Vacuum Leak Sources - hub

[pez]

Aside from the yellow o-ring and the o-ring on the auto-locker, are there any other seals to check?

My passenger side won't hold vacuum past the end fitting.



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[NoRalPh]

Yea, sure, the BIG one

The Knuckle Seal all the way in the back of the "Big Hole" next to the U-Joint.

Here's some pictures, forget the Ball Joint stuff, I'd replace the U-Joint if it's old because that seal is pretty expensive and if you need to "go back in" next year for that U-Joint you'll likely destroy it...

Ford Super Duty Ball Joint Replacement Procedure | Superdutypsd.com

&

Ford Super Duty Knuckle Seal Tool - AKA OTC 6695 | Superdutypsd.com

In it they call it an "Axel Seal", and I've never had to use a puller like that so, don't let that intimidate you

[pez]

Yuck... It is what it is. Thank you for the info. It appears to be pretty straight forward.

I don't like to throw parts at an issue unless necessary. Can I be sure the knuckle seal is bad solely based on the fact it won't hold vacuum?


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[NoRalPh]

I'd hate to say absolutely, you're putting a pump on the nipple at the top of the knuckle and then trying to pump it down some and it just won't pull any vacuum at all? (I don't know, I've never done that, just assuming that's how I would test..)

[pez]

Originally Posted by NoRalPh

you're putting a pump on the nipple at the top of the knuckle and then trying to pump it down some and it just won't pull any vacuum at all?

Yes, exactly. I can get the driverside to lock up with the pump.

I wasnt the one who installed the new hub on the passenger side. I guess it's possible the o-ring could be faulty. I'm gonna check that before I get any further into it. I assumed, new hub = new o-ring. I always forget never to assume.