Volkswagen 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 regulating valve -VAS 6342-

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

t	Dial gauge -VAS 6341/1-

t	Extension, 30 mm -VAS 6341/3-

t	Flat probe -VAS 6341/4-

Note t  This procedure is used to adjust the vacuum unit. When checking already adjusted vacuum units the values can differ. t  The vacuum unit must only be adjusted when the linkage has been loosened. t  Adjustment is carried out when turbocharger is removed.

–  Pull hose -arrow- from vacuum unit on turbocharger. –  Detach locking plate above turbocharger linkage.

–  Slacken lock nut -2-.

–  Pre-adjust bypass flap -1- above rod of vacuum unit -arrow-, so that the bypass flap can just be turned by hand. –  Tighten lock nut hand-tight.

–  Connect up hand-operated vacuum pump -VAS 6213-, turbocharger tester -V.A.G 1397A- (connection II) and pressure control valve -VAS 6342- as shown in illustration. –  Close pressure control valve -VAS 6342- at lever -1-.

–  Move slide ring -1- on hand vacuum pump -VAS 6213- to position -B- for „pressure“. –  Switch on turbocharger tester -V.A.G 1397A- and set sliding switch to position II.

–  Secure universal dial gauge bracket -VW 387- to turbocharger -arrows-. –  Secure dial gauge -VAS 6341/1- with dial gauge extension, 30 mm -VAS 6341/3- and flat pickup -VAS 6341/4- to universal dial gauge bracket -VW 387-. –  With pressure at 0 bar, set dial gauge -VAS 6341/1- to 1 mm preload. –  Turn dial of dial gauge -VAS 6341/1- to 0. –  Make sure that dial gauge can move freely. –  Operate vacuum pump -VAS 6213- until turbocharger tester -V.A.G 1397A- indicates 350 +/- 5 mbar. –  The dial gauge must indicate 4.1 mm to 4.3 mm, otherwise turn rod of vacuum unit until the value is indicated. –  Tighten lock nut hand-tight. –  Repeat adjustment.   Note The values in mm refer to the read value (includes 1 mm pretension). –  Vent system via pressure control valve -VAS 6342- so that pressure reading drops to 0 mbar. –  Set dial gauge -VAS 6341/1- to 0.   Note The following measurements must be performed in continuous sequence. Do not allow the pressure to drop to 0 between measurements. –  Operate vacuum pump -VAS 6213- until turbocharger tester -V.A.G 1397A- indicates 350 +/- 5 mbar. –  Read off and note value indicated on dial gauge -VAS 6341/1-. –  Operate vacuum pump -VAS 6213- until turbocharger tester -V.A.G 1397A- indicates a value between 650 mbar and 700 mbar. –  Vent system via pressure control valve -VAS 6342- so that pressure reading drops to 350 +/- 5 mbar. –  Read off and note value indicated on dial gauge -VAS 6341/1-. –  Add values 1 and 2 together and divide by 2. –  The result (mean value) should be 5 +/- 0.25 mm. –  Correct setting if the result (average) is not 5 +/- 0.25 mm, tighten lock nut hand-tight and repeat measurement. –  If the result (mean value) is 5 +/- 0.25 mm, tighten the lock nut to 5 Nm and secure with sealing paint. –  Secure locking plate above turbocharger linkage.