Defroster hoses and re-building heater box

[Trevor B]

Hi Everyone:
1971 non-AC Duster and I'm replacing the dash - now is the time to do everything I can at the firewall. Please forgive if stupid questions as I've never been in this part of the car before.

1. I pulled out the heater box and the cardboard backing for the left side is toast. I see that it can be bought from Detroit Muscle Technologies, as can a rebuild kit with all of the foam that sticks to the various doors.
But, should the left-most door only swing about 30 degrees open vs. closed? It can not pass by the backing as it is too tall.

2. The previous owner must have come up with this hose system at some point - there is a LOT of very old tape widening the 2" tubes and surrounding the 2.5" defroster vents. Are these hoses reproduced/available anywhere? Or... is my version just someone's interesting work-around? The bottom port on the heater box was left open and the whole thing was wired to an on-off switch!

 

[Dana67Dart]

Dmt also has hose kits. They are paper wound wire. The OEM hose had a smaller end on one of the hoses. The aftermarket are the same size but have a a reducer.

As for doors.

There is one door that forces air to the defrosters and another that blocks air from entering the box all together.

I believe you will find the door you show is the defrost door and it will either block the defrost holes or the output at the floor.



There are a few good rebuild videos available.

If the vent door hinge is frozen or if the hinge is pulled out of the plastic housing I sell a repair kit.

 

[Kendog 170]

@cruiser posted a hose remedy that looks decent.
Bob's Component Resto, Part 37: The Defroster Hoses

 

[CFD244]

I purchased the hose kit from DMT. When installation day came, I found that the long hose in the kit was too short for its application. I was issued a refund.

 

[Qwiglee]

I have been working on my 69 heater box and it has the same door with the big rubber block attached to it. Yes, it only swings a short distance. The door splits the air between floor vents and windshield defrost. The rubber block never allows it to seal one way or the other so I assume the idea is that if you are running the heat for the defrost you will still get a little bit of heat to the floor vents and vice versa.

 

[Mattax]

They are shaped for the connections and also to promote flow.
Here's one way to save the hoses.

Article 'How to fix a Defroster hose'

OK my 64 cuda Defroster hose is in bad shape. Fixed it on the cheap without wrapping tape around it. Car wrap, just need to find flat black. $6.99 and a half hour. OK take the old stuff from the metal spirals, leave where it is ok. Find a tube that fits the inside diameter of the tube...

• halifaxhops
• Apr 16, 2020
• 1 min read
• Reaction score: 6
• Category: Interior & Trim

Another way is to use tape, but it has to be a tape that will tolerate high temperatures. That's what I did. Check McMaster-Carr and Zoro and you'll find some options that are black.

As far as the heater goes there are photos in this thread from when I installed new seals in my '67 non-A/C box.
Rebuilding heater box, replace core?

My understanding is '71 has different size coolant hoses connecting to the core so there may be some differences from the '67 heater box.
Authentic A-body heater hose