Pinion Shaft, Adjusting
Notes:
- Adjust the ring gear before adjusting the pinion shaft total shim thickness Stotal for shims S1 + S2), Refer to Ring Gear Adjusting.
- The pinion shaft only has to be readjusted if the final drive gear set (pinion shaft and ring gear), tapered roller bearings for pinion shaft or the final drive housing are replaced, Refer to List of Adjustments.
- Do not additionally oil new tapered roller bearings for the friction torque measurement. The bearings have already been treated with a special oil by the manufacturer.
Determine thickness of shim "S3"
Setting preload of tapered roller bearing for pinion shaft
- Mount rear final drive to repair stand.
- Install large tapered roller bearing outer race into housing without shim.
Note: The marking "Oben" on 3253/4 thrust piece faces the nut of the puller.
- Install small tapered roller bearing outer race into housing.
- Lubricate outer race with oil and install using VW408A punch and 30205 thrust pad.
- Insert pinion shaft without spacer sleeve.
WARNING: Wear protective gloves.
- Heat tapered roller bearing inner race to approx. 100° C (212° F) and install onto pinion shaft.
Notes:
- Do not additionally oil new tapered roller bearings for friction torque measurement. The bearings have already been treated with a special oil by the manufacturer.
- Install spacer sleeve only for final friction torque measurement (after determining shim S3).
- Bolt on 3304 bracket with two hex head bolts M8 x 30.
- Differential must be supported when tightening nut (e.g. using VAG 1 359/2 universal mount and transmission hoist VAG1383A).
- Replace pinion shaft nut.
- Tighten pinion shaft nut, until no play can be felt on pinion shaft.
- Increase tightening torque until specified friction torque is attained, measuring friction torque several times during this process.
A - Torque gauge, 0 - 600 Nm (commercially available)
B - Socket extension, 36 mm
- Adjust friction torque as follows:
1) Must have run at least 50 km (30 miles)
Note: If the specified friction torque is exceeded, the spacer sleeve must be replaced and the adjustment repeated.
A spacer sleeve that has been over compressed at any time cannot be reused.
- Set adjustment ring of VW385/1 universal mandrel.
Dimension -a-: 60 mm (2.36 inch)
- Set sliding adjustment ring.
Dimension b: 55 mm (2.16 inch)
- Assemble universal mandrel as illustrated:
VW385/15 dial indicator extension = 9 mm long
- Set VW 385/30 master gauge adjustable.
Ro=57.50 mm(2.266 inch)
- Set dial indicator (3 mm measuring range) to "O" with 2 mm preload.
Note: Before carrying out the measurements turn pinion shaft at least five turns in both directions, so that the tapered roller bearings settle. Otherwise a false reading will be obtained.
- Place VW 385/33 end dimension plate onto pinion shaft head.
- Remove master gauge-adjustable and insert measuring mandrel in housing. 385/3 centering disc faces final drive cover
- Install final drive cover and tighten 4 bolts.
- By turning adjustable ring, move 2nd centering disc out until mandrel can still just be turned by hand.
Determining measurement "e"
- Turn mandrel until dial indicator point touches end measuring plate on pinion shaft head, then measure maximum runout (return point). Measured value is dimension "e"(red scale).
Measurements in the example: e = 1.60 mm
Note: Dimension "e" is required to determine thickness of shim S3.
- After removing universal mandrel, and with VW385/30 master gauge-adjustable in place, check once again whether dial indicator reads "O" with 2 mm preload, otherwise repeat measurement.
Determining shim thickness "S3"
Formula:
Example:
The shims are available for "S3"
- Remove universal mandrel.
- Remove pinion shaft and large tapered roller bearing outer race and install together with measured shims S3 and spacer sleeve, Refer to Differential Assembly, Service and Repair.
- Install small tapered roller bearing inner race and tighten nut for pinion shaft until specified friction torque is obtained, Refer to Differential Assembly, Service and Repair.
Notes:
- Do not additionally oil new tapered roller bearings for the friction torque measurement. The bearings have already been treated with a special oil by the manufacturer.
- Increase tightening torque gradually and check friction torque at regular intervals, if the specified friction torque is exceeded, the spacer sleeve must be replaced and the adjustment repeated. A spacer sleeve that has been over-compressed at any time cannot be reused.
- Adjust to the friction torques:
Checking measurements
Checking dimension "r"
- Turn pinion shaft at least 5 turns in both directions.
- Insert universal mandrel and carry out check measurement.
If the shims have been correctly selected, the dial indicator should now display the value of "r" as marked on the ring gear, reading counterclockwise (red scale), within a tolerance of 0.04 mm.
- Secure pinion shaft nut using mandrel.