Defroster Tube

[m37jarhead]

Yoda:
The defroster duct does not interfere with the window locks. The top of the duct just barely protrudes above the bottom of the window; not enough to interfere with working the locks. If you've not seen one, the ducts are kinda' clunky looking.
The duct runs the whole length (side to side) of the front windows. Not an engineering marvel by any means. Can we say "overkill" here? But, with the squirrel cage motor at full blast, it will blow your hat off. In the winter, 35 degrees here in Arizona, I frequently rolled down the driver's window to get some relief from the fender mounted hot water heater because it put out a zillion btu's. My fault for not being able to close the duct from the heater to the cab. (SNAFU?) It's toasty !! I'll "try" to post some pic's. "Try" being the key word here.

[m37jarhead]

Tim:
I sent you pic's of the defroster hole via PM.
Anyone else interested in the pic's send me a PM.
Have pic's of NOS defroster duct too.

[Master Yota]

Thanks for the description Jarhead! I should have looked a little closer at the previous pictures, the window lock handle can be seen in one of them... My heater is mounted under the dash, but the knockout for the defroster is still in place, so i'm thinking perhaps the heater was an afterthought, and just allowed to "fill" the cab with warm air with ability to direct it anywhere.

[Joe]

I've been thinking about adding a heater and defroster to my M-37 but I hate the looks of the standard, big square tube defroster duct and I've been wondering about making one out of round tubing. Has anyone done this? I'm wondering if I can just cut some slots in if for the defroster vents or if I need to put some kind of nozzles on it. Has anyone here made their own ductwork or used ducts out of another vehicle? (I'm considering using some of the old PowerWagon ducts.) If so, how did it work for you? I've also wondered about the possibility of adding AC while I'm at it. (Hey, this IS Florida, after all!) Has anyone else tried to do this?

[cuz]

Joe,

Just run a search of the board for the defroster. That topic came up last year and was discussed and photo'd very thoroughly.

Also look at Cabel's web site where he uses a M151 heater under the dash.

[Joe]

Wes,

I've looked at Cabel's web site and I was seriously thinking of using the same heater and mounting it the same way BUT the last time that he posted he still hasn't hooked up any kind of defroster and it is my main concern. Here's what Cabell said: "Future plans include the design and installation of a defroster setup. At this point, I'm leaning to running a small diameter pipe with holes drilled in it across the top of the dash with the air supplied through a hose running up the face of the dash similar to a setup I've seen in another truck. I'm a bit leery of cutting the holes in the cowl needed for installation of the jeep setup, especially since I have stuffed a few extra gauges into the truck that look like they might interfere with air hose routing. The military setup, that seems pretty hard to find, used a sheet metal duct that went across the top front of the dash that was fed through a hole in the dash (where I located my heater control switch) that looks like it obscured the gauges a bit. "

Besides the fact that the stock defroster looks like crap, I have the same concerns about it blocking the gauges AND I don't want the sharp corners to content with and I don't want to cut holes in my dash if I can avoid it.

I've also searched this site for information about the defrosters but the only thing that I found was for the STOCK defroster. I just searched this site again and didn't didn't any additional information. If you have links to other discussions about defrosters, other than the stock ones, please share them!

[cuz]

The discussion I recall had a piece of round PCV pipe with holes drilled in it making it a nice spray bar. Took up very little space and had a hose at one end feeding it. I tried the search feature here this morning and could not find it. It was a very nice looking installation and had very nice photos.

I recommended Cabel's site for the alternative heater not a defroster.

[m37jarhead]

The defroster duct only slightly interferes with the window latches. See the posted pic's by Cuz. You can see one of the
latches sticking up from behind the duct. When the latch is in full locked position you can easily reach behind the duct
and the window to pull the latch up into the open position.
My previous M37 also had a defroster duct hooked up to a fender mounted hot water heater. That system really put out
a lot of BTU's. Not too important for the weather we have here in southern Arizona but it made short work of
the fog/mist on the inside of the front windows when it rains. Sure beats the fire out of hand wiping with a rag.
For you drivers in the snow, sleet and ice, you'll be very pleased with one of these setups. Toasty is the word.

[Joe]

Wes, your description of the "spraybar" is exactly what I was thinking of. I guess I'll keep searching the archives to try and find out more about it.

Jarhead, I'm in Florida so cold isn't a problem here either but fogging is a big problem with our wet and rainy summers (6-7-8+ months of the year!) I need the defroster worse than I need a heater. In fact, I'd like to had AC just for it's defogging capability. I really don't like the heater sitting out on the fender so I'll probably go with a 151 or other heater mounted inside. Outside mount is fine if you're in a arctic-like, treeless environment but there's too many trees and other vegetation for it to get hung up on around here. I know the outside heater is the correct model and it works well and I'm tempted to stay with it for authenticity but frankly it looks a bit too much like a kludge to me.

[majorhitt]

It looks like the hole will still stick out on the left side a little. Clean it up as much as you can, square up the hole,punch a hole in a piece of sheet metal, cut the patch to just fit inside your cleaned up hole, and butt weld it together. Grind down the weld and the surrounding area for a nice flat surface. This would make a much neater job.

[Master Yota]

Just thought I'd share a few shots of the heater thats under the dash in my M37. I don't know if its a stock unit or not, but it seems to fit well, and might be scavenged from some other Mil.spec. vehicle. It never had the defrost tube though, making it more a "space heater" than anything else...




The motor and squirrel cage are currently out of it. They were unbolted when I got the truck so I'm not sure if the motor is cooked or functional... Testing, repair, and reinstallation is the plan. Unless its a 24 volt motor, then I'll be looking for a 12v replacement...

[m-11]

Disclaimer: I'm not a welder so take it easy om me.

Here is my first attempt at welding. I decided to tack the patches from the back side and yes I did cut out small circles to plug the two holes above the big patch. I clamped a piece of aluminum to the front and laid the cab on its back. I placed the patches in the holes and the aluminum allowed the patches lay flush on the front side. The backside is pretty ugly but it looks like it will hold. After I drill the hole for the duct and the four holes for the mounting screws I'll finish the seam line in the repair.

[majorhitt]

I will not point out how poorly someone else does welding. I weld as best I can, two or three hours of grinding and rewelding it looks pretty good.

[Master Yota]

Anybody can be a great welder, so long as they have access to a grinder! We all started welding with the same results. The only way to get better is practice. Nothing is better to practice on than sheetmetal...

[Carter]

This is the defroster tube on the truck Nick has for sale: