1. After blocking the front wheels, jack up the rear of the car and place it on supports, placing them below the frame being unscrewed in front of the rear springs. Support the weight of the rear axle with a jack placed under the differential housing.
2. Remove both rear axle half shafts as described in Section 9.
3. Mark the relative positions of the propeller shaft and the rear axle drive pinion flange, then unscrew the bolt and separate the propeller shaft from the flange. Place the shaft aside. Please note that new bolts will be required for installation.
4. Using a preload gauge, determine the torque required to turn the pinion gear and record it (see Figure 12.4).
Figure 12.4. Torque wrench for determining the torque required to turn the main drive pinion.
5. Using a suitable tool with a fork on the end (or rod), screwed to the holes of the gear flange, hold the flange stationary and unscrew the lock nut (see Figure 12.5). Please note that a new lock nut will be required during installation.
Figure 12.5. Fork-shaped device used to hold the flange when loosening the gear lock nut.
6. After marking the position of the gear flange relative to the gear shaft, remove the flange, using a puller if necessary.
7. Carefully pry up the old oil seal with a blunt screwdriver or similar tool, then clean out the oil seal location in the differential housing.
8. Place the new oil seal into the differential housing, after lubricating the mating surfaces of the seal and housing. The contact lips of the oil seal must face inward.
9. Using a soft metal pipe of suitable diameter, carefully guide the new oil seal into the recess in the differential housing until the face of the seal is flush with the housing. During this operation, be careful not to hit the end of the pinion shaft.
10. Lubricate the contact lips of the oil seal and the working surface of the drive gear flange, then install the flange in its original position on the gear grooves.
11. Install the new lock nut and tighten it gradually, little by little. Check the preload sensor gear torque at regular intervals during the tightening process. When tightening the nut, hold the gear flange from rotating as described in paragraph 5.
12. After tightening the nut to the previously noted torque value, rotate the gear a few times to seat the bearing, then tighten the nut to an additional torque of 0.3 N·m. This additional tightening is required to compensate for the additional friction of the new oil seal. For example, if the original value noted when removing (paragraph 4), if the calculated torque was 2.2 N·m, then adding a compensating correction for the new oil seal of 0.3 N·m, we obtain the final torque value, which in this case is 2.5 N·m. It is extremely important that the calculated torque is not exceeded for the reasons noted above (see the introductory paragraph at the beginning of this Section).
13. After connecting the cardan shaft, make sure that the marks made earlier match. Tighten the new mounting bolts to specification.
14. Install the axle shafts as described in Section 9.
[The original article is posted at: FORDBOOK.ru]