vacuum pump!!!!?????
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New User
Joined: Jul 2005
Posts: 21
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vacuum pump!!!!?????
just replaced vacuum pump on 97 f-250 because it had a hard pedal and could not get the a/c to blow out of anyhting except the defrost. does anyone know how many inches of vacuum the pump should be pulling? because i still have the same problems with the new pump. by the way i have no holes or leaks in any of the vacuum lines.
Hotshot
Joined: Aug 2006
Posts: 10,764
Likes: 39
Sounds like you have two separate problems....The hard pedal could be the booster & the defrost prob could be something from the glove compartment falling on the controls to the heater
Did you test the old vac pump first?....
Or possibly a bad new pump,,Where did you buy it?....
Did you test the old vac pump first?....
Or possibly a bad new pump,,Where did you buy it?....
Post Fiend
Joined: Oct 2003
Posts: 5,903
Likes: 1
From: MICHIGAN
If the booster has a leak you'll get the same symptoms as a bad vacuum pump especially if the leak is big. Remove the check valve from the booster and pull a vacuum on it or pressurize it and spray soapy water on it looking for bubbles.
New User
Joined: Jan 2004
Posts: 24
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Hello all, I don't want to try to hijack this thread but in doing a search for my own similar issue I am looking for the same answer to 1poorboy69's question. My 94 f-250 is doing the exact same thing. When I run it only 15 min. in the mornings drive too work I have rock hard pedal, no brakes and the air will only blow out the defroster. If the drive is any longer you will feel the air move to the vents or floor whichever is selected and instantly the pedal is nice and soft and normal. Upon a stop apply the brakes a few times they get harder and the defroster turns back on, accelerate away, the vent comes back along with the brakes returning to normal. I am looking for help on where to start. Thank you all Love this sight
Post Fiend
Joined: Oct 2003
Posts: 5,903
Likes: 1
From: MICHIGAN
Originally Posted by keck.sc
Hello all, I don't want to try to hijack this thread but in doing a search for my own similar issue I am looking for the same answer to 1poorboy69's question. My 94 f-250 is doing the exact same thing. When I run it only 15 min. in the mornings drive too work I have rock hard pedal, no brakes and the air will only blow out the defroster. If the drive is any longer you will feel the air move to the vents or floor whichever is selected and instantly the pedal is nice and soft and normal. Upon a stop apply the brakes a few times they get harder and the defroster turns back on, accelerate away, the vent comes back along with the brakes returning to normal. I am looking for help on where to start. Thank you all Love this sight
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Post Fiend
Joined: Mar 2007
Posts: 9,010
Likes: 5
From: Johnson City, TN.
I agree ig does sound like the pump is going south on you. Mine did it but it died all of a sudden. Try tj's suggestions and check the lines. You may just have a leak. Too bad the vacuum doesn't go to the motor like a gasser then you could use starter fluid. Oh well.
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Joined: Jul 2001
Posts: 4,137
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From: Marble Falls, Texas
There is a vac line by the passenger side fender that always gets broken. That should be where you find your problem with the only blowing out the def. That could also be a big enough leak to affect the brakes.