Pinion, Adjusting

PINION, ADJUSTING

Note: It is only necessary to readjust the drive pinion as described below when the ring and pinion set, pinion tapered roller bearings and final drive housing have been replaced.

Determining Thickness Of Shim "S3"
(Adjusting drive pinion tapered roller bearings preload)
- Insert both tapered roller bearing outer races without shims into housing.
- Install pinion with large tapered roller bearing inner race but without spacer sleeve in housing.





- Heat inner race for tapered roller bearing to 100°C (212°F) and install on pinion.

WARNING: Wear protective gloves when performing this step.

- Install driveshaft flange and tighten hex nut for flange.

Note: Increase the tightening torque slowly, while reading the turning torque several times. If the specified turning torque is exceeded, the spacer sleeve must be replaced and the adjustment repeated. A spacer sleeve that has been compressed too much cannot be used again.





A - Torque gauge, commercially available: 0 - 600 Ncm (0 - 53 inch lbs.)
B - Deep socket insert, 36 mm AF





- Set turning torque as follows:

Note: Use 3/4 inch to 1/2 inch reducer if necessary.





- Set adjusting ring of VW385/1 measuring bar to dimension "a" - 60 mm (2.36 inch).
- Set movable adjusting ring to dimension "b" - 55 mm (2.17 inch).





- Assemble universal measuring bar as shown in illustration,
VW385/15 gauge extension - 9 mm.
- Set VW 385/30 master gauge to Ro - 57.50 mm.
- Set dial indicator (3 mm measuring range) to zero with 2 mm preload.

Note: Before measuring, turn the pinion at least 5 turns in both directions, so the tapered roller bearing can settle. Otherwise, the measurement will be incorrect.





- Place VW385/33 end gauge on pinion head.





- Remove master gauge and install measuring bar in housing.
- Install final drive cover and tighten 4 bolts.
- Using sliding adjusting ring, turn 2nd centering disc far enough outward so that measuring bar can still be just turned by hand.

Determining Measurement "e"





- Turn mandrel until dial indicator pin touches end gauge on drive pinion head and measure maximum deflection (return point).
^ The measured value is dimension "e" (in red scale).
^ Example: 1.60 mm

Note: Dimension "e" is necessary for determining the thickness of shim "S3."

After removing the universal measuring bar:
- Check again to make sure dial indicator is on "0" with 2 mm pre-load, with VW385/30 master gauge installed; repeat measurement if necessary.

Determining Shim Thickness "S3"
S3 = e - R
e = value determined
R = dimension (specified on ring gear in 1/100 mm)





Example:

Note: Because of the different thicknesses of the shims, the required shim thickness for "S3" may be produced by using more than one shim.





Table Of Shims

Shims supplied as replacement parts
- Remove drive pinion and outer race of large tapered roller bearing, and install selected shim S3 and spacer sleeve.
- Install inner race of small tapered roller bearing and tighten nut for drive pinion until specified turning torque is achieved.

NOTES:
- Do not additionally treat new tapered roller bearings to measure the turning torque. For this purpose, the bearings are already pre-treated with a special oil.
- Increase the tightening torque slowly, while reading the turning torque several times. If the specified turning torque is exceeded, the spacer sleeve must be replaced and the adjustment repeated. A spacer sleeve that has been compressed too much one time cannot be used again.





Turning Torque Specifications

Carrying Out Control Measurement

Checking dimension "R"
- Turn pinion in both directions at least 5 revolutions.





- Install universal measuring bar and carry out control measurement.
If shims are correctly selected, the dial indicator, read in a counterclockwise direction (red scale range), must display the value of the dimension "R" with a tolerance of ± 0.04 mm.
- Secure pinion nut.
- Measure and mark radial runout on drive shaft flange.