Problem with ESOF
Thread Starter
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Junior User
Joined: Oct 2003
Posts: 51
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Problem with ESOF
The ESOF on my 2000 Excursion stopped working. My local mechanic said that I had to replace both hubs because the Auto/Lock **** wouldn't turn due to trapped dirt.
I completely took the hubs apart to clean out this trapped dirt and found that the inside of the hubs was clean all the up to the rubber diaphram that is just behind the Auto/Lock ****.
I then suspected a vacuum leak. I tried to test for a vacuum leak by sealing the hub opening (with the hub removed) with a thin plastic membrane stretched over the opening (like saran wrap). I expected to see the vacuum suck in this membrane but it didn't happen.
I know there is an o-ring further inside the hub assembly which is a pain to get to.
Does anyone know if the inner o-ring is prone to
failure or ever had to replace this?
I also checked the amount of vacuum that the truck was providing in 4x4 mode
by putting my finger on the end of the vacuum line just at the hub. To my surprise, the amount of vacuum was so slight, it would not hold my finger to the hose.
I'm under the impression that when ESOF is turned on then there should be a constant vacuum pull at the hubs.
Is this correct?
I would appreciate any advice as I want to avoid the expensive 'lets replace the hubs and see what happens' experiment.
Sincerely,
Grcutter
I completely took the hubs apart to clean out this trapped dirt and found that the inside of the hubs was clean all the up to the rubber diaphram that is just behind the Auto/Lock ****.
I then suspected a vacuum leak. I tried to test for a vacuum leak by sealing the hub opening (with the hub removed) with a thin plastic membrane stretched over the opening (like saran wrap). I expected to see the vacuum suck in this membrane but it didn't happen.
I know there is an o-ring further inside the hub assembly which is a pain to get to.
Does anyone know if the inner o-ring is prone to
failure or ever had to replace this?
I also checked the amount of vacuum that the truck was providing in 4x4 mode
by putting my finger on the end of the vacuum line just at the hub. To my surprise, the amount of vacuum was so slight, it would not hold my finger to the hose.
I'm under the impression that when ESOF is turned on then there should be a constant vacuum pull at the hubs.
Is this correct?
I would appreciate any advice as I want to avoid the expensive 'lets replace the hubs and see what happens' experiment.
Sincerely,
Grcutter
Post Fiend
Joined: Jan 2002
Posts: 5,859
Likes: 7
From: USA
chk this out
[url]www.4x4tools.com
There is not a constant vacum at the hub /knuckle
fitting its a pulse vacum type system .
it should pump up to 10 in of vacum to move the
hub internally if your not getting at least that much vacum to the hub/knuckle ***.It won't lock in.
you either have a vacum leak or a bad pvh solenoid .
Rich
[url]www.4x4tools.com
There is not a constant vacum at the hub /knuckle
fitting its a pulse vacum type system .
it should pump up to 10 in of vacum to move the
hub internally if your not getting at least that much vacum to the hub/knuckle ***.It won't lock in.
you either have a vacum leak or a bad pvh solenoid .
Rich
Thread Starter
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Junior User
Joined: Oct 2003
Posts: 51
Likes: 0
Thanks for the URL; This looks like a good tool for my local mechanic to own.
Do you know where I can get more information regarding the pulsed vacuum system? i.e. how quickly after switch on the ESOF do the vacuum actuate and for how long?
I was flicking the switch and then rather casually walking around the truck to check the vacuum and so may have completely missed the pulse.
Also, where is the pvh solenoid?
Sincerely,
Grcutter
Do you know where I can get more information regarding the pulsed vacuum system? i.e. how quickly after switch on the ESOF do the vacuum actuate and for how long?
I was flicking the switch and then rather casually walking around the truck to check the vacuum and so may have completely missed the pulse.
Also, where is the pvh solenoid?
Sincerely,
Grcutter
