So the esof on my 99 F250 is really being a pain. I replaced the vacuum solenoid and still nothing happens. When I pulled the old one off it release the pressure in the vacuum lines so I know those are sealed. I also checked the relay's and they both work. What else is there to go wrong?

I just looked and saw my other thread is called "self problems", which explains why nobody looked at it. Stupid autofill on the phone. Mods, could you delete that other thread?

 

I'd clean the hubs if that's never been done:
Welcome to guzzle's 4x4 Autolock Hub Lubrication Maintenance Web Page

He has more info on ESOF leaks here also:
http://www.guzzle7pt3.com/nblube.php

 

Thanks! Hopefully one of these weekends I can clean them.

 

Have you tried twisting the ***** on your hubs manually to see if they will lock in?

 

I would check for vacuum @ the hose to your hubs. On my 06 V10 I found the Poly-Flow tubing that ran from the PVH Valve down the frame near the starter and exhaust manifold had melted together so my heater and A/C vents all worked as they're supposed to but my hubs wouldn't engage. I bent up a new vacuum line using 1/8" stainless tubing. I know it will never melt. Now my ESOF works perfectly.

 

I am having the same issue and have decided to replace the hoses and o rings (thanks for the link to those parts). I want to know what other parts I should order while I have the hubs apart?

 

Yep, the manual lockers work, just not the automatic vacuum system.

 

Well, as of now I don't think I'll be using my esof, and just sticking with using the manual hubs. When I went to Ford they told me it would be like $100 for all the gaskets and O-rings per side. And then I had to ask what a hub would be. $350.
"That's for two right?"
"Nope, that's just one"
"I think I'll just get out in the snow and lock the darn hubs"

So unless anyone knows where I can get a rebuild kit for a lot less than that or a set of working hubs for cheap I think I'll just put the vacuum solenoid up for sale, as I don't want it to just go to waste and it's brand new.