1993 F350 w/International 7.3 IDI Turbo Diesel engine

I have an unattached vacuum line that runs along the upper part of the firewall from the passengers side to the drivers side. It's about long enough to reach the vacuum pump, but I have a feeling it might be intended to be T'd into the 11/32" vacuum hose that goes from the vacuum pump to the brake booster. The PO might have eliminated a T fitting, since it looks as if something funky has been done with that hose.



Could someone possibly do me a big favor and peek under your hood and tell me where this vacuum line is supposed to terminate? Here are two pictures; one showing where it starts (just to the left of the glow plug solenoid), and where it currently ends (sitting on top of the booster).



Thanks very much.

 

Sorry for the bump, but I'm hoping to sell the truck tomorrow to a guy who's complaining that the heater vents don't work right, which is what I think this vacuum line does. Any help would be greatly appreciated. Thanks a lot.

 

Yes, that vacuum hose supplies the vent servo motors. It does not go to the vacuum pump itself, however, rather there should be a plastic vacuum tree somewhere in the engine bay - on my '90 truck it is on the firewall above and behind the air cleaner, but I saw a pic of a '92-'94 IDI once that had it on the driver-side inner fender very close to the PS pump. Actually this is where the hose from the vacuum pump should got to as well, then you have another large hose running from the vacuum tree to the booster. And somewhere under the hood there should also be a tuna-can-like thing with a 3-wire harness plugged into it, that is a low-vacuum warning switch (trips the red "brakes" light on the dash to tell you you just lost your power brakes, as if you wouldn't notice if when you go to stop) and it also gets a vacuum hose that starts from the same vacuum tree.

 

Thanks for the reply LCam.

Definitely no sign of a "tree" anywhere, and this truck is pretty damn original. At any rate, I just t'ed the line into the "main" vacuum hose from the pump to the booster, and all the heater controls work perfectly now.

If that's not the "perfect" fix, I'll let the next proud owner deal with it.

Wish I could keep the truck, but I need the $$$ more right now.

Thanks for your help.

BTW, I found a picture with Google Images that might show what you were referring to. Looks like it has "my" vacuum line going to it, but there's no such thing on my truck. It's the thing right near the hood hinge spring.

 

That silver box next to the hood hinge is the cruise control, and the line hooked up to it is not a line at all, but a cable.

The vacuum tree I saw in that pic I mentioned was between the PS pump and the washer fluid tank, not sure if it actually belongs there or not tho. In any case your fix is perfectly fine, as that is essentially what a vacuum tree does, splits the vacuum from the pump to the other stuff that needs it (in your case just the HVAC and the booster). The low-vacuum warning switch rarely works to begin with even when it's hooked up, so no loss of functionality there with no line to it.

 

This post is exactly about my problem...vacumn lines, climate control vent switch not working. If could view the pics it would be a great help. Anyone know why I can't view these pics. Could it be the age of this particular post?
Thanks

 

One of the big problems with free image hosts is that they often delete pictures.

 

5+ year old posts. you would be better starting a new thread either here or down in the pre powerstroke forum.