ESOF
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ESOF
My hubs will not lock in when they are set to auto. I have a 2011 F250 Super duty XLT. I changed out the solenoid, that didn't work, I changed out the auto lock hub switch, that didn't work. I put a vacuum gauge on solenoid, it was at 10hg. I put the vacuum gauge on the left side down at the wheel, there was no vacuum reading. I then put the gauge on the right side, it was reading about 5hg. I figured there must be a leak in the line somewhere between the switch and the hubs, likely on the left side since there was no vacuum reading at all. So I replaced the whole vacuum line from the switch to the hubs with a brand new one from Ford. The only pieces I didn't change was the short rubber line that attaches at the wheel, didn't know they didn't come with the rest of the vacuum line harness. After all that, the hubs still won't lock in with the ESOF. I don't want to be locking my hubs in by hand every time I think I might need them and I don't want to leave them locked in all the time because I travel 30 miles each way to and from work everyday. Now I didn't put the vacuum gauge on after I replaced the lines. Is there anything else I can look at or check?
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Not sure what you are asking me. What is pump known?
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From: Fort Smith, Arkansas
The diesel trucks have a vacuum pump to run the 4X4 system & brakes and other vacuum stuff since a diesel doesn't make good vacuum.
He is asking if you are certain that the vacuum pump is working correctly. Although the first question should be whether it is a gasoline engine or diesel.
Aside from the vacuum lines the ESOF electrical operation must be verified as well to be sure that the transfer case actuator is going into 4X4.
It won't hurt anything to leave the hubs locked in as long as the transfer case is working correctly and going in & out of 4X4 on demand.
He is asking if you are certain that the vacuum pump is working correctly. Although the first question should be whether it is a gasoline engine or diesel.
Aside from the vacuum lines the ESOF electrical operation must be verified as well to be sure that the transfer case actuator is going into 4X4.
It won't hurt anything to leave the hubs locked in as long as the transfer case is working correctly and going in & out of 4X4 on demand.
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From: Odessa, Delaware
If it is a gas truck, there is no vacuum pump running the ESOF. Vacuum comes from the engine.
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Joined: Mar 2011
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From: Ontario , Canada
My hubs will not lock in when they are set to auto. I have a 2011 F250 Super duty XLT. I changed out the solenoid, that didn't work, I changed out the auto lock hub switch, that didn't work. I put a vacuum gauge on solenoid, it was at 10hg. I put the vacuum gauge on the left side down at the wheel, there was no vacuum reading. I then put the gauge on the right side, it was reading about 5hg. I figured there must be a leak in the line somewhere between the switch and the hubs, likely on the left side since there was no vacuum reading at all. So I replaced the whole vacuum line from the switch to the hubs with a brand new one from Ford. The only pieces I didn't change was the short rubber line that attaches at the wheel, didn't know they didn't come with the rest of the vacuum line harness. After all that, the hubs still won't lock in with the ESOF. I don't want to be locking my hubs in by hand every time I think I might need them and I don't want to leave them locked in all the time because I travel 30 miles each way to and from work everyday. Now I didn't put the vacuum gauge on after I replaced the lines. Is there anything else I can look at or check?
Ok first question........When are you trying to measure vacuum at the lines near the wheel? Right after turning the switch on the dash? On my 2008, (I assume newer years work on the same principle)....after turning the dash switch to 4x4 the PVH solenoid applies 10-14 mm of vacuum to the wheels for I think 10 seconds or so, after that it vents to atmosphere. When you turn the selector switch on the dash back to 2x4 the PVH solenoid applies 5-7 mm of vacuum to the wheels for 5-7 seconds, then again vents to atmosphere. So if you're trying to measure vacuum outside of these time frames....you will find none.
Have you tried measuring for vacuum in the hub/wheel assemblies themselves? This is where i'd start for now.
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This, I wouldn't want to rely on a vacuum system to keep my 4x4 working. The worst thing that can happen from keeping your hubs locked is you may get .01 mpg less fuel economy.
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Ok first question........When are you trying to measure vacuum at the lines near the wheel? Right after turning the switch on the dash? On my 2008, (I assume newer years work on the same principle)....after turning the dash switch to 4x4 the PVH solenoid applies 10-14 mm of vacuum to the wheels for I think 10 seconds or so, after that it vents to atmosphere. When you turn the selector switch on the dash back to 2x4 the PVH solenoid applies 5-7 mm of vacuum to the wheels for 5-7 seconds, then again vents to atmosphere. So if you're trying to measure vacuum outside of these time frames....you will find none.
Have you tried measuring for vacuum in the hub/wheel assemblies themselves? This is where i'd start for now.
Have you tried measuring for vacuum in the hub/wheel assemblies themselves? This is where i'd start for now.
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From: Fort Smith, Arkansas
The difference in fuel economy is negligible, not even enough that you would notice.
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From: Ontario , Canada
I measured the vacuum at the vacuum switch where the line that goes to the hub, it reads 20, when i put the gauge on the ends that that plug into the hubs, only getting about a 4 reading. The only other thing I can think of is the reservoir, maybe it isnt holding enough pressure when everything is connected. Ford wants $118 for a new one. A little steep to just change it out and that not be the problem.
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Yeah, one side is plugged in while I am measuring the other. if the wheel assembly is leaking, must be both sides, that's an expensive fix.