AR35.31-P-0550-25T Measuring Gear Backlash Between Crown Wheel and Pinion and Correcting If Necessary

AR35.31-P-0550-25T Measuring gear backlash between crown wheel and pinion and correcting if necessary
- Rear axle center assembly dia. 198 [models 171.456, 211.056/256 up to 31.5.06, 211.065/082/087]

Test Values For Rear Axle Differential:

Special Tools:

Component Identification:

1 Insert and clamp backlash measuring instrument (037) with dial gauge in right-hand bore in differential housing.
2 Set dial gauge to "0" with 3 mm preload.
3 Hold drive pinion at joint flange and press crown wheel up and down while reading off the gear backlash.
4 Carry out measurement 4 times. Turn the ring gear approx. 90 degrees further each time.

The adjustment of the tapered roller bearings and gear set is OK if the spread dimension (expansion) of the rear axle housing and the gear backlash are within the range of the specifications. If these values are not achieved, the adjustment must be repeated using thinner or thicker locking rings as appropriate.

5 Remove backlash measuring instrument (037).

1st example

Measurement: The gear backlash is correct but the expanded dimension of the rear axle housing is too low, e.g. 0.05 mm measured expanded dimension value.

Correction: Mount a 0.05 mm thicker shim on both sides, in the process the gear backlash can change slightly!

2nd example

Measurement: The expanded dimension is correct, but the gear backlash is too large. Correction: On the left assembly side a circlip which is thinner by the missing amount is to be installed.

Install a thicker locking ring on the right-hand side (crown wheel side).

If the gear backlash is too low, proceed in the opposite manner.