Audi Workshop Service and Repair Manuals

Adjusting preload of ball bearing for flange shaft (left-side)   Note t  It is only necessary to optimise preload of ball bearing for flange shaft (left-side) on certain vehicles; for list of vehicles see table → Anchor. t  This measure is not required on later vehicles because of a design change. l  Flange shaft (left-side) must be removed → Chapter.

l  Mounting bracket with wear pattern „B“ → Anchor (scoring and possibly material worn down around circumference of hole). l  Mounting bracket and ball bearing must be renewed → Chapter.

Procedure –  Attach emery cloth (grain size 150) to sanding block and clean coarse dirt and corrosion off contact surface -arrow-.   Note The contact surface does not have to be ground down to bare metal; it is sufficient to remove coarse dirt and corrosion. –  Clean contact surface and bearing seat.

–  Fit new ball bearing -arrow- for flange shaft (left-side) in bearing seat. Continued procedure: t  If bearing protrudes slightly outside contact surface → Anchor t  If bearing is below contact surface → Anchor

Procedure if bearing protrudes outside contact surface –  Apply straight edge (500 mm) -VAS 6075- across bearing and measure distance to contact surface on gearbox housing on both sides using feeler gauge. –  Note down measured value. –  Re-apply straight edge at an angle of 90° across bearing and measure distance to contact surface on gearbox housing on both sides using feeler gauge. –  Note down measured value. Determining shim(s):   Note The smallest of the 4 measured values is used to determine the shim(s). l  Specification: bearing should protrude by 0.5 ... 0.8 mm

	Smallest amount of bearing protrusion (0.1 mm in this example)
+	Thickness of shim(s), (thickness 0.3 mm)
=	Bearing preload, (specification 0.5 ... 0.8 mm)

Example: 1 shim:    0.1 mm + 0.3 mm = 0.4 mm, „bearing preload insufficient“ 2 shims:    0.1 mm + 0.3 mm + 0.3 mm = 0.7 mm „bearing preload in specified range“ l  Result: Inserting 2 shims of 0.3 mm thickness gives a bearing preload of 0.7 mm (inside tolerance range of 0.5 … 0.8 mm)

Procedure if bearing is below contact surface   Note Use only the method described here to measure the distance below the contact surface. –  Apply straight edge (500 mm) -VAS 6075- across contact surface on gearbox housing and measure distance to bearing on both sides using feeler gauge. –  Note down measured value. –  Re-apply straight edge at an angle of 90° across contact surface on gearbox housing and measure distance to bearing on both sides using feeler gauge. –  Note down measured value. Determining shim(s):   Note t  The largest of the 4 measured values is used to determine the shim(s). t  The measured distance below the contact surface is taken as a minus value („–“) for the calculation. l  Specification: bearing should protrude by 0.5 ... 0.8 mm

–	Largest distance below surface (–0.15 mm in this example)
+	Thickness of shim(s), (thickness 0.3 mm)
=	Bearing preload (specification 0.5 ... 0.8 mm)

Example: 1 shim:    -0.15 mm + 0.3 mm = 0.15 mm, „bearing preload insufficient“ 3 shims:    -0.15 mm + 0.3 mm + 0.3 mm + 0.3 mm = 0.75 mm, „bearing preload in specified range“ l  Result: Inserting 3 shims of 0.3 mm thickness gives a bearing preload of 0.75 mm (inside tolerance range of 0.5 … 0.8 mm)

Continued for all vehicles: –  Renew mounting bracket, ball bearing and circlip → Chapter. –  Before installing flange shaft fit calculated number of shims -0B4 409 227--item 1- in bearing seat in gearbox. –  Install flange shaft (left-side) → Chapter.