If you really want to be sure, just pull the axles and the carrier. Yeah, its more work, but isn't THAT bad. Plus it doesn't require any extra tools/knowledge beyond your in/ft torque wrench to make the measurement.
My problem with this approach is "since you are in there" creeps in. I don't think I personally would go that far w/out replacing the bearings. And that does require a press and dial indicator at that point.
That said, having replaced many pinion seals on Dana axled Jeeps over the years, if you have your head about it, use the rotational torque before vs. after (plus a little bit - the new seals are almost always tighter) you won't be on the losing end. If you use a four foot breaker bar or impact wrench to tighten it, or misunderstand about in/lb NOT being the torque on the nut, then yes, you are preparing yourself for an expensive lesson.
Pinion Seal
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bluespider262
- Posts: 160
- Joined: Mon May 25, 2015 11:14 am
- Your car is a: 1979 Spider
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seabeelt
- Patron 2019
- Posts: 1614
- Joined: Tue Feb 19, 2008 4:22 pm
- Your car is a: Fiat Spider - 1971 BS1
- Location: Tiverton, RI
Re: Pinion Seal
To answer Chrisg, Yes everything is fine. No leak, no noise or whine of any kind. Have put about 5000 miles on her since. Lucky, maybe so, but Ill take it. No major work on the car this year as I am rebuilding the garage ( it will take me all summer given my schedule) so I plan on just driving the car at every opportunity as usual. Only maintenance this year was to change the oil and the fuel filler rubber hose that started to leak. Otherwise pump the gas pedal twice and she cranks right up. 
Michael and Deborah Williamson
1971 Spider -Tropie’ - w screaming IDFs
1971 Spider - Vesper -scrapped
1979 Spider - Seraphina - our son's car now sold
1972 Spider - Tortellini- our son's current
1971 Spider -Tropie’ - w screaming IDFs
1971 Spider - Vesper -scrapped
1979 Spider - Seraphina - our son's car now sold
1972 Spider - Tortellini- our son's current
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bluespider262
- Posts: 160
- Joined: Mon May 25, 2015 11:14 am
- Your car is a: 1979 Spider
Re: Pinion Seal
Replaced my pinion seal today. 79 with the later style diff.
Only 1 thread was exposed behind the nut. So much for counting theads.
Had a staked wheel bearing nut on it. Not sure if that is stock or not. Found literally 0 in/lbs rotational torque before i cracked the nut. No preload at all registered on the wrench. Not loose but turned way too easy - no resistance when you start to turn at all.
Replaced the seal and put it back to about 6 in lbs preload this time, which was about another 3/4 turn of where i found it. 6 in lbs isn't a fiat fsm spec but 5-10 pretty typical of "used" bearing preload on a seal replacement on most other axles. I think the old seal leaked only because the whole pinion was moving a bit too much sometimes. Old seal looked brand new and not worn at all when I pulled it too. Po fell ill and didn't drive the car at all after its "restore" in the 90s.
Drained/refilled it last year. it looked okay and not a glittery mess. Only put maybe 5 miles on it since. so probably fine I'm hoping.
Only 1 thread was exposed behind the nut. So much for counting theads.
Had a staked wheel bearing nut on it. Not sure if that is stock or not. Found literally 0 in/lbs rotational torque before i cracked the nut. No preload at all registered on the wrench. Not loose but turned way too easy - no resistance when you start to turn at all.
Replaced the seal and put it back to about 6 in lbs preload this time, which was about another 3/4 turn of where i found it. 6 in lbs isn't a fiat fsm spec but 5-10 pretty typical of "used" bearing preload on a seal replacement on most other axles. I think the old seal leaked only because the whole pinion was moving a bit too much sometimes. Old seal looked brand new and not worn at all when I pulled it too. Po fell ill and didn't drive the car at all after its "restore" in the 90s.
Drained/refilled it last year. it looked okay and not a glittery mess. Only put maybe 5 miles on it since. so probably fine I'm hoping.