Does anyone know what the coffee can on the driver's side sort of underneath the headlight is for? Mine has a small hole in the side of it that looks almost deliberately made, and there is only one vacuum line running into it with the other port plugged.

Thanks

 

take a picture

 

that's a vaccume reserve can.depends on year, should be 2-3 lines. red and black.

 

This one looks exactly like the one that is on the passenger side except it only has one line going into it. I'm wondering if it for some vacuum accessory that my truck doesn't have since it's capped off on the one side. I pulled it out and capped off the line it was connected to. It was connected to a tee, the other two sides of the tee went to the vacuum tree and the cruise control unit.

The small hole in the side looks like someone drove a nail through the side of the can.

 

This is called a vacuum reservoir or vacuum canister. Its purpose is to keep the vacuum signal to the heater controls (or other items, depending on the year) steady during periods of low vacuum, such as wide open throttle. Yours is very rusty and should be replaced. Because it is part of the vacuum system, it must not be open to the atmosphere anywhere. A check valve is usually found along the path.

 

On my Bronco the one down behind the headlight (underneath the wsw reservoir) is hooked up to the cruise control.

 

That looks more like years of rust finally taking it's toll. The one on that side is usually a back-up/connected to the cruise control, if memory serves. Might be able to find a suitable can to make a new one out of, but it's definitely in need of replacement.

 

thanks for all the input I'll see about gettin a juice can or one at the junkyard to replace it

 

If you get one off a GM car from 70s or 80s they are made of plastic, might hold up better in that locaton.

 

the one on the passenger side is for the ac system. If it's not sealed well you'll probably have issues with where the air from your system comes out.