M923 air conditioning a/c install project

[Over]

Here is the start of my install of a Red Dot HMMWV A/C unit into my M923. I couldn't find anything on the boards (not that it's not there) so here I'll chronicle my findings. I found a great deal on 4 units delivered on a pallet.

 

[Over]

Mounting the interior a/c box

Well it's Saturday evening and the sun has gone down. Was 111 degrees earlier which makes it a bit warm in the M923's cab. Time to drag out the lights and get to it. Fitted the A/C in the cab and tried to figure a way to mount it without getting rid of the passenger seat. The passenger seat will go later but it's nice where it is for now. Turns out in the middle and up is a great spot and the passenger seat can still fold up and down. What I did was picked up some 2" angle and 1/4"x1" nuts and bolts at HD. Measured 32" rail to rail right below the window. I have the hard top but a soft top should make no difference. Drilled some 1/4" holes and mounted the angle iron. Sat the unit on it to check for fit. A couple things to note first pull the top brackets off the unit. Then when you prop the unit on the angle you'll see the bottom condensation tubes keep you from pushing it back. I have a mill so a few measured cuts later it slid right on. A grinder will work in a pinch. You'll notice the unit is just clearing the roof. Perfect fit and the seat clears! I centered the unit in the cab but left enough clearance so I can still slide the rear window open or look back there. Now to prop it up there and figure the top brackets. Chunk of 1/4" rod between front window frame and a/c's vent works for now!

 

[timntrucks]

im subscribed to this.. i need to put one in the 923 thanks for posting this up

 

[Over]

Cab unit top brackets

OK the rod is wedging it up there for now. What can I use for the top brackets? Well I have the ones I unbolted from the top of the unit, holes in them. A little band saw work and I made 2 brackets from a piece of the units bracket. Into the vise and a couple of hits with the dead blow hammer I have my custom brackets. The deal for me was getting them so I could attach them to the cab rails. I was going to run strap all the way across like the angle iron but the mounting holes on the a/c unit were to high in the back. You can see one of the 1/4" bolts is banging into the nuts hold the roof on, will shorten it tomorrow. A few hours and 2 beers (I'm a slow drinker) and I'm done mounting the box! My passenger seat folds up and down and you can still fit one or two kids/grand kids under it. Even an adult can sit in front of it if your not on a crappy road(like ours). Next is to figure if I mount the condenser on top of the utility box or in front of the radiator.

 

[Over]

Mounting the condensor, radiator or side box mount

I am trying to figure the condensor mounting. I see the guy I bought the units from now has the correct radiator mounted condensor for the M923(A2). I am leaning to mounting the condensor that came in the HMMWV kit for 2 reasons. It has 2 really nice fans and all the electrics already on it. The M923's fan usually just sits there till I hit 200-220 degrees so I don't see much air being pulled thru the condensor. Plus I don't want to screw with the fan air clutch activator to make it turn before the temps get there. I measured the front and the HMMWV condensor will maybe just fit with the fans attached. I came up with 6" of clearance between the radiator and hood grill work. The main protrusions are the fan motor humps. Then again it looks like a perfect fit on top of the passenger side under the bed tool box. No heat or air blockage to the radiator from the condensor. So if the truck overheats it's not the a/c causing it. And I doubt the motor even notices spinning the compressor around! If any one has done this or has some ideas please chime in. It will be next Saturday when I tackle this. No hurry since the compressor bracket from Kenway won't be here for a couple of weeks.
View attachment INSTR 16-CU-138.pdf

 

[MO MV man]

Definitely got my attention! Thanks for the thread!

 

[FullSpecial]

Subbed, need to follow this closely!

 

[NYC M923A2]

Looks good!

 

[davo727]

Will driver or passenger be in risk of smacking their head on the side of it? You know sometimes you can hit an uneven dip in the road or off road etc that can make people in the truck get thrown around a bit.

 

[M35A2-AZ]

I too have just started my AC install on my M923A1. I got the batteries moved to the side so far.
Look forward to your post.

Do you have someone lined out to charge it and check for leaks? I need to find someone that can help with that.

 

[Artisan]

Nhc 250 a/c brackets

I have the brackets, yes that is plural, that are needed
to install a Red Dot Compressor (SANDEN) to a Cummins
NHC 250 engine. Not too many left...PM ONLY

NOT home made junk either.

 

[patracy]

That red dot unit looks like it'd be the perfect setup for my MK48 cab.

 

[Over]

Will driver or passenger be in risk of smacking their head on the side of it? You know sometimes you can hit an uneven dip in the road or off road etc that can make people in the truck get thrown around a bit.

Oh I'm sure that's possible! My kids (7) grew up knowing that when in the Suburban (Old 83 diesel, 6" lift on 35" tires) on our crappy road you do not let your head get near the side windows! Only took a few bad holes in the road for them to figure it out. Plus in the M923 I thought passengers where hanging on to the front grab rail so they didn't go thru the front window when you put on the brakes!

 

[Over]

Alright!!!! Kenway has shipped my brackets! Ran me $212.90 shipped. Part #16-CU-138 for the NCH250 non turbo motor. They have other brackets available but you will have to call them. Also there is about a 2-3 week lead time as they build them to order. Took apart my condensor last night and will have pics of the mounting on my passenger side tool box on line in a few days. Can feel the air conditioned comfort already! It's 110+ here lately.

 

[AZ Mitch]

Regarding post # 10, I use propane to leak test, pressures’ are similar to R 134. And provide a very respectable temperature split.

 

[M35A2-AZ]

Regarding post # 10, I use propane to leak test, pressures’ are similar to R 134. And provide a very respectable temperature split.

AZ Mitch, Thanks for the reply. After I get my sytsem installed I will need to find someone that can pump it down for me and get it working.

 

[davo727]

Consider buying a vacuum pump and gauges and then you will be all set.

 

[Stretch 379]

What red dot kit and compressor is that if you don't mind me asking. New to these particular trucks and need to have one installed in mine once it gets here. I don't have the time to do it my self and was going to let my mobile mechanic install it. Is there anything I need to advise him of before jumping in head first, will he be able to run to thermoking or where ever they are sold and get what's needed. The truck will be busy so I am trying to keep its down time to a minimum for the installation. And I apologize if I am sounding dumb. This will be the first 923 I've owned. Looking fwd to learning as much as I can about it. Every one generally speaks pretty highly of them for off road haul trucks from the other companies I know who use them. Thanks. Lol and bear with me. Just joined and am still trying to figure all this posting, replying stuff out. Lol. Not the biggest computer guru out there for sure. Lol. Thanks again.

 

[Over]

Harbor Freight has cheap air operated vacuum pumps $20 I think or less, and they pump it down just fine. I had a $400 pump that went south and really didn't want to spend the money to rebuild it. Remember on the air operated ones you need a fairly good compressor/air supply Got my gauges from Checker pretty reasonable. Hated to buy another set as I had a old set but wouldn't work with the new stuff. I heard propane is actuall used in some industrial units. Is there something in the standard propane (smell) that will affect the seals or is it good to go?

 

[AZ Mitch]

I have a vacuum pump, and gages, you’re welcome to use. I’m about 70 miles east of you. My neighbor is an A.C. Contractor, and I’m sure he would jump in and help. He’ a jeep guy, but keeps breaking things on his buggy. I think he needs to go big, like ( A.M. General big.)