Hissing Air leak noise 2003 Expedition - Ford Forums

Goliath · 10-15-2006, 18:26

I need help. Recently within the past 2 weeks. There is a sound that can only be described as a vacuum leak, hiss, air noise coming from the Driver's side compartment in my 2003 5.4L Eddie Bauer Expedition. The sound goes away when the brake peddle is pressed. I don't know if the brake has an air line or something running through the compartment or what. The sound is VERY annoying, but has not effected the performance of the vehicle.

This sound is present for a few minutes even after the car is turned off. But not before starting the truck from cold. But it starts up as soon as the ignition turns on.

Any help is appreciated

thefonz · 10-15-2006, 20:15

Sounds like the power brake booster or the line going to it.

Goliath · 10-24-2006, 06:40

Is this a job I can do over the weekend myself? I have not been able to locate a CHILTON or HAYES manual for this vehicle. So, I don't know where to start.

thefonz · 10-24-2006, 19:28

Quote:

Originally Posted by Goliath

Is this a job I can do over the weekend myself? I have not been able to locate a CHILTON or HAYES manual for this vehicle. So, I don't know where to start.

I'm just pointing you in a direction to look, doesn't mean I am right. You need to verify if that is it. It is a relatively simple job but I don't know what your abilities are. It sounds like they are very limited, since you don't know where to start. That being the case, you shouldn't attempt without a manual, or at least a buddy to help.

Goliath · 09-03-2007, 08:53

Ok I still have not had time to fix this and have learned to live with it, but it's annoying. I have not taken it to the dealership to get an estimate. I did have a chance to get up under the dash today and determined that the noise is coming from a grey cylinder looking thing that wraps around the brake as it goes through the firewall. Does anyone know what that part is? It has ridges on it like a giant straw. If I push on it, the hissing stops completely.

turboyugo · 09-02-2008, 15:36

Just replaced my brake booster this weekend. I removed the clip on the inside, the four screws on the inside, the two screws holding the master cylinder on, the two screws holding the radiator reservoir on and the two screws holding the gadget above the master cylinder with the hoses. . I had air tools and it took me about an hour. If unskilled, pay to have it done. The part is about $100 and it will cause your check engine light to go on.