Timing belt drive — removal, adjustment and installation (Audi A4 B8)

Toothed belt drive

1. Timing belt: Before removing, mark the direction of rotation with chalk or a felt-tip pen; check for wear.
2. Intermediate roller.
3. Nut: 20 Nm.
4. Tension roller.
5. Nut: 20 Nm + 45°.
6. Bolt: 20 Nm.
7. Intermediate roller.
8. Bolt: 25 Nm.
9. Camshaft timing belt gear.
10. Bolt: loosening and tightening with counter support "T10051"; 100 Nm.
11. Camshaft hub.
12. Cork.
13. Rear timing belt guard.
14. Bolt: 9 Nm.
15. High pressure pump hub.
16. Nut.
17. High pressure pump toothed belt pulley.
18. Bolt.
19. Intermediate roller.
20. Bolt: replace; 50 Nm + 90°.
21. O-ring seal: Replace.
22. Coolant pump.
23. Bolt.
24. Crankshaft timing belt pulley: There should be no oil on the mating surfaces between the timing belt pulley and the crankshaft; installation is possible only in one position.
25. Bolt: replace; loosening and tightening with counter support "3415"; thread and flange add. do not lubricate; 120 Nm + 90°.

Removal

Remove the engine cover "arrows". Release the clips "arrows", remove the toothed belt protective cover. Remove the vibration damper.

Unscrew the "arrow" bolts. Removing the lower timing belt cover.

Risk of damage due to timing belt jumping. Turn the crankshaft only in the direction of engine rotation. Rotate the crankshaft using the timing belt bolt until the camshaft is at TDC. Secure the camshaft hub with the fuel pump locking pin. injection "3359". "Arrows" should not be taken into account.

Lock the crankshaft toothed belt sprocket with the crankshaft stopper "T10050". The marks on the toothed belt pulley "2" and the crankshaft stopper "1" must be opposite each other "arrow". In doing so, the pin of the crankshaft retainer must engage in the hole of the seal. flange. The stopper can be pushed onto the sprocket only from the end face of the splines.

Loosen the camshaft timing belt sprocket arrow bolts by approximately 90°. Loosen the fuel pump timing belt pulley arrow bolts by approximately 90° using the XZN 10 "T10385" insert.

Loosen nut "1" of the tension roller. Turn the tension roller eccentric counterclockwise using the T10264 angle screwdriver so that the tension roller can be secured with the T10265 lock.

Then turn the tensioner roller eccentric with the angle screwdriver "T10264" clockwise "arrow" to the stop and tighten the nut "1" by hand. Remove the toothed belt first from the deflection roller, then from the remaining pulleys.

Installation (timing adjustment)

To perform adjustment work on timing belts, the engine must be cold. Risk of damage to valves and piston crowns. When turning the camshaft, not a single piston of the crankshaft should be at "TDC".

Conditions: the tension roller is locked with the locking tool "T10265" and fixed "1" on the right stop: fix the camshaft hub with the locking pin of the system pump. injection "3359"; tighten the "arrow" bolts by hand; the camshaft timing belt gear should still rotate, but should not wobble; the crankshaft is fixed with the crankshaft stopper "T10050".

Secure the fuel injection pump hub using the fuel injection pump locking pin. injection "3359". Bolts "1" remain loosely screwed in. The high pressure pump timing belt gear should still rotate, but should not wobble.

If necessary, rotate the high pressure pump toothed belt gear using the screwdriver "arrows" by the heads of the bolts "1" so that the hub can be locked with the locking pin.

Rotate the gears of the camshaft timing belt and the high-pressure pump in their longitudinal holes clockwise until they stop. Install the timing belt in the specified order.

1. Crankshaft timing belt pulley. 2. Tension roller. 3. Timing belt gear of the camshaft. 4. Gear of the coolant pump toothed belt. 5. Pulley of the high-pressure pump toothed belt. 6. Intermediate roller.

Loosen nut "1" of the tension roller and remove locking pin "T10265". Ignore the "arrow".

Pay attention to the proper fit of the tension roller in the rear timing belt housing "arrow".

Install the counter support "T10172" on the camshaft timing belt sprocket as shown in the figure. Turn the counter-support counterclockwise "arrow" and hold it under pre-tension. In this position, tighten the bolts "1" of the camshaft toothed belt sprocket and the bolts "2" of the high-pressure pump toothed belt sprocket. Tightening torque 20 Nm.

Now carefully rotate the tension roller eccentric using the T10264 angle screwdriver in the clockwise direction until the pointer "2" is opposite the recess in the support plate. Nut "1" must not be turned. Hold the tension roller in this position and tighten the nut. Remove locking pin "3359" and crankshaft stop "T10050".

Checking the timing phases

Turn the crankshaft only in the direction of engine rotation. Rotate the crankshaft using the timing belt bolt 2 turns in the direction of engine rotation until the crankshaft is again close to TDC. Reinsert the T10050 crankshaft stopper into the crankshaft timing belt sprocket. Rotate the crankshaft in the direction of engine rotation until. until the crankshaft stop pin "arrow" is fixed in the seal during rotation. flange.

The camshaft hub must be secured with the fuel pump locking pin. injection "3359". "Arrows" should not be taken into account. The high pressure pump hub fixing point can be very difficult to locate. However, a slight deviation of the "arrow" will not affect the engine's operation.

The tension roller pointer "2" should be located in the middle between the tongues "1" and "3" of the support plate. Lateral displacement is allowed to be maximum 5 mm.

If the conditions are not met, adjust the timing. If the conditions are met, continue with the timing adjusted correctly.

Timing phase correction

If you cannot lock the camshaft hub, remove the crankshaft stopper "T10050" enough so that the journal opens access to the hole. Turn the crankshaft counterclockwise slightly past TDC. Slowly turn the crankshaft in the direction of engine rotation until the camshaft hub can be locked. After fixing, loosen the camshaft timing belt gear bolts. The journal A of the crankshaft stopper "T10050" is located to the left of the hole: rotate the crankshaft in the direction of engine rotation until the journal "arrow" of the crankshaft stopper is fixed in the seal during rotation. flange. Tighten the camshaft timing belt sprocket bolts to 20 Nm.

The journal B of the crankshaft stop "T10050" is located to the right of the hole: first turn the crankshaft slightly against the direction of engine rotation; rotate the crankshaft again in the direction of engine rotation until the crankshaft stop journal engages in the seal during rotation. flange. Tighten the camshaft timing belt sprocket bolts to 20 Nm.

Continued with correctly adjusted timing phases

Remove the system pump lock pin. injection valve "3359" and crankshaft lock "T10050". Rotate the crankshaft by the timing belt bolt 2 turns in the direction of engine rotation until the crankshaft is again close to "TDC". Repeat the timing belt phase check. If the camshaft hub can now be locked, tighten bolts "1" of the camshaft timing belt sprocket to the specified torque. Tighten bolts "2" of the high-pressure pump toothed belt gear to the specified torque. Repeat the timing phase check.