Differential pinion seal

[clusterbuster]

One of these days I have to replace the pinion seal on the 57. I ran across this procedure a while ago. I am wondering if it would be okay to remove the pinion nut with an impact gun? I don't want to mess up the bearings if it would affect them. Let me know what you think.

1 Park the vehicle on level ground. Loosen the lug nuts on the rear wheels. Raise the vehicle with a jack and support it with jack stands. Remove the lug nuts and rear wheels.

2
Mark the U-joint cap and the pinion yoke with white-out where the cap is seated. Remove the bolts on the U-straps that hold the universal joint onto the pinion yoke. Remove the straps. Remove the universal joint and the driveshaft from the yoke and lower the driveshaft to the ground. Be careful that the caps on the U-joint do not fall off.


3
Place an inch-pound needle-type torque wrench and socket on the pinion nut. Apply pressure to the torque wrench clockwise and note how many inch-pounds of pressure it takes to move the pinion yoke through a couple of revolutions. Write this value down, as you will need it when you reinstall the nut.

4
Mark the pinion yoke and the shaft with white-out so you can realign the parts when you put it back together. You will be using a new pinion nut.

5
Remove the pinion nut (and washer if it has one) by placing a large pipe wrench on the pinion yoke to hold it stationary and using a breaker bar and socket to turn the pinion nut counterclockwise. Note that it will take a lot of force to remove the nut. It is torqued at around 225 ft.-lbs.

6
Place a drain pan under the rear axle in case any gear oil leaks out when you remove the pinion yoke. Try to pull off the pinion yoke. If you cannot pull it off, use a two-jaw puller to remove it.

7
Pry out the old pinion seal with a seal removal tool or a small pry bar.

8
Wipe the area on the axle housing around the pinion seal with a shop rag. Apply a light coat of oil to the inside rubber part of the new gear oil seal. Apply a light coat of gear oil to the outside of the new pinion seal.

9
Place the new pinion seal against the axle housing and tap it into place using a hammer and seal-installing tool or a large socket that is the same size as the outside diameter of the new seal. Make sure the new seal is completely seated against the axle housing.

10
Line up the pinion yoke with the painted mark and push on the yoke as far as possible. Install the washer (if it had one) and nut. Tighten the nut with the breaker bar and socket to draw the yoke onto the pinion shaft. After the pinion yoke is fully seated on the shaft, use a torque wrench to tighten the pinion nut to 200 ft.-lbs. while holding the yoke with a pipe wrench.

11
Switch over to the inch-pound torque wrench and turn the pinion nut. Note the amount of pressure required to turn the nut. At this point the pressure will be less than what you wrote down. Switch back to the torque wrench and increase the torque by 5 ft.-lbs, to 205 ft.-lbs. After obtaining 205 ft.-lbs. of torque, recheck with the inch-pound torque wrench. Keep switching back and forth, increasing the torque by 5 ft.-lbs. until you obtain the same inch-pound force required to originally turn the pinion nut.

12
Replace the driveshaft and U-joint in the yoke by lining up the marks you painted on the U-joint cap and yoke. Reinstall the u-bolts, washers and nuts. Tighten the nuts.

[rmk57]

It sounds like this procedure doesn't require replacing the crush sleeve.

[John Palmer]

The hardest part of this job is holding the pinion yoke while your loosening and tightening.  It's easy to fabricate a holding tool much like was used in dealerships back in the day.  Long bar with a flat plate welded to it.  It had a large hole in the middle for the socket, and four holes to run bolts through the yoke.  I worked next to the "differential guy" at a Ford Dealership from '65 to '71.  He always used an impact, and could tell the crush load "just by feel".  But, I guess you get good doing a couple of ring and pinion set ups every day.

You also want to make sure there's not a groove worn into the seal surface on the yoke.

[clusterbuster]

Thanks John. I have used an impact gun for taking the pinion nut off cars back in the eighties. Didn't have to hold any thing, just put the juice to it.  I'm a ways from doing the job, so I will wait for some more comments. Thanks again.

[hiball3985]

First a question: Do you have an original 57 third member? The 57 has a large seal that has to be installed from the inside of the pinion bearing retainer. Later ones use a small seal that can be replaced from outside like in the instructions you posted..

[canadian_ranchero]

First a question: Do you have an original 57 third member? The 57 has a large seal that has to be installed from the inside of the pinion bearing retainer. Later ones use a small seal that can be replaced from outside like in the instructions you posted..

when i changed my pinion seal on my 57 diff [the big one]it went on from the outside.i counted the theads sticking out of the nut,used that as a referance.

[hiball3985]

when i changed my pinion seal on my 57 diff [the big one]it went on from the outside.i counted the theads sticking out of the nut,used that as a referance.

I know I'm getting old and the memory isn't what it use to be but I'm almost positive it went on from the inside as a remember pulling the whole pinion retainer to do it, that was two years ago but I'll look again when I get out to the shop, that rear is still out there. I built a new rear from a later model with the small seal and have that in the car now.

Edit: Maybe I couldn't get the old seal out and pulled the retainer to drive it out from the rear? Too many projects and too few brain cells that record for any length of time 

[clusterbuster]

posting a picture of the 9 inch rear that was worked on when changing the seal. Hope the pic is the right size.