inherent issue OR problem with ESOF?
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From: MN
inherent issue OR problem with ESOF?
Yesterday I was towing a dump trailer through a field in 4x4, I stopped, loaded the trailer, started the truck and I was stuck. It came out of 4x4 while stopped.
The truck came out of 4x4 the other day while idling for 10 minutes or so. So when I tried to move I was stuck, then I clunked into 4x4, I assume, when it created enough vacuum. I thought something had broke the way it engaged with the back tires spinning.
ESOF had quit all together a year or so ago, and I replaced the vacuum pump and that fixed it. I also installed those expensive stainless steel covered hoses to the hub.
So is this problem or is this just how the ESOF works?
The truck came out of 4x4 the other day while idling for 10 minutes or so. So when I tried to move I was stuck, then I clunked into 4x4, I assume, when it created enough vacuum. I thought something had broke the way it engaged with the back tires spinning.
ESOF had quit all together a year or so ago, and I replaced the vacuum pump and that fixed it. I also installed those expensive stainless steel covered hoses to the hub.
So is this problem or is this just how the ESOF works?
Lead Driver
Joined: Dec 2006
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From: San Diego, CA
Here's the write-up of the testing I did when I had my problem (post #19):
https://www.ford-trucks.com/forums/6...ml#post5194088
In addition to lines, connections and pump don't rule out the vacuum solenoid as a potential issue too.
I hope this helps.
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From: MN
I got a Mityvac! And determined the following.
1) The pump goes until 17"hg and shuts off.
2) The reservoir holds vacuum.
3) The line to the dash holds vacuum.
4) The line to the hubs, when measured near the solenoid dropped from 15" to 10" in 2-3 minutes. Is that sufficient?
5) The solenoid does not hold any vacuum when I pump on it with the Mityvac. Should it?
6) With the truck running; the solenoid releases 4" when I switch the ESOF to 4x4 and immediately it drops. And will not do it again unless I wait a while.
I replaced the seals and o-rings in the hubs and put on stainless lines at the knuckle. Help please I miss not having ESOF.
1) The pump goes until 17"hg and shuts off.
2) The reservoir holds vacuum.
3) The line to the dash holds vacuum.
4) The line to the hubs, when measured near the solenoid dropped from 15" to 10" in 2-3 minutes. Is that sufficient?
5) The solenoid does not hold any vacuum when I pump on it with the Mityvac. Should it?
6) With the truck running; the solenoid releases 4" when I switch the ESOF to 4x4 and immediately it drops. And will not do it again unless I wait a while.
I replaced the seals and o-rings in the hubs and put on stainless lines at the knuckle. Help please I miss not having ESOF.
Lead Driver
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From: Scio, OR
The thing is, the ESOF hubs should not require continuous vacuum to remain locked. A vacuum pulse locks them, then a smaller vacuum pulse unlocks them. Once they are locked, they should remain locked until you switch them out and the system unlocks them.
This would, to me, point to a defective hub.
This would, to me, point to a defective hub.
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From: MN
Is the 4" hg enough to lock them. I am thinking the solenoid is not releasing enough vacuum. If I connect the Mityvac to the "in" (the one that connects to the vacuum reservoir) of the solenoid and it will not hold a vacuum.
And I think, from created vacuum on the line to the hubs, they locked.
And I think, from created vacuum on the line to the hubs, they locked.
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Lead Driver
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From: Scio, OR
I don't think I've ever found specs on how much vacuum is applied for the lock and unlock cycles. But, the fact that the solenoid won't hold a vacuum would make me suspect that it is leaking or something.
It might be that there is enough vacuum leaking through the solenoid to unlock the hubs. During normal operation, there should be a higher pulse when you switch to 4x4, then no vacuum on the hub side at all. Then a lower pulse when you switch out of 4x4, then again no vacuum on the hub side at all.
If you ever show vacuum on the hub side, except when switching in and out of 4x4, then you probably have a bad solenoid. Note that the unlock pulse might not show up right away. The 4x4 control module can wait up to a few minutes or more after switching out of 4x4 to unlock the hubs.
It might be that there is enough vacuum leaking through the solenoid to unlock the hubs. During normal operation, there should be a higher pulse when you switch to 4x4, then no vacuum on the hub side at all. Then a lower pulse when you switch out of 4x4, then again no vacuum on the hub side at all.
If you ever show vacuum on the hub side, except when switching in and out of 4x4, then you probably have a bad solenoid. Note that the unlock pulse might not show up right away. The 4x4 control module can wait up to a few minutes or more after switching out of 4x4 to unlock the hubs.
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From: MN
I took the bottom diagram off the solenoid and the top filter, cleaned them put a couple drops of air-tool oil on them and the solenoid holds vacuum, still does not let more than 4"hg for a couple seconds but it is enough as the ESOF is working.
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Check out the thread/link below for more info.
https://www.ford-trucks.com/forums/8...ml#post7788534
I changed out my solonoid valve in 10 minutes and all is well (photos included on how I diagnosed my ESOF and changed out the solonoid valve and part numbers).
Good luck,
https://www.ford-trucks.com/forums/8...ml#post7788534
I changed out my solonoid valve in 10 minutes and all is well (photos included on how I diagnosed my ESOF and changed out the solonoid valve and part numbers).
Good luck,
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Joined: Dec 2006
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From: San Diego, CA
Is the 4" hg enough to lock them. I am thinking the solenoid is not releasing enough vacuum. If I connect the Mityvac to the "in" (the one that connects to the vacuum reservoir) of the solenoid and it will not hold a vacuum.
And I think, from created vacuum on the line to the hubs, they locked.
And I think, from created vacuum on the line to the hubs, they locked.
To unlock the hubs it needs to get above 6" of vacuum.
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From: MN
the ESOF did work after I took the bottom diagram off the solenoid and the top filter, cleaned them put a couple drops of air-tool oil on them. Still does not let more than 4"hg for a couple seconds but it is enough.
I call the local Ford dealer and they gave me the part number of 9H465. Is this one on ebay the compatible, it looks different? http://cgi.ebay.com/ebaymotors/FORD-...Q5fAccessories
I call the local Ford dealer and they gave me the part number of 9H465. Is this one on ebay the compatible, it looks different? http://cgi.ebay.com/ebaymotors/FORD-...Q5fAccessories
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