ESOF Problem
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Senior User
Joined: Sep 2007
Posts: 335
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From: Richmond, Texas
ESOF Problem
When I position the switch into 4x4 High or 4x4 Low the dash lights do not come on. Also, I have a vacuum leak at both hubs.
I tested the vacuum lines from the ESOF solenoid (or whatever it's called, the box on the fender where the vacuum lines originate) and I don't have any leaks in the lines. I put the Mighty Vac straight to the back of the hubs and I definitely have leaks at both hubs.
So, why am I not getting the light on the dash, and why do I have leaks at the hubs? FWIW, I replaced both wheel hub assemblies in March, and everything worked fine at that time. I'm hoping the yellow o-rings are still good. Is there a chance I lost torque on the four bolts behind the hubs causing a failed seal? Is there a seal on the outside of the hubs that could've failed?
I tested the vacuum lines from the ESOF solenoid (or whatever it's called, the box on the fender where the vacuum lines originate) and I don't have any leaks in the lines. I put the Mighty Vac straight to the back of the hubs and I definitely have leaks at both hubs.
So, why am I not getting the light on the dash, and why do I have leaks at the hubs? FWIW, I replaced both wheel hub assemblies in March, and everything worked fine at that time. I'm hoping the yellow o-rings are still good. Is there a chance I lost torque on the four bolts behind the hubs causing a failed seal? Is there a seal on the outside of the hubs that could've failed?
Logistics Pro
Joined: Aug 2009
Posts: 3,609
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From: Arizona
To the OP, there are big yellow o ring seals in the hubs that leak over time. everything has to come apart to change them. Did you check your fuses?
Hotshot
Joined: Mar 2014
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From: Douglassville, PA
I don't know what I was thinking, you are right, thus ESOF
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Senior User
Joined: Sep 2007
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From: Richmond, Texas
The yellow o-rings were replaced in March. I realize they fail over time, but I figured it would be odd for both of them to have failed within six months of being replaced, which is why I'm wondering if there's something I can check prior to pulling both hub assemblies. I have not checked fuses yet.
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Senior User
Joined: Sep 2007
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From: Richmond, Texas
I just checked 19 and 111. Both looked good. I also put the vac gauge at the solenoid, turned on truck, switched to 4x4, and didn't have vacuum. So, I suppose the solenoid is bad.
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From: Richmond, Texas
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Hotshot
Joined: Jan 2011
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From: Puget Sound
When I first got my truck, I replaced every dash bulb because many were dead. If you had an OBDII tool (link in my signature) you might be able to find out if the 4X4 command is working - I think FORScan will show this.
I, too, want to know why the hub leaks vacuum. My front axles and hubs have all new parts, and the front right developed a vacuum leak. I'm contemplating taking it to the shop, due to lack of time to tinker. But... if I know exactly what to look for, I might take it on.
I, too, want to know why the hub leaks vacuum. My front axles and hubs have all new parts, and the front right developed a vacuum leak. I'm contemplating taking it to the shop, due to lack of time to tinker. But... if I know exactly what to look for, I might take it on.
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Thread Starter
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Senior User
Joined: Sep 2007
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From: Richmond, Texas
Well, I left the office to visit a job site and just for the heck of it I turned the switch to 4x4 High and the light came on. Because of the leak at both hubs, it didn't go into 4wd, but at least the light came on.
I'm using a vacation day this Friday so I'm planning to replace the yellow o-rings and the o-rings on the autolockers.
I really want to know why the 4x4 only works sporadically. I'm now assuming it's an electrical issue. Any pointers on where to start looking?
I'm using a vacation day this Friday so I'm planning to replace the yellow o-rings and the o-rings on the autolockers.
I really want to know why the 4x4 only works sporadically. I'm now assuming it's an electrical issue. Any pointers on where to start looking?
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Stewart
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From: Central Coast of CA
Something about it popping out of 4-wheel and back to 2-wheel and that's why he had to lay on the ground trying to get it to stay locked in when I turned the switch. When we got it to work, the light would stay on.
My memory is fuzzy so forgive the lack of details.
Stewart
My memory is fuzzy so forgive the lack of details.
Stewart
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Joined: Sep 2007
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From: Richmond, Texas
A month later...I finally got around to replacing the yellow o-rings and the o-rings on the autolockers in hopes of fixing my vacuum leak. On the passenger's side, I have a very small leak which I'm blaming on a very rusty nipple (where the vac line attaches to the knuckle). The driver's side is still leaking like it was pre-fix.
I haven't done this yet, but I'm going to swap the PS and DS autolockers to see if the current DS autolocker is the cause of the leak. I'm assuming the yellow o-ring is the seal on the inner side of the system and the autolocker is the seal on the outer side of the system. Is my assumption correct?
For now, I capped all ESOF-related vacuum lines.
I haven't done this yet, but I'm going to swap the PS and DS autolockers to see if the current DS autolocker is the cause of the leak. I'm assuming the yellow o-ring is the seal on the inner side of the system and the autolocker is the seal on the outer side of the system. Is my assumption correct?
For now, I capped all ESOF-related vacuum lines.
Lead Driver
Joined: Dec 2006
Posts: 7,092
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From: San Diego, CA
The OEM auto-locking hubs are not the sturdiest hubs and are not designed to be serviceable (at least according to Ford). If it turns out that one of them is a problem I recommend this before you buy another one:
Welcome to guzzle's 4x4 Autolock Hub Lubrication Maintenance Web Page
I have done this several times and my original auto-locking hubs lasted 280K before I gave up on tracing vacuum leaks and installed the Dynatrac kit.
Welcome to guzzle's 4x4 Autolock Hub Lubrication Maintenance Web Page
I have done this several times and my original auto-locking hubs lasted 280K before I gave up on tracing vacuum leaks and installed the Dynatrac kit.
Laughing Gas
Joined: Mar 2008
Posts: 967
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From: coquitlam,BC
A month later...I finally got around to replacing the yellow o-rings and the o-rings on the autolockers in hopes of fixing my vacuum leak. On the passenger's side, I have a very small leak which I'm blaming on a very rusty nipple (where the vac line attaches to the knuckle). The driver's side is still leaking like it was pre-fix.
I haven't done this yet, but I'm going to swap the PS and DS autolockers to see if the current DS autolocker is the cause of the leak. I'm assuming the yellow o-ring is the seal on the inner side of the system and the autolocker is the seal on the outer side of the system. Is my assumption correct?
For now, I capped all ESOF-related vacuum lines.
I haven't done this yet, but I'm going to swap the PS and DS autolockers to see if the current DS autolocker is the cause of the leak. I'm assuming the yellow o-ring is the seal on the inner side of the system and the autolocker is the seal on the outer side of the system. Is my assumption correct?
For now, I capped all ESOF-related vacuum lines.
You could just put in some manual hubs and be done with it.