Adjusting Drive Pinion
Adjusting Drive PinionAdjustment of the pinion/ring gear according to the following instructions will only be necessary when replacing the pinion/ring gear. Make adjustments with help of the previously determined installed position (actual distance), if other parts with influence on the drive pinion are being replaced.
Determining Total Shim Thickness S tot (S3 plus S4)
1. Install tapered roller bearing outer race without shims in transmission case or gear carrier.
2. Install completely assembled drive pinion. Mount gear carrier and tighten bolts to torque of 25 Nm (18 ft lb).
3. Turn drive pinion about 20 full revolutions by hand so that both tapered roller bearings are preloaded, while lifting and lowering drive pinion.
4. Mount gauges. Set dial gauge (3 mm range) to 0.0 with 1 mm preload. Dial gauge extension length approx. 30 mm.
5. Move drive pinion up and down. Read play on dial gauge and note the value. Do not turn drive pinion during this step to avoid wrong readings. Example: 1.30 mm.
6. Take off gear carrier again.
Determining Total Shim Thickness "S tot"(S3 plus S4)
S tot = measured value + pre-load
Pre-load = 0.30 mm (constant value)
Measured value = 1.30 mm (example)
S tot = 1.6Omm
Determining Deviation "r"
1. Install shim of determined thickness (1.60 mm in the example) behind tapered roller bearing outer race in gear carrier (S4 side). Mount gear carrier again, bolt and turn drive pinion in both directions about 20 revolutions each.
2. Adjust set ring of gauge VW 385-1 to distance "a".
3. Complete universal gauge as shown.
4. Use dial gauge extension VW 385/15 with length = 9.3 mm.
5. Set the master gauge to:
Ro = 59.65 mm (016 J/K up to Mod.'88)
Ro = 58.15 mm (016 J as from Mod. '89) and mount on the universal gauge. Set the dial gauge (3 mm range) to zero with 1 mm pre-load.
6. Move the adjustable set ring back against the stop.
7. Place gauge plate VW 385/17 (with magnet) on the pinion head.
8. Remove the master gauge and insert the universal gauge into the housing (installed position). Centering disk VW 385/2 for final drive cover.
9. Mount final drive cover carefully (do not knock, risk of gauge plate slipping). Remove the toroidal sealing ring, for practical reasons, and tighten the cover with 4 screws.
10. Pull the second centering disk outwards with the adjustable set ring so that the universal gauge can still just be turned by hand.
11. Turn the universal gauge until the dial gauge probe makes contact with the gauge plate on the pinion head and the dial indicates max.deflection (reversing point). The measured value is dimension "e" (black number scale).
For example: 0.46 mm.
Determining the thickness of shim "S3"
S3 = e + r
e = Determined value (max. dial gauge deflection)
r = Deviation (given on the ring gear in 1/100 mm or determined by measuring the actual distance)
Example:
Value indicated on the dial gauge "e" 0.46 mm
Deviation value given on the ring gear "r" +0.18 mm
Shim thickness S3 = 0.64 mm
S3 shims available as spare parts:
Thickness (mm)
0.20
0.25
0.30
0.35
0.40
0.65
0.90
1.15
Note: Any thickness for "S3" is possible due to the tolerances of the shims. Measure shim thickness at many different points with a micrometer. Also check shims for burrs or damage. Only install shims in perfect condition.
Determining Thickness of Shim "S4"
S4 = S tot-S3
Example:
Total shim thickness 1.60 mm
Shim thickness S3 - 0.64 mm
Shim thickness S4 0.96 mm
Available shims S4
Thickness (mm)
0.24
0.27
0.30
0.33
0.36
0.39
0.42
0.45
0.69
0.93
1.17
1.41
Measure thickness of shims at many different points with a micrometer. Also check shims for burrs or damage. Only install shims in perfect condition.
Checking Distance "E"
1. Install drive pinion with measured shims S3 and S4. Bolt gear carrier and turn drive pinion in both directions about 20 full revolutions by hand so that the tapered roller bearings will be loaded by the rotation and can settle.
2. Apply universal gauge and check distance.
3. When shims have been selected correctly, the dial gauge (read counterclockwise - red number range) should display the value of deviation "r" inscribed on the ring gear with a tolerance of + 0.04 mm.
Checking Pre-load of Tapered Roller Bearing on Drive Pinion
A=Torque meter, standard, 0.. .600 Ncm
Screw bolt in drive pinion. Apply torque meter and read friction torque.
For new bearings it should be 200 to 400 Ncm or 30 to 60 Ncm for used bearings.
Note: Lubricate bearings with hypoid gear lube.