2004 vacuum leak

[alawrence]

Have a leak or leaks in the vacuum system. Vacuum pump runs all the time since I changed the fuel filter. What is best way to find and repair leak in vacuum lines?



Thanks

 

[Bill Stockard]

If you are refering to the electric vacuum pump on the passenger side fender near the firewall, it's used to operate the cruise control servo on '03 and some '04 trucks with an automatic tranxmission. Check the vacuum line from the vacuum pump around the top of the firewall over to the cruise control servo near the driver side battery. You may have accidently pulled the vacuum hose loose from the cruise control servo when you changed the fuel filter. If the lines check ok, try your cruise control to see if it works, if not, remove a vacuum line and connect it to a vacuum gauge to see if the electric vacuum pump is still working correctly. It no or little vacuum is present, you will have to replace the vacuum pump since it isn't servicable.



Bill

 

[alawrence]

Thanks Bill.



After checking the pump by pulling the main line off the pump and blocking it the pump stops, so it appears the pump is ok. Disconnected and blocked off the other connections and it looks like I have multiple leaks. One small leak in the line that goes into the cab of the truck, that is located in the middle of the firewall "what does this line feed" and another larger leak in the line the goes out of that connection that must go to the cruise control located under the driver side battery.



If I have multifple leaks, is it logical to think that the vacuum lines themselves may be getting bad? Where can a person get new vacuum lines?



Thanks

 

[rbattelle]

If I have multifple leaks, is it logical to think that the vacuum lines themselves may be getting bad? Where can a person get new vacuum lines?

That seems quite logical. Vacuum tube is available at any of the usual automotive parts stores. Bring in a sample of the lines you need in order to get the correct size.



Very inexpensive.



Ryan

 

[Bill Stockard]

Thanks Bill.

One small leak in the line that goes into the cab of the truck, that is located in the middle of the firewall "what does this line feed"

Thanks

I'll check the routing in my Factory Service Manual (it's out in my shop) in the morning and let you know.



Bill

 

[Bill Stockard]

After checking my Factory Service Manual (FSM) and my truck, I find an error in the FSM. The FSM states the 5. 9L Diesel engines uses an electric vacuum pump which goes directly to the cruise control servo and does not use a vacuum reservoir. After looking at my truck, the vacuum line is connected to a vacuum reservoir. The vacuum line that appears to go in the cab actually goes to the vacuum reservoir located “in the engine compartment under the fresh air cowl grille”. This is where the windshield wiper motor and operating linkage is located. Look into the fresh air cowl grille in front of the windshield in the center of the cab and you can see the black plastic box that is used as the vacuum reservoir.



The vacuum reservoir may be leaking. To test it, disconnect the plastic vacuum line at the rubber tee and check to see if the system builds vacuum without the reservoir in the system. The plastic vacuum reservoir may have age cracked and be leaking.



Bill

 

[alawrence]

vacuum leak

I purchased a vacuum line harness from the local Dodge dealer and when I went to install it I find that you have to get into the air vent area where the vacuum resivour is located. Bill, does you manual show how to remove that fresh air grate in front of the windshield? the other end of the vacuum line goes to another resivour located under the battery on the driver side and then looks like it goes to the cruise control on the front of the driver side of the engine.



So, it looks like I have 2 resivours. One goes to the cruise control and the other goes to the heater control in the cab of the truck. The parts guy at the Dodge dealer told me this.



I do not have a manual for my Dodge, but looks like I should have one. I see that Geno's garage has a Haynes manual for the Dodge truck. Anyone ever used the Haynes manual. Is it pretty compete?

 

[rbattelle]

Here's the service manual diagram for the cowl. Very easy to remove. Remember to pull the washer solution line.



Ryan

 

[Bill Stockard]

I purchased a vacuum line harness from the local Dodge dealer and when I went to install it I find that you have to get into the air vent area where the vacuum resivour is located. Bill, does you manual show how to remove that fresh air grate in front of the windshield? the other end of the vacuum line goes to another resivour located under the battery on the driver side and then looks like it goes to the cruise control on the front of the driver side of the engine.



So, it looks like I have 2 resivours. One goes to the cruise control and the other goes to the heater control in the cab of the truck. The parts guy at the Dodge dealer told me this.



I do not have a manual for my Dodge, but looks like I should have one. I see that Geno's garage has a Haynes manual for the Dodge truck. Anyone ever used the Haynes manual. Is it pretty compete?

Isolate the vacuum reservoir and test the system before disassembling the fresh air grille. If that reservoir isn't leaking, there's no reason to access it. If you find that the vacuum reservoir under the fresh air intake grille is not leaking, isolate the other reservoir, and then the isolate cruise control servo. Isolate them one at the time until you find the leak.



I'll look at my truck this AM for the additional reservoir near the cruise control servo and let you know.



What I've seen of the Hayes Manual, I prefer the Dodge Factory Service Manual. The digital copy is much less expensive than the thick paper book version.



Bill