Thanks, I am reading it now.

Steve

 

Good posts. Whether I get it fixed is up in the air, but now I think I know exactly how to diagnose the problem. Rain tomorrow so not before the weekend.

Thanks all,

Steve

 

Okay, here is a question. When the selector on the dash is operated, does the auto/lock selector on the hub turn or is the action for the ESOF internal in the hub when the selector on the hub is in "auto"?

Steve

 

The second of your choices.

The **** IS NOT somehow turned by the vacuum. It stays locked if in "LOCK", and is controlled by vacuum if in "AUTO".

In any case, the position of the **** is where you manually turn it to. It won't move on its own.

Pop

 

Got it. Thanks. That is what I thought, but it wasn't clearly stated in what I read.

Steve

 

It is soooo nice to be able to help YOU, for a change, Steve!

You've helped so many of us over the years with your professional knowledge of RVs, and I speak for many when I say we really appreciate the time you take with us.

Pop

 

It always spins around. I know a fair amount about RVs, but only a little about my truck so I decided to change that.

From our conversation tonight, I know exactly what I am going to do next on my truck. That saves me an incredible amount of time. I never believe in reinventing the wheel.

Thanks again,

Steve

 

I did some more troubleshooting today which ended in not being necessary, but still leaving questions unanswered.

1. First I repeated my last vacuum tests to verify my system was intact and would hold a vacuum, which it does with no problem from the selector all the way down to the hubs.

2. Next I hooked my gauge to the selector outlet for the 4x4. Start the engine and with the dash selector in 2x I have a 5.5 in. Hg vacuum. Not sure why I even have a vacuum in that line in 2x, but I do.

3. Switch to 4H, vacuum stays the same for 45 seconds and then drops to 0 (zero inches Hg). Move selector back to 2x and vacuum pulses to 5.5 in Hg for 45 seconds, then drops to 0.

4. I figure vacuum is too weak to engage 4x4 so with engine off and selector in 2x, I use my manual vacuum pump to draw a 10" Hg vacuum for 45 seconds. To verify the hubs are locked, I jacked up my front wheels and they were locked on the front axles. Definitely not free wheeling.

5. Next I pull a 6.5" Hg vacuum with my manual pump and verify the hubs have released and are free wheeling which they are.

6. Tie system back to selector and verify 5.5" Hg vacuum at each hub. Reconnect hubs, start engine and switch selector to 4x4. Hubs lock switch back to 2x, Hubs unlock Repeat sequence several times. Hubs locking an unlocking consistently. I am verifying all of this by turning tires by hand and the difference between settings is not subtle.

So my system seems to be working. Have I been wrong all of this time (years) and just not given it time to engage? I don't think so and what gives with the vacuum? It should take at least an "8.75" or greater" vacuum to lock the hubs and 5.9" - 7.1" to unlock them and there is no way I have that, nor can I detect any difference between 2x and 4x4 on my vacuum gauge.

At this point I think my ESOF is working, but don't understand why. I shouldn't have enough vacuum to engage the hubs. It seems like it is the pulse and not the strength of the vacuum that is crucial. Who ever said it would be easy?

Steve

 

I would say your system is working. I will check the WSM when I get my Toughbook repaired Tomorrow or Saturday and re-post the specific Hg.

You might try removing the Hub Locks and Lubricating Welcome to guzzle's 4x4 Autolock Hub Lubrication Maintenance Web Page

The Hubs should be engaged and disengaged monthly. You don't need to go 4-wheeling. Just 4x4 High at about 25 mph and back off after a few minutes. That keeps everything moving and lubricated.

Rather than jacking the truck up, turning wheels, etc., just reach under and turn the front drive shaft. Free turning is unlocked.

I have had either ESOF or Manual for the past 35 years on Fords. Personally, I have NEVER had an issue with the ESOF excluding one time a varmint ate a vacuum line.

I just lube them annually and reinstall, 20 minute job per side, max.

25 of those years were in the Artic North East (New England) so I know Snow. Now, southern living, I don't use them at all. But, still maintain them annually. No ones selling Snow Shovels or Ice Salt here either.

Like anything else, maintenance, maintenance, maintenance. I just replaced my Vacuum Lines out of boredom the other day.


EDIT: Working on my backup Laptop.... Duh.

Here is the FSM:

unblock Operation
The 4X4 ESOF system uses timed vacuum sequences to lock and unlock the wheel ends. A high vacuum level is used to engage the hub locks, and a lower vacuum level is used to disengage the hub locks, after which the vacuum is released and the hub lock holds itself in the proper mode. The vacuum signals are supplied to the hub locks by system components, including the 4WD control module, wiring harness, solenoid, vacuum harness and vacuum seals. As the first step in service, eliminate such obvious items as loose wiring connectings, loose vacuum connections, or damaged vacuum lines.

Disengage Time
"Slow" release of the hub locks is not considered abnormal for this system. Anytime vacuum is applied to the hubs, whether for 4X4 or 4X2, the hub locks will initially engage. If 4X4 was requested, the hub locks will remain engaged, but if 4X2 was selected, the internal mechanism will release only after the 4WD control module timers expire and vacuum is vented from the hub. This normally takes 15 seconds, but can take up to two minutes, depending on how the 4X4 mode select switch was operated. After the hub mechanism releases, internal springs must work the hub lock gears to the disengaged position. Road bumps, vehicle speed, acceleration cycles, or momentary reversal of direction can assist this process, varying the length of time the hub locks remain engaged in each situation.

The ESOF system has a feature which allows the driver to override the vacuum operated hubs. When the front hubs are manually turned to the LOCK position, the hubs are locked at all times, overriding the vacuum operated system. If the front hubs are manually turned to the AUTO FREE position, the hubs can only be locked by turning the 4WD mode switch to one of the 4WD positions.
If the front hubs are unable to be unlocked by use of the 4WD mode switch, the hubs may be unlocked by turning the manual locking hub from the AUTO FREE position to the LOCK position and back to AUTO FREE.

PVM should not be more than 11 in/Hg or Less than 2 in/Hg when switching the ESOF Drive Hub on/off

Acceptable vacuum gauge indicate between 5.85 and 7.1 in/Hg after six seconds but not longer than 60 seconds after switching the 4X4 mode switch to 2WD.

 

It seems like my vacuum at 5.5 gauge is on the edge of being low, but given all is working, I don't think I will do anything for now.

I jacked up the wheels looking for nuances, but all seemed tight and together.

Thanks for the input.

Steve