Pinion, Adjusting

PINION, ADJUSTING








Special tools and equipment
^ VW385 Universal mandrel
^ VW540 Holding fixture

It is only necessary to readjust the pinion as described below when the pinion and ring gear (pinion set), pinion tapered roller bearings or final drive housing have been replaced; refer to Adjustment Overview.

Determining thickness of shim "S3"
(Adjusting pinion tapered roller bearings preload).
- Install both tapered roller bearing outer races without shims into housing. Service and Repair
- Install pinion in final drive housing with large tapered roller bearing inner race but without spacer sleeve.





- Heat small tapered roller bearing inner race to approx. 100°C and install onto pinion.
- Install drive flange and tighten nut for flange. Service and Repair

Note: Increase tightening torque slowly and check friction torque at regular intervals. If the prescribed friction torque is exceeded, the spacer sleeve must be replaced and the adjustment repeated. A spacer sleeve which has been compressed too much cannot be reused.





Use commercially available torque gauge -A-, 0-600 Ncm (approx. 0-53 inch lbs.)
B - Deep socket insert, 36 mm

Set friction torque as follows
New bearings: 200 - 250 Ncm (18 - 22 inch lbs.)
Used bearings (1): 30 - 60 Ncm (3 - 5 inch lbs.)
(1) Run at least 50 km (30 miles)

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





- Set setting ring of VW385/1 measuring bar to 60 mm (dimension -a-).
- Set sliding positioning ring to 55 mm (dimension -b-).





- Assemble measuring bar as shown in illustration.
^ VW385/15 extension pin = 9 mm.
^ VW385/30 master gauge-adjustable to Ro = 57.50 mm.
- Set dial indicator (3 mm measuring range) to zero with 2 mm preload.
- Turn pinion at least 8 turns in both directions so that tapered roller bearings settle.





- Place end gauge on face of pinion.





- Remove master gauge and insert measuring mandrel in housing.
- Install final drive cover and tighten 4 bolts.
- Use sliding setting ring to pull 2nd centering disc outward until mandrel can still just be turned by hand.

Determining dimension "e"





- Turn mandrel until measuring extension makes contact with end measuring plate and indicates max. deflection (return point).
^ Measurement achieved is dimension "e" (red scale range)
^ Example: 1.60 mm

Determining shim thickness "S3"
S3 = e - r
e = calculated value (max. deflection)
r= dimension (given in 1/100 mm on ring gear)





Example

Different tolerances make it possible to select the exact thickness, of shim(s) required.





Table of shims

- Remove universal mandrel.
- Remove pinion and large tapered roller bearing outer race and install shim calculated for S3 and spacer sleeve. Service and Repair
- Install small tapered roller bearing inner race and tighten nut for pinion to specified friction torque. Service and Repair

Note: Increase tightening torque slowly and check friction torque at regular intervals. If the prescribed friction torque is exceeded, the spacer sleeve must be replaced and the adjustment repeated. A spacer sleeve which has been compressed too much cannot be reused.

Set friction torque as follows
New bearings: 200 - 250 Ncm (18 - 22 inch lbs.)
Used bearings (1): 30 - 60 Ncm (3 - 5 inch lbs.)
(1) Run at least 50 km (30 miles)

Carry out check measurement - checking dimension "r"
- Turn pinion at least 8 turns so that tapered roller bearings settle.





Install universal mandrel and measure dimension "r."
With correctly selected shims the dial indicator, reading counter clockwise (red number range), must indicate the value of the noted deviation "r" within a tolerance of + 0.05 mm.
- After nut for pinion is secured measure radial run-out on drive flange and mark. Testing and Inspection