M35A2 cabin heater

[jimm1009]

I am missing the flange that is mounted on the rear of the heater box and the soft duct leading to the firewall
and it was missing when I purchased my truck.
This time of year it is handy to have it fully functional and so I am wondering if anyone has seen these particular parts for
sale anywhere or has fabricated them or used acceptable alternates.
Does anyone know what the diameter of that duct is?

A side question that I have; I wonder why this heater was not installed inside on the firewall horizontally. It seems that with
very little alteration that it would fit and then the ducting could be more efficient.

jimm1009 (Jim)

 

[US6x4]

Is it this flange here with the large circular opening or the part that attaches here and necks down? If so I have both pieces that I am not using.

 

[jimm1009]

Yes. Mine is removable and someone took it off. It looks like yours is integral to the box.
What I am missing is the flange that the large duct attaches to feed to the firewall fitting which is also
a flange with about a 1 inch lip on it. I assume that my heater box had the same flange on the box but
since it is missing, I'm not sure.
jimm1009

 

[US6x4]

That back panel is removable on mine as well and it's currently removed from mine. I'll take a picture when I get home tonight.

 

[US6x4]

I have these 2 pieces that are brand new - remo6from my NOS M35 winterization kit. They're off of the heater box that mounts under the hood. PM me if you're interested in either or both of them.

 

[rustystud]

I am missing the flange that is mounted on the rear of the heater box and the soft duct leading to the firewall
and it was missing when I purchased my truck.
This time of year it is handy to have it fully functional and so I am wondering if anyone has seen these particular parts for
sale anywhere or has fabricated them or used acceptable alternates.
Does anyone know what the diameter of that duct is?

A side question that I have; I wonder why this heater was not installed inside on the firewall horizontally. It seems that with
very little alteration that it would fit and then the ducting could be more efficient.

jimm1009 (Jim)

Here's how I modified mine to fit against the firewall. https://www.steelsoldiers.com/showthread.php?150767-Cab-Heater-Modification

 

[Crazyguyla]

The heater box is located under the glove box in the M35A3. See TM 9-2320-386-24-1-1, page 0237-00 for installation.