Plenum Door Hinge broken
The hinge on the plenum door has come loose or has broken from wherever it's mounted. When vacuum is released at its motor, the door hangs up and fails to close off air to the dash registers. This stops air-flow to the floor/defrost duct. For now I can just block the vacuum to the plenum door motor, so I'll have floor/defrost capability, but I need a fix to the hinge problem. I can't see where/how the hinge is mounted. I can see the motor attachment and it's ok, but the door is very loose. Need some help/ideas to repair the hinge problem, hopefully without having to take the whole dash/plenum system out.....Thanks for any assistance
> having to take the whole dash/plenum system out
On many Fords the hinge is held in place by a push nut over the end of the hinge rod. If you can push/angle it back in its hole, with a pair of 90 degree needle nose plyers you *might* be able to push another push nut back on the rod end. I have never done it on a 81 Ford with A/C, so your mileage might vary. Though I imagine with the 1.5 inches of room, you probably have to remove the housing unless you go in from the glovebox. Sometimes lying in the truck from teh driver's door will give you enough room to get under the dash at the right angle.
Thanks for the reply. Unfortunately I can't see where the hinge mounts, even with a mirror. My hand is too big to fit in the duct off the heater-core side. What you described sounds right and I see what looks like a 'pin' on the outer surface of the duct which is probably where the hinge mounts. I'll figure out something. Thanks again, I appreciate your help...
Dave





