Like all Ford F250/Excursion owners I am consistently disappointed with Ford's ESOF locking hub system. I keep my hubs meticulously serviced and have also checked/serviced the vac system, including putting the hubs themselves under vacuum, they function perfectly when checked. However with over 220,000 on my Excursion I invariably find myself leaving the hubs in their locked position in extended periods of snowfall here in Michigan. I ran across these Dorman replacements and decided to give them a try.


Here's the part, Dorman 917-502 from ebay store logicautoparts $23.70:


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Note that here is the part the way it comes from the box. You will have to remove the spring from the OEM Actuator and put it into the new part:


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Once the hub is off the truck, remove the flat internal lock ring with a small flat screwdriver:


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Remove the axle gear, internal spring and internal locking gear:


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Remove the outer locking gear:


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Remove the OEM Hub Actuator:


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Here is the OEM and Dorman part side by side, note that the OEM part has an internal spring that needs to be removed:


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Remove the internal spring from the OEM Actuator by pushing the two halves together. You will notice an audible click when you push the halves together. On one of those clicks the two halves will come apart exposing the spring:


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Separate the halves of the Dorman part. It is NOT MADE LIKE THE OEM part. Hopefully that's what makes it better. In order to separate the halves, twist the two halves in opposite directions about 1/4 of a turn until the tabs line up and they separate. Insert the OEM spring:


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Push the halves together and twist in opposite directions until it locks together:


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I couldn't resist putting a little lithium grease on the thing:


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Ford Truck Picture by kraylake | 2345353 | Ford-Trucks


Re-assemble the hub and put it back on the truck and good luck, I'll try to give an update later this winter on how it works.

 

UPDATE: this upgrade did not fix the problem. I still have one hub that will either not lock in or only partially locks in. When I turn the selector switch to 4wd and move forward there is a audible (and you can feel it) clunk and the hubs lock in however as you move forward and push the accelerator, let off and push it again you can hear and feel that clunk in one of the hubs. It is not locking in. I've resigned myself to the idea that I will simply have to manually locks the hubs in to use 4wd.

I need to go back and do a more through vac check on the system before I completely give up on the system.

 

i have meticulously researched this area when i worked at ford years ago as a quick service tech. i ordered my 2001 f-250 6.8l with manual x-case,but wanted to have a auto locking hubs.
the gem module sends a full vacuum from the vac. solenoid to lock the hubs, and a partial vacuum to unlock the hubs.
if your excursion is diesel the electronic vacuum pump is critical to this operation and the vacuum reservoir,. as there are check valves inside the reservoir.
there are three wires to the vacuum solenoid, one is hot 12v, and the other two is controlled by gem via ground signal, but this is where it gets complicated to unlock signal.
anyways do a vacuum leak check at the "spindle housing" nipple while spinning the wheel....as you know them wheel bearings are known to go bad, i carry one as a spare in the cab. i alrady replaced the driver side bearing.
i will be doing a "how to" manually lock/unlock the auto hubs with two momentary switches, so you don't have to rely on a module to do it.
ok , enuff with my rant....hope you get it fixed

 

This is not how my X locked and unlocked when I tested it used pulses of vac to do what I asked it could that be the truck trying to tell me something is going bad?

 

Thanks for the info, looking forward to your "how-to".

 

not neccessarly, but having two momentary switches you can control the vacuum....you can pulsate it if you want,but once you hit a small bump on a road it will/or should unlock. wether you pulsate it or not, but i do press the unlock switch 3 or 4 times while rolling.
but if i remember right, the gem does add full vacuum to the hubs in long pulses as long as is in 4x4 mode in case it slowly looses vacuum for somereason.....im not sure as ive done this well over a decade ago.
but on mine once i add full vacuum to the hubs, it stays locked...but it doesn't hurt to add more vacuum once in a while..while on 4x4.
i remember the only complicated part was the unlock part of the switch, because it needs a diode as the two switch circuits are connected together.
as of now , i don't even know how i rigged it up. i just been lazy to look under the dash and di-sect the harness