LMTV Air Conditioner

[Third From Texas]

Very similar. And not that far off from the $1550 shipped I paid for the correct cab unit. They have gone up this year and as we get closer to summer..... it's a supply and demand thing. That RedDot unit may be $600 cheaper than current asking price for the military unit but the supply likely outstrips the demand. That's kinda my point - yeah it might cost a *bit* more but for correct fitment it's negligible when you consider the additional labor in moving existing holes in the cab, adapting wiring, etc. And throw in that I would like it to have the stock appearance...... no brainer for me.

Rgr all.

As you said once, we all have variations of time and money. I'm retired on a fixed income, but have plenty of time.

 

[Guruman]

@m-35tom Did you ever get those A/C brackets in? I have my interior gen2 unit thanks to a member here, along with the compressor and the pulley from CAT. I'm not sure what I'm doing for a condenser just yet, but it seems the brackets are still the long pole in the tent here.

 

[m-35tom]

I have 20 compressor mounting kits on the way, also plenty of evaporator units and plenty of condenser units, wiring, hose fittings, etc

LMTV Parts and Hard to Find Replacement Items

LMTV truck parts

www.lmtvtrucks.com

 

[charlesrg]

Just want to add as a reference here. There are two type of idler pulleys and they require belts of different lengths.



Source PS 798, page 19 https://www.psmagazine.army.mil/Portals/74/PDFs/Archive Numbered Issues/PS_798_exp.pdf

 

[Another Ahab]

Just want to add as a reference here. There are two type of idler pulleys and they require belts of different lengths.
View attachment 873423

That's cool. Did not know the Army was still using the comic book approach to equipment maintenance; love it!

 

[coachgeo]

smart........ they moved the idler off the cover.... too many things on that cover........ it is why it cracks

 

[Mavcaster]

@m-35tom I gather the site you have linked is your own so you'll probably be able to point me in the right direction. I would really like to get the ball rolling on adding a unit to my 1088 while I am in the process of squaring away the cab but just can't do it all at once. A $300 difference for a 8000 BTU gain seems like a no brainer but would like to get y'alls take on pros/cons between gen1/gen2.

 

[m-35tom]

I know several people who have used the 1st gen and been happy. Key to good cooling is insulating the cab. A study by NIS showed that the 2nd gen was 16K btu. I have not found info on the 1st gen but would not believe Red Dot specs

 

[Third From Texas]

My first truck had a Gen1 and it was adequate at best, but that was w/o any insulation. The fellow who purchased the truck from me had it recharged and said that it worked multitudes better so I suspect it was a bit low on juice. But if I were to install an OEM unit, I would lean towards the Gen2.

 

[Keith Knight]

I’m in Florida and I installed a Gen 1, and after trying everything to get it to cool better I gave up and ripped out just the Gen 1 unit and put a Gen 2 unit in and now in here Florida it’s makes it so cold I wish it had a lower than low fan setting.

 

[Mavcaster]

I’m in Florida and I installed a Gen 1, and after trying everything to get it to cool better I gave up and ripped out just the Gen 1 unit and put a Gen 2 unit in and now in here Florida it’s makes it so cold I wish it had a lower than low fan setting.

That’s excellent feedback thanks for that. I’m on the east coast and frequent Georgia where I am from which gets very hot so good to know!

 

[SunValley]

We have installed a couple of the A/C units in to LMTV's. This will require the condensor unit, the A/C compressor, some custom made lines, brackets to mount the compressor and the front crank pulley to run the belt for the compressor. We had to custom make the brackets and the front pulley. If anyone is interested, I can probably make another set, not sure on the cost though.

I’ll take one!

 

[GeneralDisorder]

I’ll take one!

Seeing as that post was nearly 10 years ago and that member hasn't signed in for 1.5 years I find it unlikely you will get a response. Also these parts are much more available now. For example:

LMTV A/C parts

LMTV truck parts

www.lmtvtrucks.com

 

[WassawBound]

View attachment 811062

I'm having to dig into a system installed by a previous owner. Is it safe to assume these relays live inside the evaporator box? I have the gen two unit.

It appears the last guys did a poor job on the install. Naked wires rubbing metal edges in the firewall. I have put gauges on it and it should have enough gas to click on. I can hot wire the compressor and it runs and cools from 87 to 64deg, 61 deg after adding a can. If I short the high pressure switch the compressor clicks on. My switch is binary although my system has electric fans. I'm considering changing to a trinary switch. I believe thats the proper switch for an electric fan setup.

When hooked up my high pressure gauge hardly moves at all. I think I'm dealing with a clogged expansion valve. I heard it's common for systems with expansion valves to move slower though. So maybe I'm not being patient. The low pressure gauge will move much faster that the high side.

So far I've dug up to the TXV. It's located below the brake knobs. I'm just doing a little each day. It's hot as hell here in FL.

 

[WassawBound]

Good to know information for us non master mechanics. I wish the guy before me had use the switch with the shrader valve inline. I guess I'll be adding that fitting later.

 

[GeneralDisorder]

I went with a more common trinary switch threaded into an adapter w/shrader on the drier. The stock military system has seperate fan switch and high pressure switch. I don't think the original systems had low pressure switches. The new systems in the A1P2's have intelligent monitoring boxes that monitor system pressure and temperature.

 

[WassawBound]

I went with a more common trinary switch threaded into an adapter w/shrader on the drier. The stock military system has seperate fan switch and high pressure switch. I don't think the original systems had low pressure switches. The new systems in the A1P2's have intelligent monitoring boxes that monitor system pressure and temperature.

From that Trinary vs Binary video, I gather both types measure high and low pressure. One just has a input from the relay to also control the fan via temp or override switch. In my truck the fan stays on all the time. It's loud mounted on the cab like that. I'm tempted to move it. Sometimes I turn the AC off just so I don't have to listen to it. 1. I may move the condenser down by the radiator like it should be. 2. I may try the trinary switch to see if it gives me a break from listening to it. 3. Do both.

While I have the system evacuated it's the time to get things done. Our alternators are a weak point. So why put that constant fan burden on it if I don't have to?

I ford water way less often than I use my AC. Lol

 

[WassawBound]

I went with a more common trinary switch threaded into an adapter w/shrader on the drier. The stock military system has seperate fan switch and high pressure switch. I don't think the original systems had low pressure switches. The new systems in the A1P2's have intelligent monitoring boxes that monitor system pressure and temperature.

I still haven't figures out why my switch has tripped. If I jumper it the compressor runs. It has plenty of pressure. Now I'm wondering if higher pressure is built up in the dryer but not at my gauges (can that happen) or if the switch has failed. Do these switches need a reset in some way? So many questions.

My local shop won't touch the truck. I've concluded I can probably throw parts at it cheaper than time at the big boy shop.

 

[Another Ahab]

I went with a more common trinary switch threaded into an adapter w/shrader on the drier. The stock military system has seperate fan switch and high pressure switch.

You know "your stuff", GeneralDisorder.

Out of curiosity, where did you pick all of that up?

Just picking up stuff along the way, or are you maybe a former HVAC tech?

 

[WassawBound]

From that Trinary vs Binary video, I gather both types measure high and low pressure. One just has a input from the relay to also control the fan via temp or override switch. In my truck the fan stays on all the time. It's loud mounted on the cab like that. I'm tempted to move it. Sometimes I turn the AC off just so I don't have to listen to it. 1. I may move the condenser down by the radiator like it should be. 2. I may try the trinary switch to see if it gives me a break from listening to it. 3. Do both.

While I have the system evacuated it's the time to get things done. Our alternators are a weak point. So why put that constant fan burden on it if I don't have to?

I ford water way less often than I use my AC. Lol

I went with a more common trinary switch threaded into an adapter w/shrader on the drier. The stock military system has seperate fan switch and high pressure switch. I don't think the original systems had low pressure switches. The new systems in the A1P2's have intelligent monitoring boxes that monitor system pressure and temperature.

I reviewed the diagram. I guess you're right it only says "high" pressure switch. I don't see low pressure mentioned. Do they think you should assume that's a binary switch with both high and low pressure protection? It's hard to know if this engineer had thier coffee that day. Ha ha.