Loosen the bolts - 1 - for the camshaft toothed belt gear approximately 90°.





• Disregard - arrow -.

- Remove bolt - 1 - for coolant pipe.





- Loosen the bolts - 2 - for the high pressure pump toothed belt gear approximately 90° using the (T10385).

- Loosen the nut - 1 - for the tensioning roller.





- Turn the tensioning roller eccentric pulley counter-clockwise using the (T10264) - arrow - until the roller can be secured with the (T10265).

- Then turn the tensioning roller eccentric pulley clockwise all the way using the (T10264) - arrow - and tighten the nut - 1 - hand-tight.






A used toothed belt could be destroyed if the running direction is reversed.

• Before removing the ribbed belt, mark the running direction with chalk or a felt-tip pen for installation later.

- Remove the toothed belt from the idler roller and then from the remaining toothed belt gears.

Installing (Adjusting valve timing)

• Tightening specifications, refer to => [ Toothed Belt Assembly Overview ] Toothed Belt Assembly Overview.

• The engine must be cold when adjusting the toothed belt.


Risk of damaging valves and piston crowns.

• If camshafts are being rotated, crankshaft may not rest with any piston at TDC.

Requirements

• The tensioning roller is secured by the (T10265) and fastened to the right stop by the nut.





• Secure the camshaft hub with the (3359).





• The bolts - 1 - are installed loose.

• It must still be possible to rotate the camshaft toothed belt gear and it must not tip.

• Disregard - arrow -.

• Secure crankshaft using the (T10050).





• Secure the hub on the high pressure pump with the (3359).





• The bolts - 1 - are installed loose.

• It must still be possible to rotate the high pressure pump toothed belt gear and it must not tip.

• If necessary, turn the hub on the high pressure pump by the bolt heads - 1 - with a screwdriver until it is possible to secure the hub with a locking pin.





- Turn the camshaft toothed belt gear and the high pressure pump toothed belt gear all the way clockwise by the oblong holes.





- Mount the toothed belt in the following sequence:

1. Crank shafts - toothed belt gear

2. Tensioning roller

3. Camshaft toothed belt gear

4. Coolant pump toothed belt gear

5. Toothed belt gear for the high pressure pump

6. Idler roller

- Loosen nut - 1 - on the tensioning roller and remove the (T10265).





• Disregard - arrow -.

• Make sure the tensioning roller is properly positioned in the rear toothed belt guard - arrow -.





- Mount the (T10172) on the camshaft toothed belt gear as illustrated.





- Press the counterhold tool counter-clockwise - arrow - and hold it at pre-load.

- Tighten the bolts - 1 - for the camshaft toothed belt gear and the bolts - 2 - for the high pressure pump toothed belt gear in this position.

• Tightening specification: 20 Nm.

- Carefully turn the tensioning roller eccentric pulley clockwise - arrow - with the (T10264) until the indicator is located centrally in the gap of the base plate - 2 -.





• The nut - 1 - must not turn with it.

- Hold the tensioning roller in this position and tighten the nut.

- Remove the (3359) and the (T10050).

Check the Valve Timing


Components could be destroyed by the toothed belt jump off.

• Only rotate the crankshaft in the direction of engine rotation.

- Turn the crankshaft by the toothed belt pulley bolt 2 turns in the direction of engine rotation until the crankshaft is once again just before TDC.

- Mount the (T10050) on the crankshaft toothed belt gear.





- Turn the crankshaft in direction of engine rotation, until the tip - arrow - on the crankshaft stop fits into the sealing flange.

• It must be possible to secure the camshaft hub with the (3359).





• Ignore - 1 - and - arrow -.

• It is very difficult to find the locking point on the high pressure pump hub. A small deviation - arrow - does not affect engine operation.





• The pointer on the tensioning roller - 2 - must be in the middle between the tabs - 1 - and - 3 - on the plate.





• Permissible lateral offset: maximum 5 mm.

• If the conditions are not met, correct the valve timing.

• If the conditions are met, then continue with the correct valve timing.

Correcting the Valve Timing

- If it is not possible to secure the camshaft hub, pull back the (T10050) until the hole opens.

- Turn the crankshaft opposite the direction of engine rotation just past TDC.

- Slowing turn the crankshaft in the direction of engine rotation until the camshaft hub is secured.

- Loosen the bolts on the camshaft toothed belt gear.

A - The tip of the (T10050) is just left of the hole:





- Turn the crankshaft in direction of engine rotation, until the tip - arrow - on the crankshaft stop fits into the sealing flange.

- Tighten the camshaft toothed belt gear to 20 Nm.

B - The tip of the (T10050) is just right of the hole:

- Turn the crankshaft just a little opposite the direction of engine rotation.

- Turn the crankshaft again in direction of engine rotation, until the tip on the crankshaft stop fits into the sealing flange.

- Tighten the camshaft toothed belt gear to 20 Nm.

Continue if the Valve Timing is Correct

- Remove the (3359) and the (T10050).

- Turn the crankshaft by the toothed belt pulley bolt 2 turns in the direction of engine rotation until the crankshaft is once again just before TDC.

- Check the valve timing once again.

- If it is now possible to secure the camshaft hub then tighten the camshaft toothed belt gear bolts - 1 - all the way - 8 - => [ Bolt ] Toothed Belt Assembly Overview.





- Tighten the bolts for the high pressure pump toothed belt - 2 - all the way.

- Check the valve timing once again.

Assembling

• Tightening specifications, refer to => [ Toothed Belt Assembly Overview ] Toothed Belt Assembly Overview.

• Tightening specifications, refer to => [ Lower Toothed Belt Guard and in the Center - Tightening Specification ] Toothed Belt Assembly Overview

Assembly is performed in reverse order of removal, note the following:

• Replace the seals

• Secure all hose connections with hose clamps appropriate for the model. Refer to the electronic parts catalog ETKA.

- Install vibration damper. Refer to => [ Vibration Damper ] Service and Repair.

- Install the front section of the front wheel housing liner.

- Install right coolant pipe. Refer to => [ Right Coolant Pipe ] Right Coolant Pipe.

- Install the fuel filter.

- Install the auxiliary fuel pump (V393).

- Install the windshield wiper fluid reservoir filler tube.

- Install the noise insulation.