I am having some trouble with the heater door opening on my 69 Fury. The doors are moving to route the air between the floor/dash/defrost, but the heater door isn't moving. I started tracking down the lines and don't see any lines from the carb, manifold or booster going to the firewall. I checked the service manual, but that didn't help me or I over looked it.
Does your car have the vauum resevoir on the right inner fender? If so, thats a great place to find and start tracking the lines. The line should be on the engine at the tee where the brake power booster line connects. From there it is probably routed next to the wire harness along the firewall making it harder to see. My gut feeling is that if the doors are moving when the buttons are pressed is that you have vacuum and your problem is in the control head or at the box under the dash. Check the linkage on the side of the box to make sure nothing has come loose or got bent somehow. Check for vacuum at all the actuators(some have two connections,on oposite sides of diaphram).hope this helps. I've got a nice photo showing vacuum soure tap on my New Yorker but i don't have any idea how to post it here.. If you wish, e-mail me and i shall forward it to you
That is where it gets weird. The vacuum ball has two line that run straight back to the firewall. The vacuum connection on the intake manifold that goes to the booster has the smaller line capped off. So there is vacuum coming from somewhere to operate the air direction doors. It is all quite strange.
Top line on ball goes to engine vacuum. Bottom line runs to control head. You need to trace each line by hand to see where they go. I'll bet some one routed the source line to the carb. Fire up the motor and pull the top line off vacuum ball and see if there is vacuum. If so, reconnect it and remove lower line from ball and see if there is vacuum at nipple on ball. Vacuum tank has one way valve in it allowing it to maintain vacuum "charge" in it. Test this by appling vacuum to top nipple while plugging lower one with fingertip or rubber cap. Remove hose from top connection while still plugging lower: no vacuum should be lost. Remove lower plug and a rushing/suction sound should be heard. If the tank fails, bypass it by joining top and bottom hoses together(just remember which one is which) and see if your mode doors work better. Case of ball may be cracked, plastic only lasts so long. Check all the vacuum lines while your in there as they also crack and get brittle with age.
The damper vacuum is taken off the fitting your power brake booster get's connected too. There is a little spur on the fitting. That is the factory source. If your manifold isn't stock, it may have been ommited. It goes from there to the "Ball" or vacuum resevior, then to the heater controls. The hose connecting to the fitting is black and about the size of a piece of #10 wire. (Same size as the fusable link wire from the battery) If the hose is broken, the vacuum leak is so small it's hardly noticed. It's pretty hard to see, usually burried behind the coil. If it is stock, feel around it for the fitting. If no hose, it's probably hanging down behind the engine from the harness area.
It is common for those to dry out and break, or get pinched. It runs from the fitting straight to the fire wall and follows the harness down the right fender to the ball.
If you have no power brakes, and no barb to connect to, you can make one from a hex pipe plug and some JB weld. The thread size is 3/8 NPT
The barb off the manifold is capped, both lines on the ball are routed to the firewall. There no vacuum on eiter line. The shop that did my body work did amazing body work, but the guy they had do some of the mechanical stuff just didn't pay attention. It just has me weirded out that there is some vacuum under the dash, and I have no idea from where!
Scott It can be only gotten from a couple of places. Is the manifold and carb stock? If so, then there is only one place for him to get vacuum. Off the vacuum advance line. In 70' they added the inlet heater that required direct vacuum. Maybe! you don't have enough vacuum going in there. I would see if you can run a line from the reservoir to the capped off barb and see what happens.
Hello again, did a little recon on my car as to the vacuum line routing.You'll need to get your head under the right side of your dash by the right kick panel. You should see three vacuum lines coming through the firewall several inches above where the carpet ends and a few inches left of the right kick panel.Before i go any farther, my car has heater and A/C and vacuum operated water valve(mounted right inner fender). Hopefully your is the same. now for the routing and hookup. Starting at the engine a line comes from the vacuum tap on the intake manifold. this is the same fitting that the power brake booster gets it's vacumm from. the line then runs back to the firewall and over to the right side to the right inner fender, then forward to the vacuum ball and hooks up at the top fitting. The lower line from the ball goes rearward on the right inner fenderand drops down the back of the fender and to the pass-thru in the firewall where you can see it from under the dash. This line then (on the inside /under dash) goes to the left and ends up at the control head. there is a whole vacuum line harness running under the heater assy so don't be suprised when you find about 5 hoses down there. Factory service manual has decent views of this stuff under the dash plus how to route it to all the acuators. Earlier I mentioned that there are three lines coming thru the firewall. One is the line from the ball. the other two are tee-ed together just before they go back out to the engine compartment and they should be different diameters. The thin one goes to the right side of the time delay relay. The thick one goes to the water valve. I think these two lines are paired so that the timer to run the A/C knows how long to run it based on whether or not the operator is requesting heat or A/C. Service manual does not really go into so I'm dead reconning here. I hope this makes some sense to you. After dinner, I went out to the shop and took some photos from under the dash and underhood. If you wish, send me an e-mail and I'll forward them along with some circles and arrows on them pointing out a few things. I know how frustrating these problems get, especially with your head jammed under the dash.