Vacuum issue

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Oct 27, 2019 | 10:21 AM

tfunk88

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Fleet Mechanic

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From: West by God Virginyuh

Vacuum issue

Hi, I’m working on a friend’s 2005 F250 6.0, and I’m having some trouble figuring out why his vacuum pump won’t stop running. It was replaced in Sept of last year.

When I put my finger over the pump outlet it shuts off. When I put my finger over the line from the pump to the reservoir it shuts off. When I cover the outlet from the reservoir to the 4x4/AC junction the pump runs and runs and runs. However, when I have everything hooked up there is enough vacuum to switch the vents from floor to dash to defrost. Originally when switching to 4x4 the air would go to defrost but after replacing the 4x4 pulse activator that no longer happens. Air coming out the vents stays coming out the vents when 4x4 high is switched on.

Any ideas why the pump keeps running? I’m leaning towards the reservoir having a tiny leak, but...

Oct 27, 2019 | 10:33 AM

Don Naslund

Laughing Gas

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From: Whittier

The way that you are explaining it, it does sound like it is a hole or crack in the reservoir. You also could have an additional crack in a hose by the 4x4 junction. You can blow into a hose at one end of the tank while spraying the tank with soapy water and look for bubbles.

Oct 27, 2019 | 10:34 AM

tfunk88

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From: West by God Virginyuh

Annnnnnnnd I think I found it...dumb m@&$#%*** managed to disconnect his heater control valve line while changing his oil

So, hopefully that’s it

Oct 27, 2019 | 10:37 AM

tfunk88

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From: West by God Virginyuh

Annnnnnnd that’s not it

Oct 27, 2019 | 11:08 AM

tfunk88

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From: West by God Virginyuh

So, pretty sure the reservoir is shot AND the brand new Dorman pulse solenoid has a leak 😡

Oct 27, 2019 | 02:08 PM

tfunk88

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Fleet Mechanic

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From: West by God Virginyuh

Quote:

Originally Posted by Don Naslund

Thanks! The reservoir definitely needs to be replaced, and once we have a known good pulse solenoid we can figure out if the 4x4 lines have leaks as well. AC lines all checked out as good.