Pinion, Adjusting

Adjusting Pinion And Hollow Shaft
Adjustment of the pinion as explained here is only necessary when the gear set has been replaced. When other parts that also influence the position of the pinion have been replaced, the setting is performed by measuring the adjustment position before removing the pinion (actual measurement). Also refer to "List of adjustments", at Pinion, Determining Installation Position.

Determining Total Shim Thickness Stotal (S3 Plus S4)
(Adjusting preload of tapered roller bearings of pinion with hollow shaft)
- Install outer races of tapered roller bearings, without shims, in transmission housing and cover.
- Always install shim (rubber) and pressure plate to measure shim thickness and to determine thickness of shim S4.
- Press double tapered roller bearing inner race onto pinion and secure.
- Install circlip for tapered roller bearing onto hollow shaft and press on tapered roller bearing






- Install needle bearing (arrow) onto the pinion shaft and install hollow shaft.
- Place pinion and hollow shaft into transmission housing.
- Install transmission cover.
- Tighten bolts to 25 Nm (18 ft lb).






- Press on head of pinion with removal tool VW 296 until outer race of tapered roller bearing makes contact with transmissian cover.
- Turn pinion and hollow shaft by hand until tapered roller bearing settles.






- Set up measuring fixture and turn dial indicator to zero, with 1 mm preload.
- Turn transmission 180° so that cover is at top.
- Turn pinion by hand until tapered roller bearing settles.

CAUTION! Before carrying out the measurement, turn the pinion and hollow shaft so that the tapered roller bearing can settle. Otherwise the measurements will be incorrect.






- Take reading on dial indicator.

Example:
Reading on dial indicator = 1.45 mm
Determine Stotal (S3 + S4).
Stotal = Gauge reading + preload
Preload (design value-constant) 0.15 mm
+ Gauge reading (example) 1.45 mm
=Stotal 1.60 mm

Checking Preload Of Tapered Roller Bearings For Pinion And Hollow Shaft
- Using calculated total thickness (Stotal, 1.60 mm in example above) select shim from table (refer below) and install behind tapered roller bearing outer race of transmission cover (S4 side).
- Install transmission cover.
- Rotate pinion and hollow shaft several times so that tapered roller bearings can settle.






- Install measuring fixture.
- Secure bolt (arrow) on transmission housing.
- Set dial indicator (3 mm range) to zero with 1 mm preload.
- Loosen bolts of transmission cover.

If shims have been selected correctly, dial indicator should now indicate a reading between 0.08 and 0.15 mm.






Measuring Friction Torque
- Leave calculated thickness of shim (1.60 mm in example) in place behind tapered roller bearing outer race in transmission cover (S4 side).
- Lubricate tapered roller bearings with gear oil.
- Install transmission cover again.
- Measure coefficient of friction of tapered roller bearings for pinion and hollow shaft.






- The illustrated friction torques should be set

Determining Dimension e
- Leave calculated thickness of shim (1.60 mm in example) in place behind tapered roller bearing outer race in transmission cover (S4 side).
- Install transmission cover again.
- Rotate pinion and hollow shaft several times so that tapered roller bearings can settle.






- Adjust setting ring of universal measuring bar VW 385/1; dimension -a- = 35 mm.
- Adjust sliding ring; dimension -b- = 75 mm.






- Set up universal measuring bar as shown.
* Ring gear diameter 170 mm: Ro = 54.95 mm
* Dial indicator extension used should be 6.5 mm (0.256 in.) long when Ro = 54.95 mm.

Set master gauge VW 385/30 as follows:
- Place on measuring bar and set dial indicator (3 mm range) to zero with 1 mm preload.






- Lay end plate VW 385/33 onto pinion head.
- Remove master gauge and insert measuring bar into housing.
Centering disc VW 385/3 faces final drive cover.
- Install final drive cover and lighten four bolts.
- Draw second centering disc out with sliding ring so far that bar can only be adjusted if turned by hand.






- Measure dimension e.
- Turn measuring bar until dial indicator tip touches end plate at pinion head and indicates max. deflection (reversal point).

The reading obtained is size e (black figure range).
Example: 0.46 mm






Arrangement Of Measuring Tools When Determining Dimension e

Determining Thickness Of Shim S3
- S3 = e + r
e - Gauge reading (max. deflection)
r - Deviation (marked on ring gear in units of 1/100 mm, or determined by actual measurement)






Example: The tolerances in nominal shim sizes make it possible to choose a shim with the precise thickness required for S3.






Available shims S3

Note: If the required thickness of shim S3 is greater than the largest shim listed in the table, two shims that combine to produce the required thickness may be installed.

Determining Thickness Of Shim S4
- S4 = Stotal - S3






Example:
- The tolerances in nominal shim sizes make it possible to choose a shim with the precise thickness required for S4.






- Available shims S4

Note: If the required thickness of shim S4 is greater than the largest shim listed in the table, two shims that combine to produce the required thickness may be installed.

Checking Measurements
Checking dimension r
- Install pinion and hollow shaft with measured size of shims S3 and S4 and turn several times in both directions.






- Insert universal measuring bar and check measurements.
If shims have been correctly selected, the dial indicator, reading counterclockwise (red gauge scale), should indicate the inscribed value of deviation r within a tolerance of ± 0.04 mm.