Recently, I started this thread: https://www.ford-trucks.com/forums/1...f-problem.html

I was having an issue with my E.S.O.F. not engaging when my hubs were in auto. After getting some advice from others, I did a little checking on my system.
All my vacuum lines were fine, seals were good, as far as I could tell. And the module on the fender well seemed to be working. I could hear the system clicking as I turned the **** to 4HI.
After a little more digging, I discovered the nipples that the air line connects to on the front axle's were completely clogged up with mud and dirt. Using a 7/16" socket, I removed them, liberally sprayed them with WD-40, and cleaned them out with tooth picks, and q-tips. These nipples are hollow, so clean them out good. I then re-attached them to the axle, and snipped about 1/4" off the vacuum lines to get a nice "new" fit onto the nipples.
Voila, problem solved, I now have a fully functioning E.S.O.F. system.
Thought I would pass this along to others, it ended up being a simple 5 minute fix.

 

Good to hear, but keep an eye on it - the mud in there had to come from somewhere, you have a seal leaking

 

X2! about the seal.

 

I agree. Need a diagram, or need to learn how to replace the seals.

 

How many miles do you have on the truck? I ask because if you are going to replace the seals, chances are you may want to do hub bearings and possibly ball joints. You will have to pull the hub bearings to get to the seals. If you are going to tear into it, you might as well do it all while you are there, cause trust me, you only want to do it once and get it right.


I did mine at the first of the year and do NOT want to do it again anytime soon. Truck drives soo much better.


There are posts that detail all the steps needed to replace all of the front components and the parts/tools needed.

 

I have about 96,xxx miles. And, sadly, now the front end does not completely unlock at times. GAH!!! I am thinking of doing the Warn hubs, but, does that still use the rotary switch? I'm a little confused on that.
If the front end re-build is not to bad, I may attempt that. I have some mechanical knowledge, so not afraid to get my hands dirty.

 

Thanks for the tidbit! My ESOF hasn't worked since I bought the truck. I have to click my hubs over to locked from auto in order to use my dash switch to switch from 2wd to 4wd. It hasn't been a big deal since I usually keep my truck in 4wd in the winter most of the time anyhow and 4wd seems to work fine, just have to lock my hubs. In summer I never use 4wd so I just unlock my hubs come summer...

Maybe once I get some more time I will try and see if mine is the same issue.

 

My truck had 97k on it when I went to replace hub bearings. When I got the wheel and brake calipers off, I wiggled the hub and saw movement in the lower ball joint. I decided to repair and replace all parts associated. Glad I did. These trucks are notorious for worn ball joints and unit hub bearings. Should be good for another 100k! FYI, a STRONG back will be needed as some of the torque specs are 100ft-lbs plus. I did mine in the garage and the wheel wells are not accommodating to a large person needing leverage.


As far as the 4wd hubs, Warn hubs will not lock into the axle when you engage 4wd on the dash. They do NOT work with the ESOF vacuum. You will have to manually lock your hubs.


You can remove and perform maintenance on the OEM hubs. Chances are there is mud, gunk or lack of lube in the hubs to cause it to stick. They can be cleaned, lubed and replaced if there are no broken parts inside.