71 Dart A/C car heater issues

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mounting screws for the AC vents go through the two holes on the top of the vent assembly from the bottom. If you need more info post and I will get you some pictures and one of the right screw.
 
It is a little normal for it to work slowly as old as it is. If you can lube up the linkage and the spots where door rotates on the case, that will help. Use something that doesn’t smell as it will get drawn into the air box. I don’t believe they repop the actuators, so used might be your only option, and that is a crapshoot. Looks like you may have got it working.
 
mounting screws for the AC vents go through the two holes on the top of the vent assembly from the bottom. If you need more info post and I will get you some pictures and one of the right screw.

is there supposed to be a “tab” or something like that on the dash side? So something can screw into it? Or is it meant to be a bit and bolt?
 
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OK so here's pictures. What appear to be studs hanging down from the dash are actually simple bolts inserted down through holes that I believe are on all the dash frames. They are retained by a nut tightened against the dash frame. If you don't have holes already let me know and I will get you measurements.
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You put the ducts on from the bottom, there is a nut with a captured washer that goes in from the holes on the bottom of the duct set through metal pieces between the ducts. I think that the only reason the "studs" are so long is that it makes it easy to thread this second nut with the ducts in place. You need a deep 7/16th socket to tighten the duct retainer nuts.
 

OK so here's pictures. What appear to be studs hanging down from the dash are actually simple bolts inserted down through holes that I believe are on all the dash frames. They are retained by a nut tightened against the dash frame. If you don't have holes already let me know and I will get you measurements. View attachment 1715517803 View attachment 1715517810 You put the ducts on from the bottom, there is a nut with a captured washer that goes in from the holes on the bottom of the duct set through metal pieces between the ducts. I think that the only reason the "studs" are so long is that it makes it easy to thread this second nut with the ducts in place. You need a deep 7/16th socket to tighten the duct retainer nuts.

awesome, thank you. That’s exactly what I needed.
 
UPDATE:

The heat is/was working great. Got on the freeway this morning and hammered it pretty hard, got the rpm's higher than usual. The heat was working great up to that point. Seemed to be cool after that. Do these vacuum systems not take too much vacuum? Can i rebuild the actuator or soneone point me in the right direction of a new one? Ill pull the glove box out on my way home today and see how its working while im driving.
 
UPDATE:

The heat is/was working great. Got on the freeway this morning and hammered it pretty hard, got the rpm's higher than usual. The heat was working great up to that point. Seemed to be cool after that. Do these vacuum systems not take too much vacuum? Can i rebuild the actuator or soneone point me in the right direction of a new one? Ill pull the glove box out on my way home today and see how its working while im driving.

Low vacuum can be an issue on cars with aftermarket cams. What you are seeing may be normal. Did the heat come back when you let of the gas?

Does your car have the vacuum reservoir under the hood? That is supposed to help with that. Two things are more likely than a bad actuator:

1. The check valve in the reservoir is bad and lets vacuum bleed back to the engine.
2. You have a small vacuum leak somewhere and the reservoir can’t hold a vacuum while the engine experiences low vacuum during high rpm or acceleration. The leak could be in the actuator.

If the actuator is working, that is probably not it. I don’t believe they can be serviced.

If you have a vacuum gauge, tee it in to the small vacuum line that goes through the firewall & watch it when you turn the engine off. That may tell the story.
 
Low vacuum can be an issue on cars with aftermarket cams. What you are seeing may be normal. Did the heat come back when you let of the gas?

Does your car have the vacuum reservoir under the hood? That is supposed to help with that. Two things are more likely than a bad actuator:

1. The check valve in the reservoir is bad and lets vacuum bleed back to the engine.
2. You have a small vacuum leak somewhere and the reservoir can’t hold a vacuum while the engine experiences low vacuum during high rpm or acceleration. The leak could be in the actuator.

If the actuator is working, that is probably not it. I don’t believe they can be serviced.

If you have a vacuum gauge, tee it in to the small vacuum line that goes through the firewall & watch it when you turn the engine off. That may tell the story.

It does have a edelbrock performer cam, but not aggressive at all. That particular trip the heat didnt come back. But the next morning it worked great again. Ill try and T into the vacuum lines and try that.

This tool is good for pumping up vacuum and watching for leaks.
Lisle Vacuum Pump Replacement Components 70160

Ok cool good to know, thanks
 
I added one on my 69 because it came with the factory air I salvaged out of a 71. It isn’t necessary, but is supposed to keep the vacuum up on the system during periods of low engine vacuum.
Do u have a reservoir?
 
Ok I will try this.

Bought a new 180* thermostat... to replace the old 180* thermostat. No change. I’ll try and see if the blend door does anything.

also, when the time comes, how does this ac vent mount? Is there supposed to be clips under the dash for screws to go into? I can’t see how you’d get a nut and wrench on the back side of dash to tighten. Thanks a bunch you all have great info here!View attachment 1715516580

Sorry for hijacking this conversation. On the bottom side of the dash are two studs that hang down. This is what secures the A/C vents to the bottom of the dash.

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