Audi Workshop Service and Repair Manuals

Adjusting vacuum unit for turbocharger

Special tools and workshop equipment required

t	Universal dial gauge bracket -VW 387-

t	Hand vacuum pump -VAS 6213-

t	Pressure control valve -VAS 6342-

t	Turbocharger tester -V.A.G 1397A-

t	Dial gauge set, 4 pieces -VAS 6341-

t	Torque wrench -V.A.G 1783-

t  Hose clip pliers -VAS 6362-

Procedure –  Pull off engine cover panel (front) -arrows- and remove towards front.

–  Remove bolts -arrows- and detach heat shield for turbocharger.

–  Remove bolts -1 and 3-. –  Release hose clip -2-, detach air pipe (top right) and remove air hose.

–  Disconnect hose -arrow- from vacuum unit.

–  Close lever -2- on pressure control valve -VAS 6342-. –  Set up measuring equipment and testers as shown in illustration and connect to connection „II“ of turbocharger tester -V.A.G 1397A- and to vacuum unit for turbocharger. –  Move adjuster ring -1- on hand vacuum pump -VAS 6213- to select „pressure“-arrow-.

–  Switch on turbocharger tester -V.A.G 1397A- and set sliding switch to position „II“.

–  Operate hand vacuum pump -VAS 6213- several times until the pressure is approx. 800 mbar.   Caution Risk of damage to vacuum unit on account of excessive pressure. The pressure must not exceed 800 mbar. –  Vent hand vacuum pump -VAS 6213--arrow A- to make sure the linkage of the charge pressure control in the turbocharger is free to move. –  Repeat procedure 5 times.   Note This procedure should prevent the bypass flap and the vacuum unit linkage from sticking.

–  Attach dial gauge -VAS 6341/1- to universal dial gauge bracket -VW 387-. –  Secure universal dial gauge bracket -VW 387- to turbocharger as shown in illustration. l  The dial gauge linkage must be in line with the linkage of the vacuum unit. –  With pressure at 0 bar, set dial gauge -VAS 6341/1- to 1 mm preload. –  Operate hand vacuum pump -VAS 6213- several times until the pressure displayed on turbocharger tester -V.A.G 1397A- is approx. 800 mbar. l  Specification on dial gauge -VAS 6341/1-: 1 mm travel –  Vent system via pressure control valve -VAS 6342- so that pressure reading drops to 0 mbar. Checking adjustment of vacuum unit –  Set scale of dial gauge -VAS 6341/1- to „0“.   Note The following measurements must be performed in the specified sequence. Do not allow the pressure to drop to 0 between measurements. –  Operate hand vacuum pump -VAS 6213- several times until a pressure of 500 ± 5 mbar is displayed on turbocharger tester -V.A.G 1397A-. –  Read off and note travel indicated on dial gauge -VAS 6341/1-. –  Operate hand vacuum pump -VAS 6213- several times until a pressure of 800 ± 5 mbar is displayed on turbocharger tester -V.A.G 1397A-. –  Vent system via pressure control valve -VAS 6342- so that pressure reading drops to 500 ± 5 mbar. –  Read off and note travel indicated on dial gauge -VAS 6341/1-. –  Determine average value: add values „1“ and „2“ together and divide by 2. l  Specification: 5.50 ± 0.25 mm.   Note

t  If reading does not match specification, loosen lock nut -1-. t  Turn nut -2- until specification is obtained. t  Tighten lock nut -1-. –  When adjustment is correct, tighten lock nut -1- and secure with sealing paint. Assembling Installation is carried out in the reverse order; note the following: Tightening torques l  → Chapter „Turbocharger - exploded view“. l  → Chapter „Charge air cooler - exploded view“.   Note t  Fit new O-rings. t  Secure all hose connections with the correct type of hose clips (same as original equipment) → Electronic parts catalogue. –  Install air pipe (top right) → Chapter. –  Install air hoses with screw-type clips → Fig..