Drive Pinion, Adjusting
Drive pinion, adjusting
(Adjusting drive pinion and hollow shaft)
Repairs after which the drive pinion must be adjusted, Refer to Differential Assembly, Adjustment
Special tools, testers and auxiliary items
^ Universal mandrel VW 385/1
^ Centering disc VW 385/2
^ Centering disc VW 385/3
^ Measuring plunger VW 385/14
^ Measuring plate VW 385/17
^ Master gauge VW 385/30
^ Universal dial gauge bracket VW 387
^ Press tool VW 407
^ Multi-purpose tool VW 771/15
^ Thrust pad 3062
^ Pin 3114/2
^ Clamping sleeve 3116
^ Bolt 3116/1
^ Torque gauge 0-600 Ncm
^ Dial gauge
^ Dial gauge extension 6.5 mm
^ Dial gauge extension 30 mm
Determining total shim thickness "Stotal" for shims "S3" + "S4"
(Setting preload of tapered roller bearing for drive pinion with hollow shaft)
Differential removed
- Clamp drive pinion in a vice using clamps -A-.
- Insert tapered rollers with grease, assemble drive pinion and hollow shaft.
- Turn hollow shaft against drive pinion five turns in both directions so that tapered roller bearings settle.
- Preload drive pinion/hollow shaft to 10 Nm, hold hollow shaft when doing this.
- Insert outer race for tapered roller bearing for drive pinion into transmission housing without shims, Refer to Transmission Disassembling and Assembling, Drive Pinion and Hollow Shaft, Disassembling and Assembling, See Fig. 2 and Fig. 3.
- Insert outer race for tapered roller bearing for drive pinion with shim "S4" (1.0 mm thick) into bearing plate.
Note: For measurement purposes a shim "S4" of 1.0 mm is initially inserted which is designated "S4" After determining measurement "e" "S4" will be replaced by the correct shim "S4."
- Insert completely assembled drive pinion in transmission housing.
- Fit bearing plate with dowel sleeves and tighten to 25 Nm.
- Turn drive pinion with hollow shaft five turns in both directions so that tapered roller bearings settle.
- Assemble measuring equipment, use a 30 mm dial gauge extension.
- Set dial gauge (3 mm measuring range) to "0" with 2 mm preload.
Note: The tip of the dial gauge must be positioned on center of drive pinion.
- Lift drive pinion, without turning, and read off play on dial gauge.
Measurement in example: 0.90 mm
Note: If the measurement has to be repeated, the drive pinion with hollow shaft must be turned 5 turns each direction to settle the tapered roller bearings. Set dial gauge again to "O" with 2 mm preload.
Formula: "Stotal" = "S4" + measurement bearing preload
Example:
Inserted shim "S4" 1.00 mm
+ Measured value (example) 0.90 mm
+ Bearing preload (constant) 0.15 mm
= Total shim thickness "Stotal" for "S3" + "S4" 2.05 mm
Determining thickness of shim "S3*"
Formula:
S3 = "Stotal" - "S4"
Example:
Total shim thickness Stotal for "S3" + "S4" 2.05 mm
-Inserted shim "S4" 1.00 mm
=Thickness of shim "S3" 1.05 mm
Remove outer race for tapered roller bearing, insert shim "S3*" into transmission housing and install outer race again
, Refer to Transmission Disassembling and Assembling, Drive Pinion and Hollow Shaft, Disassembling and Assembling, See Fig. 2 and Fig. 3.
- Insert completely assembled drive pinion into transmission housing again.
- Fit bearing plate with dowel sleeves and tighten securing bolts to 25 Nm.
- Turn drive pinion with hollow shaft five turns in both directions to settle the tapered roller bearing.
Determining measurement "e"
Note: Measurement "e" is required to determine the final shim thickness of "S3" and "S4. "
- Set adjustment rings of universal mandrel VW 385/1 to the following measurements:
^ Dimension a = 65 mm
^ Dimension b = 55 mm
- Assemble universal mandrel VW 385/1 as illustrated:
^ Dial gauge extension VW 385/15, 9.3 mm long
^ Master gauge VW 385/30
- Set master gauge VW 385/30 to Ro = 59.65 mm and fit onto mandrel.
- Set dial gauge (3 mm measuring range) to "0" with 2 mm preload.
Note: The gauge VW 385/27 can also be used in place of the master gauge VW 385/30 (Ro= 59.65 mm).
Arrangement of measuring equipment when determining dimension "e"
- Place end measuring plate VW 385/17 onto drive pinion head.
Note: Ensure plate contact surface fits exactly and is free of oil.
- Take master gauge off mandrel.
- Insert mandrel into transmission housing.
^ The centering disc 385/3 faces toward cover for final drive
- Fit cover for final drive and tighten 4 bolts to 25 Nm.
- Using adjustable ring, pull 2nd centering disc VW 385/2 out as far as possible so that mandrel can still just be turned by hand.
- Turn mandrel until dial gauge plunger tip touches end measuring plate on drive pinion head, then measure maximum deflection (return point).
^ Measurement in following example: "e" = 0.16 mm (in red scale)
Determining thickness of shim "S3"
Formula:
"S3" = "S3*" + "r" ^"e"
("e" in black scale)
or
"S3" = "S3*" + "r" - "e"
("e" in red scale)
Note:
^ The deviation "r" related to the master gauge "Ro" is measured for the final drive sets supplied as replacement parts and inscribed on outer circumference of ring gear.
^ If measurements are obtained on red scale then subtract value "e."
^ If measurements are obtained on black scale then add value "e."
Example:
Inserted shim "S3* "1.05 mm
+ Deviation "r "0.38 mm
- Determined "e" (in red scale) 0.16 mm
= Thickness of shim "S3 " 1.27 mm
- Determine shim(s) from table.
Refer to Parts Supplier
The following shims are available for "S3"
1) Using the shim tolerance variations it is possible to find the exact shim thickness required, insert two shims if necessary.
Determining thickness of shim "S4"
Formula: S4 = Stotal - S3
Example:
Total shim thickness Stotal
for"S3" + "S4 "2.05 mm
-Thickness of shim "S3 "1.27 mm
=Thickness of shim "S4 "0.78 mm
- Determine shim(s) from table.
Refer to Parts Supplier
The following shims are available for"S4"
1) Using the shim tolerance variations it is possible to find the exact shim thickness required, insert two shims if necessary.
Performing check measurement
Checking dimension "r"
- Install drive pinion with determined shims "S3" and "S4" and turn 5 turns in both directions.
- Insert universal mandrel,Refer to Drive Pinion, Adjusting"determining measurement 'e"' end perform check measurement.
- Read off dial gauge anti-clockwise (red scale).
^ If the shims have been correctly selected, the deviation "r" (marked on outer circumference of ring gear) must be shown - within a tolerance of = 0.04 mm
Note: Then, (after removing universal mandrel) check again that the dial gauge, with master gauge VW 385130 in place, indicates "0" with 2 mm preload, otherwise correct adjustments.
Measuring friction torque (check)
Note:
^ Drive pinion/hollow shaft tapered roller bearings are low friction bearings. Therefore the frictional torque has only a limited use as a check. Correct adjustment is only possible by determining the total shim thickness "Stotal".
^ Do not additionally oil new tapered roller bearing to perform the Fictional torque measurement. These bearings have already been treated with a special oil by the manufacturer.
- Fit torque gauge 0-600 Ncm -A- onto drive pinion.
B - Socket
- Insert tensioning sleeve 3116.
Frictional torque specification: