Pinion Shaft, Adjusting
Pinion shaft, adjusting
(Adjusting pinion shaft and hollow shaft)
Special tools and equipment
^ VW 385 Universal measuring set
^ VW 387 Universal dial gauge bracket
^ VW 402 Thrust plate
^ VW 407 Press tool
^ VW 771 Multipurpose tool
^ 3062 Press disk
Special tools and equipment
^ 3114/2 Straightening tool
^ 3116 Clamping sleeve
^ VAG 1331 Torque wrench
It is only necessary to readjust the pinion shaft as described below when the gear set, pinion shaft and transmission housing tapered roller bearings have been replaced.; Refer to Adjustment overview.
Determining total shim thickness S_total (S3 plus S4)
(Adjusting pinion shaft tapered roller bearings preload).
- Differential removed
- Tighten pinion shaft -A- in vice with protective jaws.
- Insert tapered roller bearings with grease and assemble pinion shaft and hollow shaft.
- Turn hollow shaft against pinion shaft 5 revolutions in each direction so that tapered roller bearing settles.
- Preload pinion shaft/hollow shaft to 10 Nm while holding hollow shaft tightly.
- Install large tapered roller bearing outer race without shims in transmission housing.
- Press small tapered roller bearing outer race with 1.00 mm thick temporary shim S4* into gear carrier to stop.
Note: As a test requirement, a shim S4 of 1.00 mm is temporarily installed. It is referred to as S4 below. After the dimension "e" is determined, S4 is replaced with final shim S4.
- Insert completely assembled pinion shaft into transmission housing.
- Mount gear carrier with dowel sleeves and tighten bolts to torque.
- Turn pinion shaft with hollow shaft 8 revolutions in each direction before each measurement so that tapered roller bearings settle.
- Mount measuring tools.
Note: Use a 30 mm dial gauge extension.
- Place dial gauge extension on center of measuring plate VW 385/17.
- Set dial gauge (3 mm measuring range) to zero with 2 mm preload.
- Move differential up and down without turning it, note play indicated on dial gauge and record it. (Example: 0.90 mm)
Note: Turn the pinion shaft and hollow shaft before each measurement so that the result is not falsified.
The specified bearing preload is obtained by adding a constant preload figure of (0.15 mm) to the measured value (0.90 mm) and the thickness of the shim installed S4* (1.00 mm).
S_total = S4 + measured value + preload
Example:
Determining temporary shim "S3" thickness
Temporary shim S3* = S_total - S4*
Example:
- Remove large tapered roller bearing outer race, insert temporary shim S3 in transmission housing and reinstall outer race.
- Install completely assembled pinion shaft in transmission housing again.
- Mount gear carrier with dowel sleeves and tighten bolts to 25 Nm.
- Turn pinion shaft with hollow shaft 8 revolutions in each direction before each measurement so that tapered roller bearings settle.
Determining dimension "e"
- Set universal mandrel VW 385/1 setting ring to dimension a = 65 mm.
- Set sliding positioning ring to dimension b = 55 mm.
- Assemble universal measuring tool as shown in illustration. Dial gauge extension VW 385/15 = 9.3 mm. Set universal gauge VW 385/30 to Ro = 59.65 mm and attach checking mandrel.
- Set dial gauge (3 mm measuring range) to zero with 2 mm preload.
- Place end measuring plate VW 385/17 on face of pinion shaft.
- Remove master gauge and insert measuring measuring tool in housing with centering disc VW 385/3 facing final drive cover.
- Install final drive cover and tighten 4 bolts to 25 Nm.
- Using sliding setting ring, pull 2nd centering disc VW 385/2 outward until checking mandrel can still just be turned by hand.
- Turn checking mandrel until dial gauge extension makes contact with end measuring plate and indicates maximum deflection (return point). Measured value is dimension "e".
Example:
0.16 mm (red number range)
Measurement in the following example: "e" = 0.16 mm (red number range)
Determining shim "S3" thickness
S3=S3 +r+e
("e" in black number range)
S. =S*+r e
("e" in red number range)
Note:
^ The deviation "r" in respect to master gauge "Ro" is measured for the gear sets supplied as replacement parts and is given on the outer circumference of the ring gear.
^ If the measurement is in the red number range, the measurement "e" must be subtracted.
^ If the measurement is in the black number range, the measurement "e" must be added.
Example:
Note: Determine shims according to parts Supplier.
Shims available for S3
Different tolerances make it possible to select the exact thickness of shim(s) required.
Determining shim "S4*" thickness
S4 = S_total - S3
Example:
Note: Determine shims according to parts Supplier.
Shims available for S4
Different tolerances make it possible to select the exact thickness of shim(s) required.
Check measurement - checking dimension "r"
- Install pinion shaft with measured shims S3 and
S4 and turn in both direction several times.
- Insert universal measuring tool and measure dimension "r".
If correct shims have been selected dial gauge must now indicate mark dimension "r" (reading counter-clockwise on red scale) within a tolerance of + 0.04 mm.
Moment of friction (checking)
Note: Pinion shaft roller bearings are low friction bearings. Therefore, the moment of friction is of limited value as a reference value. The only possible assurance of correct running is by determining the total shim thickness S_total.
- Install these bearings as supplied and do not oil.
- Measure friction torque.
- A- = torque gauge 0 - 600 Ncm, commercially available