Defrost ducts questions

Does the M715 supposed to have air ducts between the cowl dash and the winsdshield frame ?? I remember that i have two big acces in my weatherstip but i can't remember if i have something on the frame itself or in the cowl dash.

Because right now i have a lot of heat in my truck ... but the windshield still freezing because no hot air comming from the dash ... i think mine is completly sealed or those vents are not opened ...

If someone can post some good pictures of the cowl dash without frame and the base of the frame itself. Rignt now in canada i'm receiving some freezing rain and got about 1" thick of ice on the truck ... so a defrost could be very handy by those days.

Thanks a lot !!!

There should be two slots in the cowl on the body, then two slots in the weather strip, then two slots in the windshield frame that allows the air to flow out of the two vents to the glass. When the shield is up, then the air should be able to flow through all the layers to the glass.

There are two defroster plenums that mount under the dash to two small studs that are welded to the bottom of the cowl.

Check to see if the 'floor/defroster' lever is moving, kinda sounds like it's not.

Didn't think about that.....

I also have found the floor/defrost door can come loose from the shaft and stay stuck in one position in some heater systems.

The defrost, when hooked up and working good, isnt the most effective in temps below 0...by -20 you have to keep a scraper in the cab for the inside of the windshield...

Perhaps adding a booster fan would help? They make them for VW beetles-mount under the rear seat in the supply line--Bugs were notorious for no air to windshield. Mounted right out of the air box it should really provide some air.

Thanks but i'm not gaving a fsj heater , mine is a bus unit with 2 speed fan on it ... and i add a recirculation fan under the dash ... even in -20 running under 30mph a can heat the entire cab and melt every ici on the floor ... but the windshild icing inside. I have with a flashlight to look at those opening but nothing seems to be opened . Will give another try this afternoon since your all confirm those openings.

And also for those underdash plenums ... can it still be possible to find somes ?? With an 8" fan directly on those plenums ... should be having enough flow !!

i installed a surplus 12/24v nos heater unit, without the defrost ducts and after a few licks with my squeegy it will keep up with the moisture just fine

Vintage Power Wagons still may have some of the defroster ducts. They put them up for sale on Ebay once and a while.

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Originally Posted by 503m715

Vintage Power Wagons still may have some of the defroster ducts. They put them up for sale on Ebay once and a while.

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Holy Smokes!!!! They have them listed in the little flyer I have. $40.00/EA :eek:

I think I bought my first set for 12$. They put them for sale on ebay and lately they usually sell for 30-40$ a set.

Yeah, they're spendy.... I sniped a pair off eBay for $30 or $40 a year ago. They're needed though. FSJ ones won't fit the angles at work under there on the M715.

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Originally Posted by Jester

Holy Smokes!!!! They have them listed in the little flyer I have. $40.00/EA :eek:

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It's not cheap :eek:..... will find another solution less expensive !! :D

I'd like to get my hands on a set from a FSJ and compare them with the M715 ones I have. If it's just the angle of them as I've heard, perhaps there could be an easy modification. Like, cut a pie-shape out of the FSJ one, fold it closed and glue it. Something like that. :dunno:

Anyone got a set from a FSJ kicking around?

I remember reading here on the Zone where the FSJ ducts are different and won't work. I also remember someone using a wet-vac floor nozzle like one of these from Amazon.

http://www.amazon.com/s/ref=nb_ss_hi...zzle&x=14&y=22

I have both trucks here, a J10 and M715 - I'll try to get some more info and post it later.

I have the same memories as Amphi....well on this topic anyway!

Calpyro mentioned this on the temp site...it is the whole post:

I used a couple of plastic wet-dry vacuum nozzle modified with a belt sander. I attached them with a couple of machine screws


Even better...from osut362:

i'm ready for the defroster ducts and i'm impatient...i went to wally-world and bought two shop vac 10 inch combo nozzles ( le cheapo). 5.99 each, cut 2 inches off one side to off-set the inlet (was the outlet for vac. but inlet for duct) & cut about 1/2 inch off the other side to square it up. i took the two pieces, (1/2 inch & 2 inch) and welded them back on opposite sides. right on left, left on right. this left it the same length but off set the inlet by 2 inches. trimmed a little hear and there, it fits nice, snaps down on the flange on the bottom of the windshield. used a fender washer on the oem studs and a nut to retain it. looks like to me it will work. don't ask about pictures, it's installed already.

I have a set of the FSJ defroster ducts, no way will they work. I couldn't even come up witha good way to cut glue them back together with the almost 40 year old plastic. I almost went with the vacume nozzles modified. I ended up biting the bullet and paying for a set of those overprices stock ones. I hate it when you get raked over the coals by a company because they have the only one. I know those things couldn't have cost but a couple bucks to produce.

Maybe you have the skills to buy a set and make copies and still be under their price by a fair margin?

I dont...wish I did...

Looked at the J truck and Mike's (503m715) truck. Mike's truck has the stock defroster ducts installed but no heater. Dibbs on these Mike if you are not going to use them!!

The M truck hose connection is 90 degrees facing straight forward. This is to clear the left side of the three-lever switch on the driver's side and to clear the left side of the glove box on the passenger side. Looks like about an inch of interference, if they were to come straight down like the J truck.

The mounting hole pattern is about 10" center to center on both the J truck and the M truck.

Maybe one could install a 12", or larger, floor nozzle and simply offset it to one side for clearance. I doubt if a real good seal is necessary to blow enough air for defrosters.

Does anyone have a picture of those M715 ducts ??

I've seen them before and they really are simple. If anyone has just one they wouldn't mind lending for a bit, I could make a few sets and then return the original.

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Originally Posted by randyscycle

I've seen them before and they really are simple. If anyone has just one they wouldn't mind lending for a bit, I could make a few sets and then return the original.

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I would sign up for a set

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Originally Posted by Jester

I would sign up for a set

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It can be very interesting !!!

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Originally Posted by Kamikaze12volts

Does anyone have a picture of those M715 ducts ??

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At your service, Monsieur!

http://i408.photobucket.com/albums/p...erduct002a.jpg

http://i408.photobucket.com/albums/p...erduct009a.jpg

http://i408.photobucket.com/albums/p...erduct008a.jpg

http://i408.photobucket.com/albums/p...erduct003z.jpg

http://i408.photobucket.com/albums/p...erduct006a.jpg

Randy,

Just ran mine through the dish washer last night. If you need them, give me a shout.

John

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Originally Posted by Binford

At your service, Monsieur!

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Are these NOS for the M715? Where did you get them?

They are way different form the ones in Mike's truck. I assumed his are stock but after seeing yours, his maybe hand made because they are metal and boxy looking.
Yours look just similar to the ones in my FSJ – J10.

Supposedly NOS from VPW via eBay. Still wrapped in factory paper inside that box. Part number is visible in one of the pics.

I have seen some listed on e-bay that were metal as well. Maybe a production date thing? I was planning on making a set out of metal. Just need some dimensions so I am not hanging under the dash trying to measure the outlets!

Snuffy, I may take you up on that offer. I'll PM you a bit later.

Randy

I'll try to remove one today and post pictures with dimensions.

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Originally Posted by amphi

Randy

I'll try to remove one today and post pictures with dimensions.

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Thank you so much! I would greatly appreciate that.

Never seen metal ones....have seen both black and yellowed white plastic ones.

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Originally Posted by randyscycle

I have seen some listed on e-bay that were metal as well. Maybe a production date thing? I was planning on making a set out of metal. Just need some dimensions so I am not hanging under the dash trying to measure the outlets!

Snuffy, I may take you up on that offer. I'll PM you a bit later.

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The ones I saw on Flea-bay were metal too.

Count me in for a set of the Randyscycle's specials :D Would rather give a zoner the money.

This is obviously not factory.

Passenger side removed -- complete with two pencils and some debris. Haven't looked closely at the drivers side yet, but I will and post info if needed..

It is made of thin aluminum sheeting and 2" OD galvanized downspout.

Looks simple to make with a hammer, some tin snips, a two by four, pop rivets, and maybe a hole saw.

It measures:

2-1/4" Tall – no more or it won't fit above the glove box lip.
1-1/4" Deep – front to back.
9-1/2" Wide – side to side.
10-3/8" OC mounting holes
1" Mounting tabs
1-3/4" long inlet pipe.
2" OD pipe

Notice the outboard mounting hole is slotted allowing it to be rotated into place above the glove box lip.

It could use some sort of seal on the open side where it comes up against the dash and at the inlet. Other than that I'm sure it will pass as much air as a stock one.

http://img149.imageshack.us/img149/4...removedsw2.jpg

http://img230.imageshack.us/img230/4839/backcu4.jpg

http://img149.imageshack.us/img149/9527/frontkb9.jpg

They are very different !! But for the metal ones ... the 2" pipe pointing the front of the truck ?? The plastic ones were pointing downward ... for the metal ones , you must at least need a 90 degree elbow ... but do you have enought place for that ?? Are they factory using flexibles from those vents to the heater ??

The metal ones I saw looked very much like the plastic ones shown in an earlier post.

The one that Amphi posted is the idea I had, but a little more of the angle downward like the stock one. I also was considering welding them rather than riveting.

I will get to work on a prototype off those measurements, and see what I come up with, how long it will take to make, and what the cost of materials will run. I'll keep everyone posted as soon as I come up with something.

As posted earlier in this thread, I used two wet-dry vac nozzles from Home Depot. As I recall, they were around two bucks each. They fit the opening in the dash almost perfect and had the perfect bend to accommodate the flexible ducting. Two machine screws and nuts to attach it.
For the ducting, I used some VW heater duct from NAPA Auto parts. Wet dry vac hose would work as well, but it cost a few bucks more.
I finished the whole project in just about an hour including getting the stuff.
This modification for the defroster was just about the easiest modification that can be done for less than $10

i"ll take a look at my local home depot .... don't know if they have the same stuffs up here but with the dimension i may find something .... will let you know by this weekend if i found anything.