Audi Workshop Service and Repair Manuals

Adjusting pinion shaft The pinion shaft only needs to be re-adjusted according to the following instructions if the final drive gear set, the tapered roller bearings for the pinion shaft or the rear final drive housing are being renewed → Chapter.

Special tools and workshop equipment required

t	Universal measuring tool -VW 385-

t	Engine and gearbox support -VW 540-

t	Bearing preload gauge -VAS 6222-

t	Dial gauge

t	Socket (long) -SW 36-

Determining thickness of shim "S3" l  Before adjusting pinion shaft, first determine total shim thickness “Stotal” (S1 plus S2) required for specified preload on differential tapered roller bearings → Chapter. (Setting preload of tapered roller bearing for pinion shaft) –  Clamp rear final drive in assembly stand → Fig. –  Fit both tapered roller bearing outer races without shims into housing → Fig.. t  Install new tapered roller bearings as supplied; do not lubricate additionally with oil. t  Only install spacer sleeve for final friction torque measurement (after determining shim “S3”). –  Fit pinion shaft in housing with large tapered roller bearing inner race but without spacer sleeve.

–  Heat small tapered roller bearing inner race to approx. 100°C and fit on pinion shaft.   WARNING Wear protective gloves. –  Fit propshaft flange and tighten hexagon nut for flange → Fig..

Only increase tightening torque slowly. Stop and and check friction torque several times → Anchor. Use bearing preload gauge -VAS 6222- and socket (long) -SW 36- for measuring friction torque. Set friction torque as follows:

New bearings	Used bearings → Note
150 … 200 Ncm	30 … 60 Ncm

1)  run at least 50 km (30 miles)

Determining dimension “e” –  Adjust setting ring of universal measuring tool -VW 385/1- to dimension “a” = 60 mm. –  Set the adjustable ring to dimension “b” = 55 mm.

–  Assemble universal mandrel -VW 385/1- as shown. t  Dial gauge extension -VW 385/15- = 9 mm long t  Set universal master gauge -VW 385/30- to R0 = 57.50 mm. t  Set dial gauge (3 mm measuring range) to zero with 2 mm preload. –  Turn pinion shaft at least 8 turns in both directions to settle the tapered roller bearings.

–  Place end measuring plate on face of pinion shaft.

–  Remove master gauge and insert measuring tool into housing. –  Fit cover for rear final drive and tighten 4 bolts. –  Using the adjustable ring, move the 2nd centring disc outwards as far as possible so that the measuring tool can still just be turned by hand.

–  Turn measuring tool until dial gauge extension contacts end measuring plate and gauge indicates maximum deflection (return point). The measured value is dimension “e” (in red scale). t  Example: dimension “e” = 1.60 mm Determining thickness of shim “S3” “S3” = e – r

e	-	Measured value (maximum deflection)
r	-	Allowance (marked on crown wheel in 1/100 mm)

Example:

Dial gauge reading “e”	1.60 mm
Allowance “r” marked on crown wheel	– 0.42 mm
Shim thickness “S3”	= 1.18 mm

–  Determine shim(s) as accurately as possible according to table. For Part Nos. refer to → Electronic parts catalogue. The following shims are available for “S3”

Shim thickness (mm)
0.95	1.20	1.45
1.00	1.25	1.50
1.05	1.30	1.55
1.10	1.35
1.15	1.40

–  Remove universal mandrel. –  Remove pinion shaft and outer race of large tapered roller bearing and re-install together with calculated shims “S3” and new spacer sleeve → Chapter. –  Fit inner race of small tapered roller bearing and tighten nut for pinion shaft until specified friction torque is obtained → Fig..

Only increase tightening torque slowly. Stop and and check friction torque several times → Anchor.   Caution If the specified friction torque is exceeded, the spacer sleeve must be renewed and the adjustment procedure repeated. A spacer sleeve which has been compressed too much cannot be re-used. Set friction torque as follows:

New bearings	Used bearings → Note
150 … 200 Ncm	30 … 60 Ncm

2)  run at least 50 km (30 miles)

Checking dimension “r” –  Turn pinion shaft at least 8 turns in both directions to settle the tapered roller bearings. Insert universal mandrel -VW 385/1- and measure dimension “r”. If the correct shims have been selected, the dial gauge (reading anti-clockwise in the red range), should now show the allowance “r” within a tolerance of + 0.05 mm

–  Secure hexagon nut. –  After securing the nut for the pinion shaft, measure the radial run-out at the flange for the propshaft, and mark accordingly → Chapter.