73 9 inch rear end seal replacement

[Tataocb]

My mustang has pretty much sat in the garage ever since I bought it about 3 years ago waiting for a transmission swap. I would run it for 15 min twice a week. One day I noticed a small puddle of rear end oil.

Now, with all the time spent at home I decided I'd give it a shot at replacing the seal. I saw a few videos on YouTube and went for it. It surprised me that the nut was not on there as right as I would have expected. After removing the old seal, I noticed it does not have an oil slinger.

The oil has a caramel color to it ( kind of like coffee mixed with milk), so I am guessing it's pretty old; and therefore this might be the first time the seal is replaced in a while.

So my question is: should I have an oil slinger between the seal and the bearing (and that is what might have contributed to the leak), or did some of our cars not include an oil slinger?

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[Carolina_Mountain_Mustangs]

I pulled out the Ford shop manual and the picture of the rear shows the following. The flange they have numbered 4851. Then a Deflector # 4859 then the seal 4678. I cannot scan the info computer issue. How tight the nut is on the pinion is set by getting the correct rotational load on the bearings. The manual I am looking at states to tighten pinion nut to 180 - 200 ft. lbs.. You check the rotational force required given in the Ford manual states 12 1/2 - 32 1/2 inch Lbs.. If the force is not right you have to change spacers and the Ford manual has a chart listing them. You need to go looking for a scan of the Ford volume 1 Chassis Manual The 1972 I am looking at has the info on 15-10-17 in Fig. 38.

If I could scan I would but not possible right now. Camera is not good enough to photo either.

 

[Bentworker]

Have you thought about unbolting the pinion support and doing the repair on a workbench instead of under the car? With your description of the oil and the lack of a slinger it might be worth doing that. You could press or tap the pinion out and inspect the bearings while you are at it. Also easier to set up preload on a bench. Just make sure to go back with the same pinion support shims.

If the bearings look bad then you know it is time to pull the axles and third member.

 

[Tataocb]

Have you thought about unbolting the pinion support and doing the repair on a workbench instead of under the car? With your description of the oil and the lack of a slinger it might be worth doing that. You could press or tap the pinion out and inspect the bearings while you are at it. Also easier to set up preload on a bench. Just make sure to go back with the same pinion support shims.

If the bearings look bad then you know it is time to pull the axles and third member.

I don’t think my abilities would go as far as pulling anything else out of there. I did pull out the outer bearing and it looks fine, but now I cannot get it to back in...lol. I probably need to add some oil to it and the shaft to help it slide in, since I wiped the one it had on it when I cleaned it. Sorry, but my knowledge of third member components is very limited.

I thought I was just going in to replace the seal and take care of the leak, but noticed that mine did not have the slinger like the ones in all the videos I watched.

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[Stanglover]

If you're not sure about fixing the rear axle yourself, I think you should consider pulling it and taking it to a specialist who knows Ford  axles and have it done properly.

It's a lot of work to get it out, but doable with the right jack and jack stands to support the car. I use 6 ton stands for this as they are taller and have a bigger base footprint. The part that gave me some issues was removing the parking brake cables, but I found a small gear clamp on the fingers worked fine. While you're at it, why not replace the brakes as well, I mean everything is apart, so if needed , why not.

Attached is my thread on this, I thought it might help... or not.

https://www.7173mustangs.com/thread-71-mach-1-rear-axle-removed-today-for-service