vacuum leak
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Senior User
Joined: Jun 2011
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vacuum leak
Ok I went through the whole esof vacuum leak so I bought warn hubs and capped off all lines. Well I put my truck in four wheel drive and my ac went through my defroster...what gives? If its not one thing its another
Tuned
Joined: Dec 2008
Posts: 373
Likes: 5
From: Evergreen Colorado
When you have air coming out the defrost only your truck is in a default mode of some kind. Meaning you have a vacume leak somewhere
I only know this from research Ive done because my truck does the same thing. I havnt had time to look into mine yet except for checking the vacume pump.
I would suspect that you and I both could have a leak at the hubs.
I only know this from research Ive done because my truck does the same thing. I havnt had time to look into mine yet except for checking the vacume pump.
I would suspect that you and I both could have a leak at the hubs.
Lead Driver
Joined: Sep 2005
Posts: 9,399
Likes: 188
From: Norco,CA
I had a leak under the passenger battery where acid must have driped. It eat a hole in the line. Once I fixed
it there all was well. Just thought I'd let you know where mine was. Good luck,
Chet
it there all was well. Just thought I'd let you know where mine was. Good luck,
Chet
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Hotshot
Joined: Jan 2011
Posts: 18,849
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From: Puget Sound
I had a leak in my ESOF module on the passenger fender (you no longer need this) and in the lines to the hubs (capped doesn't stop a split line from leaking). There are very few things that have vacuum going to them, so it's a very small list of things to check.
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Lead Driver
Joined: Dec 2006
Posts: 7,093
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From: San Diego, CA
If the ESOF Module that Tugly refers to is the vacuum solenoid that provides the vacuum "pulse" to the hubs, then I've had the same problem. If your truck defaults to defrost mode when you into or out of 4wd for several minutes then goes back to the selected ventilation mode, this could very well be your problem or any of your vacuum line in the engine compartment. Those are the symptoms I had. I had already replaced all my vacuum line in the engine compartment and when I replaced my solenoid things worked great again (for about a year). Since you have Warn hubs you woldn't need this solenoid again. You can test this by pulling the vacuum line off of the solenoid, temporarily plugging it (could be with your finger in you have somebody to hellp you) and then turning your ESOF switch to 4hi. If your ventilation does not go to defrost, then you've found your problem and you can permanently cap that line. This will also isolate all of the vacuum line inside the engine compartment.
It's a Van Gogh
Joined: Feb 2010
Posts: 7,813
Likes: 1,335
From: Elk Grove, CA
X2 on Trey's idea to check the vacuum connections in the cab. Remove the glove box and there they are.
When I put in my manual hubs I re-routed the vacuum line under the hood, see the pic below. The HVAC vacuum line comes into the engine bay by the hood hinge, top left in the pic. Then it went over the fan motor and center-right in the pic you will see a white cap where I disconnected it from the rest of the vacuum system. Then I ran the HVAC line straight down the fender directly to the vacuum reservoir. Pull the "T" from the reservoir (capped it in blue, foreground) and insert line from cab. A bit of spit will ease assembly. Just the right length and a handy hole to clip the line to the fender.
All that ESOF vacuum stuff can just sit there in case I want to rebuild the stock hubs someday. The HVAC gets vacuum directly.
When I put in my manual hubs I re-routed the vacuum line under the hood, see the pic below. The HVAC vacuum line comes into the engine bay by the hood hinge, top left in the pic. Then it went over the fan motor and center-right in the pic you will see a white cap where I disconnected it from the rest of the vacuum system. Then I ran the HVAC line straight down the fender directly to the vacuum reservoir. Pull the "T" from the reservoir (capped it in blue, foreground) and insert line from cab. A bit of spit will ease assembly. Just the right length and a handy hole to clip the line to the fender.
All that ESOF vacuum stuff can just sit there in case I want to rebuild the stock hubs someday. The HVAC gets vacuum directly.
Hotshot
Joined: Jan 2011
Posts: 18,849
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From: Puget Sound