AC install on 923A2

[74M35A2]

The compressor comes with oil as long as it was still sealed and not spilled out. That is enough oil for the components and system it was designed for. If you added longer hoses or a larger condenser/evap, I would probably add a little more.

Should be a single wire going to your compressor clutch. It should come from a system relay or at least a system pressure switch. Power flow should go like this: From battery to A/C control panel, then out to condenser and evaporator fans. Also out to pressure switch(es). From pressure switches to compressor clutch. May be up to several relays, but general flow is the same.

 

[Buffalobwana]

Finished up wiring. I took my ignition wire on the AC switch harness and attached it to the wire labeled 5C coming off the fan switch. Put the multimeter on the wire to verify, then tapped into the line with the T-adapter included in the packet.

Connected compressor wire to wiring harness and connected +/- to battery per directions.

Flip on on the master and the fan speeds work as they should.

Came me in for lunch and ups man promptly delivered vacuum pump. Ate, read directions, vacuumed lines for 15 min. Took note of gauges and left if off for 20 min. Came back and needles had not moved.

Turned vacuum back back on and went to Walmart for the R-134.

came home and saw pump was overheating and going in and out. It's only 100. Crappy Chinese pump! Ok, start over, put wet towel over fins and a fan on it and vacuum for 30 more min

Ok, time to add r134. Connect can to line. Try to bleed air ... Hmm problem with the line or fitting. I jack with it. Content that I'm good, I open low side up. For some reason I decide I need to bleed more, so I depressed the Schrader valve and promptly lost my vacuum. Instead of bleeding r134, I let air suck in.

£#€¥

start over. It's vacuuming now.

 

[Buffalobwana]

FYI, I'm doing this because I could only find one thread on installing these. I know a dozen guys posted that they had done it, but didn't write it up. I had one post to read to help me with this, and that was from "Over". So, I'm putting out some mundane, but hopefully helpful info to the next guy who wants to do this.

 

[Buffalobwana]

Huge shout out to 74M35A2 he walked me through troubleshooting the system!

Ok, it's all done. Wires, hoses, parts all where they should be. Had an issue with the crappy Chinese made manifold gauges I bought, but fixed them. At $125 for the set, they weren't exactly cheap, but obviously, not exactly quality either.

Sat in WalMart parking lot adding 134. Put a ton of r134 in it. It kept dropping down to the teens on the low side and pressures were below norm on high side, so I kept walking into Wallyworld and buying another can. (And digital thermometer)

Pressures finally stabilized on low side at 35+/-, but never got high on the "low" side. High side pressures range from 210-300 depending on fan. Low side is 35-40. At 80 deg outside. Seemed reasonable.

I suspect that the fans are set to kick on at 20 bar and off at 15 bar, which is about 280 and 215 respectively. It can't be a coincidence that this is the exact pressure that it flips on/off. Anyway, that is what it does. Fans kick on for 7 seconds or so, whatever it takes to get to 15 bar, then when it hits 15 bar (215psi) they turn off.

Sitting in in the pkg lot, I finally got 45.5 degree air from the unit and the low pressures were stabilized and not moving, so I stopped stuffing freon in it.

To to me it seemed like an excessive amount of freon at 2-16oz and 8-12oz, but, that's what it took to get to this point. I'll drive it with gauges attached this evening, see if the hotter weather gives me Overpressure on high side.

 

[Flatlander]

Nice! What length belt did you end up using? Do you have to re-route the belt in any way?

 

[Buffalobwana]

I don't know the length of the belt, I ordered the belt that 74M35 had in the photos of his instructions. I did route the belt differently than instructed. It gives more bearing surface on the alt and compressor.

Around alt, back in to tensioner, back out to compressor it fits and gives a good amount of surface on the two. This route can not be done if you leave the tensioner as stock. You have to take it off. Remove the tab and re-drill the index hole.

Works great. 10 months later and no issues.

 

[Buffalobwana]

Here is the routing I used. Note the position of the tensioner is rotated about 100 degrees from stock. Works great
.

 

[Buffalobwana]

The alt and compressor have about 180 degrees of contact with this routing method. Pulls against the newly indexed tensioner in a straight line. The tensioner wasn't indexed to this position, it was indixed to about the 6:00 position, and pulled up to 8:00 position with tension.

 

[Buffalobwana]

One year update.

Should have put a generous blob of dielectric grease on every electrical plug fitting. These fittings must have gotten a little oxidation on them, as I had problems from the beginning with getting the compressor to come on at all.

All of these plugs come together at the evaperator right about where the drivers elbow is. One day I touched my elbow to the wires and got a bit of a burn. The power plug, just a simple positive and negative plug, was so hot it had discolored the Red positive wire. I cut it off and connected with heat shrink crimps with 10 ga wire I picked up at the next store. Overkill, but, I thought if it's running that hot, 10 ga can't hurt.

When I went down to Houston to do deep water rescues, I greased the heck out of all the exterior plugs at the condenser and dryer receiver. Voila, the compressor issues were resolved. Made me feel dumb for missing this simple diagnostic trick from the beginning.

Anyway, these units are 10 years old. Grease up those connections, and it will fix any past issues, and help protect against future issues.

Just replaced the air filter, on eBay $11-$35 each. There is a difference in quality, but the $11 looks ok.

Its still blowing super cold air and it's still the best upgrade I have done to the truck.

 

[74M35A2]

The reason it is the best thing you've ever done to the truck is because of the high speed 8.3L A/C compressor bracket. Ultra yummy. They're those that have them, and those that do not.

 

[Buffalobwana]

True, true.

 

[74M35A2]

Just kidding bud.

 

[Over]

One year update.

Should have put a generous blob of dielectric grease on every electrical plug fitting. These fittings must have gotten a little oxidation on them, as I had problems from the beginning with getting the compressor to come on at all.

All of these plugs come together at the evaperator right about where the drivers elbow is. One day I touched my elbow to the wires and got a bit of a burn. The power plug, just a simple positive and negative plug, was so hot it had discolored the Red positive wire. I cut it off and connected with heat shrink crimps with 10 ga wire I picked up at the next store. Overkill, but, I thought if it's running that hot, 10 ga can't hurt.

When I went down to Houston to do deep water rescues, I greased the heck out of all the exterior plugs at the condenser and dryer receiver. Voila, the compressor issues were resolved. Made me feel dumb for missing this simple diagnostic trick from the beginning.

Anyway, these units are 10 years old. Grease up those connections, and it will fix any past issues, and help protect against future issues.

Just replaced the air filter, on eBay $11-$35 each. There is a difference in quality, but the $11 looks ok.

Its still blowing super cold air and it's still the best upgrade I have done to the truck.

Hi..I was looking thru my old AC install post as I'm starting to put one of the M915 kits I have into my newly acquired pair of M923A2's. Your tips are great! I believe I bought the same Compressor brackets but were sold on EBay. Printed up your tension er mod. Have a great New Year (2019)!!!!!!!

 

[Buffalobwana]

Thanks Over, it was your post that helped me get through my install. Many props to you for blazing the trail for me. I had never touched an AC system, and now I feel like a pro!

On the belt routing, I route mine differently than ‘74M35 (who sells the AC brackets) does. On my route, I don’t believe re-indexing the tensioner is necessary.

This was an oversight on routing that wound up working well as it gave everything a better grip on the belt. BTW, I have a really good compressor if you need one.

 

[Buffalobwana]

Two year update. Since we are on the subject ...

fired it up in November, a slightly warm Nov day, and the AC was just blowing air.

“Well, crap. I bet a rat got in there and chewed my hose somewhere!”

I looked around. No rat damage. So I started back with the electrical. Sure ‘nuff, the signal to the compressor was compromised at the plug coming off the pressure cap. Wiggled and did the “plug and unplug” about 20 times to scrape off any corrosion and ... boom, back in service!

Blows cold air still. Best investment in the truck! Even better than the air ride seats, and I love my air ride seats!

 

[74M35A2]

Thanks for the updates. Glad to hear everybody likes their 8.3L compressor brackets. Yes, I do sell them on eBay for the same price as here.