Front axle seal - Diesel Forum -
'99 & up 7.3L Power Stroke Engine and Drivetrain Discussion of the '99 & up 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.

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post #1 of 8 (permalink) Old 03-09-2011, 07:01 PM Thread Starter
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Front axle seal

2002 F250, It appears that a rubber lip has broken off the outside of the large front axle seals, both sides. Ring flopping around. I checked my sons truck and his look the same. Is this commom? Does this affect the seal effectiveness? I see where this seal is about $40 and not to easy to get to. Thanks, T
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post #2 of 8 (permalink) Old 03-09-2011, 07:26 PM
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Those are the dust seals and it appears to be a common issue on these trucks. While I don't have to deal with it on my 2WD, I would be uncomfortable leaving them that way if I had a 4WD. That said, I've read a lot of 4WD owners say they don't believe it necessary to fix them. Here's a write-up on the hub maintenance that includes replacing the dust seals:

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post #3 of 8 (permalink) Old 03-09-2011, 09:49 PM
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Just cut mine off. They don't seal any lube, just keep dust/dirt out of axle tube. Old trucks never had those seals and still lasted for many years. When I rebuilt my front axle I did put new ones on and they will be cut off as soon as they come apart again.

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post #4 of 8 (permalink) Old 03-09-2011, 10:59 PM
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I don't think there is a SuperDuty out there that actually has these seals intact (not for very long, at least). Mine looked just like you described. They are just dust seals and the actual fluid seals are in the differential where the axle tubes meet the housing. When I pulled my axles out to put in a locking differential, the inside of the tubes was pretty clean, so you probably don't have much to worry about. Same thing will happen to the replacement seals, so I would save the money.

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post #5 of 8 (permalink) Old 03-10-2011, 01:20 AM
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I'm pretty sure he's talking about the seals outboard of the u-joints, guys, as he said $40 each. The little rubber dust seals are maybe $10 each, and as you say aren't critical. But the big seal in the knuckle can leak vacuum and cause the auto locking hubs not to work, as well as potentially pull water/dirt into the bearing area when the vacuum is applied to try to lock the hubs.

The early trucks had rubber covers on the knuckle seals, which is what starts flopping around, but the later trucks ('04s for sure) used a metal shield inboard of the seal. Trouble is, the shield sometimes gets hooked behind the knuckle bore, making it very difficult to pull the axle shaft out.

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post #6 of 8 (permalink) Old 03-10-2011, 09:38 AM Thread Starter
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This looks like a rubber ring that broke away from the large seal. How would this happen to both trucks. It must be a design flaw. Should I pull everything apart and replace? I bet it will happen again. Thanks, T
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post #7 of 8 (permalink) Old 03-10-2011, 09:53 AM
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If it just the dust seal common issue I would not bother with it.
Heres a good picture of the two

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post #8 of 8 (permalink) Old 03-10-2011, 04:27 PM Thread Starter
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After extensive research on the net it appears to be the dust seal that separates all the time. I called a shop and was told that if 4 wheel drive is used they change into an O ring in no time. Most say it is nothing to worry about. One guy calls this the Hula hoops for super duties axles. Seems strange to me but I guess I'll live with it, I don't off road anyway. T
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  Diesel Forum - > 1999-2007 Ford Super Duties > '99 & up 7.3L Power Stroke Engine and Drivetrain

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