LMTV / FMTV AC Air Conditioner Compressor Mounting Brackets Install Write Up

[Overdrive]

I posted some of this in the AC thread but thought it would be helpful to have its own write-up for the AC Compressor brackets installation. This is a write up using the two key upper and lower brackets used to install an air conditioning compressor on an LMTV. I did this installation on my 1997 A0 LMTV with the CAT 3116 engine.


Installing item #12 (upper bracket) and #15 (lower bracket) in the diagram



Here is the compressor mounted up using the two brackets. CAUTION is required as you are unbolting the left front engine mount bolts for the lower bracket, a few front engine cover bolts, and unbolting the ONLY two bolts that hold your air pump/power steering pump to the front cover/engine.

In the diagram for the brackets it shows a spacer (item #14) inserted on the rear engine mount bolt between the block and the lower bracket. I need to find a suitable washer or spacer and stick it in there. As it is, you MUST NOT TIGHTEN the lower bracket bolts (2 engine mount bolts) until you have ALL the upper bracket bolts installed (engine cover, pump) and attached to the lower bracket loosely otherwise you will be cursing and trying to use a pry-bar to get the lower and upper bracket bolts to match up... Don't ask me how I know this, Jedi training



I used longer metric bolts (of the proper strength same as the factory CAT bolts) for all the engine cover and pump bolts since the upper bracket adds about a 1/4". be VERY careful to not jar the air compressor loose when doing this. My Air pump did not move when I unbolted it but do this at your own risk since yours may move. Also, the threads on the lower bracket that attach the upper bracket are easily stripped. I stripped one and was able to drill it out and put a nut on the bolt. You can see the three grade8 bolts with the 4th hole the one I stripped.

I eventually routed the big wire loom behind the bracket for a cleaner appearance and to not pinch anything.


Pic of two longer bolts I used for the Air Pump.

It looks like ALL the threads on the upper bracket are clogged with powder coat and machining residue so you MUST chase them with a tap or you will mess up your bolts/threads.

For the AC compressor to upper bracket and upper to lower bracket I used SAE bolts. All other bolts already on the truck were metric.




When your done please be sure to torque your two left front engine mount bolts... Actually check them ALL since I found all of mine to be scary loose.



You MUST torque the engine cover, air pump, and engine mounts to spec... you do not want your air pump coming loose going down the highway. It is REALLY tight in there once the brackets are in place but I was able to torque those bolts.


I hope folks find this helpful.
OD

 

[Overdrive]

Pic of the installed compressor with the cab down and lifting up the side skirt from the cab.



Pics of the lower (green) and upper (black) AC compressor brackets


Pic of the lower bracket installed

 

[MGKMartin]

Thank you for the great write-up!

 

[NDT]

Can you do us a solid? Please list all the bolt sizes you had to buy and quantities? Thanks, save us from reinventing the wheel a third time.

 

[mkcoen]

Great write up. Now I'm sufficiently concerned about doing this myself though. I'm pretty good at "here's a part. Put it there. Plug it in. Start the truck." I'm going to be studying this long and hard before I dive in to it.

Has anyone had luck locating the condenser brackets? Those and dryer are all I need for t he complete set.

 

[Overdrive]

Its not too bad of an install just takes a lot more time than you would think. Not technically challenging really just being aware of what your messing with. Its interesting to be standing between the tire and the frame to get at the brackets but once you get over that you should be fine.

Go ahead and give it a try with just installing the lower, green bracket first. Its only the two left front engine mount bolts. you don't have to replace the bolts with longer ones and its pretty strait forward. Just remember if you do the lower bracket only, when you do go back and install the upper bracket you have to loosen those two engine mount bolts or things won't line up... I still need to put a spacer/washer on the rear bolt to match the thickness of the trans cooler bracket that attaches to the front engine mount bolt. In the parts diagram it shows a little "U" spacer between the lower bracket and the engine block.

Sheeze, you guys want bolt info as well
I had to make two trips to HD for bolts of course. I originally thought some of metric ones were SAE so you know how that goes.

You need:
Two longer air pump bolts (metric): M12-1.75x80mm Grade 10.9


Two longer front cover bolts (metric): pic shows the stock bolts I went with 35mm and 40mm. Decided to use the longer ones (M8-1.25x40mm class 10.9)


4 AC compressor mounting bolts (SAE) (if you want to mount a compressor but not needed just to install the brackets): 3/8" x ? can't remember - long enough to go thru compressor mounting holes and a good 1/2" into the upper bracket.
4 bolts (SAE) to mount the lower to upper bracket: I think these are 3/8 coarse thread 1 or 1-1/4"

That should be it on what bolts you need unless you strip out one of the 4 threaded holes on the lower bracket like I did. The popular guess is that the threaded holes on the lower bracket are using grade 5 nuts welded on there so when you use grade 8 bolts to mount the upper to lower bracket you can easily strip the bolt holes... just be careful and don't torque down too tight on those 4 bolts.

TORQUE ALL THE BOLTS TO SPEC (you can find torque specs in the TM for the various bolt sizes, M8,M12, 3/8, etc).


OD

 

[Overdrive]

Of course now that I have divulged all the "secrets" your going to install your brackets and say, come on OD it took me 15 minutes dude!

 

[Rage]

Can someone please tell me how you routed the belt in this install on a 95 m1078. Or where you got the drive pulley for the crank shaft? I'm completely lost on this part.

 

[tburk49760]

I need the crank pulley, compressor and idler. Help! Summer is coming and it gets very hot here!

 

[mkcoen]

I've seen that set of stuff on the favorite on line auction site several times in the past month.

And please. Spokane gets hot? Yakima I might buy (since I lived in both). When it's 90 from late April until early November then you can start saying it's hot. Now me? I need to get my AC in.

 

[tburk49760]

I'm a bit of a sissy and we get near 100 for two months! But it's a dry heat...I do drive mine about 200 miles a week though.

 

[Overdrive]

I am being secretive on this to not get hopes up too early but I have a prototype crank pulley (A0 3116) machined from a "secret" partner Should be getting one in a few weeks. I have my hands on what I believe is the correct crank pulley for the A1 trucks with the 2 belt setup but that's another covert op right now.

There is something strange about the "kits" that are on eBay concerning the crank pulley but I don't have definitive info on that.

I promise when I get something working I will divulge the juicy details.

OD

 

[Rage]

OverDrive once you have a working crankshaft pulley for the 3116 I'll take one.


Sent from my iPhone using Tapatalk

 

[lmtvjunky]

Crank shaft pulleys???? Who the heck has those?

 

[scottmandu]

Crank shaft pulleys???? Who the heck has those?

I've got a dozen of them.

 

[scottreb]

I've got a dozen of them.

Which engine?

 

[Rage]

If you have them for a CAT 3116 I'll take one

 

[mkcoen]

OD are you going to merge this thread with your other AC thread? Keep all the info in one spot?

 

[Overdrive]

I could but it would be very crowded

No joy on brake lights yet. No power at brake switch when lights set to stoplight and the relay has no power... time to breakout the -20

 

[mkcoen]

I could but it would be very crowded

Actually I was just thinking copy your bits specific to your AC work not the extraneous stuff from us peons.