'71 XJ6 Series 1 vacuum hose woes

while removing the interior for new carpet, i want to install an electric Vintage Air heater valve and when removing the center dash, found some vacuum hoses not connected. looks as if the radio install guys maybe were a bit hard on the install?
the recirc valve is broken and i am trying to source a replacement. in eliminating the heater control vacuum valve, it looks like i can cap one hose and eliminate the hose going to the heater valve. that leave me with a couple hoses to attach to the recirc valve, does it matter which goes where? i imagine it would.
any help is appreciated. thx!





Jay, if you haven’t bought the Vintage Air valve yet, take a look at the one that Old Air in Fort Worth sells. I have had that on my 71 for 6 years. The beauty of this one is it shuts off both hoses to the heater core when heat isn’t needed and recirculates it through the valve. They are comparable in price and Old Air uses the same dash control

i’ve have the vintage air on the for a year or so waiting to get to. i like the old air valve better. the more heat you can keep out of the car the better. thanks! i’ll probably order one up

I had the same problem on my '72. I found the the red tube that comes on a WD40 can makes a great sleeve to fix broken spigots on these items. Stick the tube into the broken ends and glue with Araldite or JB Weld. Six years past and all still works. NOS stock was non existent when I was looking years ago. FWIW.

[quote=“JAY_COOLE, post:1, topic:431405, full:true”]
while removing the interior for new carpet, i want to install an electric Vintage Air heater valve and when removing the center dash, found some vacuum hoses not connected. looks as if the radio install guys maybe were a bit hard on the install?

More likely one or more component failed, Jay - and PO no longer cared…?

Proper function was depending on vacuum, and it’s more relevant what you actually want the system to do. Originally, the flap actuator was controlled by a flap modulator which varied the flap opening vacuum. A heat control modulator controlled vacuum to the heater valve. Both vacuums modified by the heater sensing unit, which varied the vacuums according to cabin temp - to keep a stable cabin temp…

Ie, both the flap settings and the heater valve opening varied with settings to control temps of the air flow; they were not ‘on/off’ devises - the fans giving extra control.

Needless to say, parts are not readily available - so restoring to original function will likely be a problem. The heater valve flow is of course the main temp control - the flap can basically be left open except a low air temps…?

If vacuum is not to be used; hoses should be plugged - there is a lot of them…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)

i knew saving all my WD40 and carb/brake clean straws over the years would finally pay off! thanks, that’s a good tip. now what do i do with the other 437 straws i have?? lol

well, i’m in Arizona, so no need for much heat. i am installing the vintage air rear AC set-up as well. perhaps i’ll see if i can get the valve to stay on recirc and use the window for fresh air, then i can plug some vacuum lines?

Basically, Jay; the ‘AC’ just provides cold air to the intake - the ‘heating’ system then reheats the air to the desired temp…:slight_smile:

Which means the air, external or internal (recirculation) , must somehow be allowed through the heater core. The AC; compressor, evaporator etc, always runs at max cooling - which at times will be too cool for comfort…:slight_smile:

The flap vacuum modulator (horizontal lever) regulates the flap actuator, flap position - and may do so without the heater sensing unit. Likewise, the heat control modulator controls the water valve - and may also do so without the heat control unit. Which basically is there to automatically maintain cabin temp - and manual control may work OK without it…?

It’s, optimistically, a matter of what you have in working order - and connecting vacuum lines. Vacuum is taken from the manifold/carb spigot through a one-way valve to the vacuum tank - then to the modulators from the second connection on the one-way valve - omitting the heater sensor unit if defective. The basic vacuum feed should of course be checked…

Or use electric/manual substitutes to control the flap and water valve - a ‘one position’ set-up may not be satisfactory…?

Frank
xj6 85 Sov Europe (UK/NZ)