No fix vacuum leak

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Oct 16, 2006 | 11:19 PM

lsack1313

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Joined: May 2005

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No fix vacuum leak

Anyone have a suggestion? My 2001 dually with 7.3 Powerstroke has a vacuum problem that I cannot figure out. The auto hubs won't work and the HVAC is stuck on defrost. I am pretty sure it is a vacuum leak but I have tested all lines. I have changed the hub seals, installed a new vacuum pump and PVH selonoid. After installing the PVH selonoid, the problem went away for a day but came right back. I am out of ideas. Any help would be appreciated.

Oct 17, 2006 | 01:13 AM

Cowboy Brett

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Joined: Apr 2004

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From: Wickenburg, AZ

I'd make sure that the vacuum reservoir is not cracked if you haven't already. The next place to visit after that is under the dash to make sure that the vacuum motors in the climate control are working properly. I think you would probably hear a hissing noise in the cab if your climate control head took a dump, but you might want to make sure all the little plastic lines are attached on the motors and the head. Folks on here have had that problem.

Oct 18, 2006 | 06:13 AM

rusty350250

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Joined: Jul 2004

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wow. i consider my self some what of an experienced person when it comes to this as i have lived it more times than in want to remamber. your 30$ hub seal is the most likely cause( if yu changed it you had to pull the axle shaft). solenoid is the next(you changed allready) i have had aproblem with the pump becoming full of mud and crap(you allready changed) these problems are all with the auto hub stuff. if you want to talk let me know of a way to contact you with pics or phone and i will do it.

Oct 18, 2006 | 09:12 AM

krewat

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Joined: Jul 2002

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From: Long Island USA

If it's stuck on defrost ALL THE TIME, there is a vacuum leak BEFORE the ESOF system.

Remove the vacuum feed to the vacuum resevoir, and plug it - check if it's still stuck in defrost.

If it is, there's a vacuum leak elsewhere (or no vacuum to begin with!). With the 7.3, I think you have an actual vacuum pump. Check if it's working right.