P9106 Getting AC...part list?

[79jasper]

What's interesting, is a lot of the enviro-safe says don't pull a vacuum.
They say if you plan to pull a vacuum, use the industrial R134A replacement.

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[Greg5OH]

i dont see anything on their website that has a refrigerant made for r12 systems though?

 

[Greg5OH]

tomorrow picking up a complete factory 91 AC system. whoel compelte truck was in the yard. $200 for it all . will just put new o rings into all the connections.

did some more research, looks like I will probably go with R12A. I need an oil for it too though still ya? I believe these trucks call for 10 oz ester oil. How do I get it into the system?

 

[HS108]

I'd still flush it, but good find

 

[Greg5OH]

Since all the lines will be disconnected I will definitely be running a bunch of denatured alcohol through all the parts. put some 40 psi shop air through em all as well. Then jsut add 10 oz of ester oil to the system ya? people say to put it into different areas on a dry system, so say 2 in evap, 2 in condens, 1 in drier, and the remainder into the compressor?

 

[HS108]

That's what I did, just spread it throughout the system components

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[Greg5OH]

Where does the oriface tube go?
Also, there are two decent sized wires going to some kind of switch on the drier. WHat is that, and where do those wires connect?

 

[The Warden]

Where does the oriface tube go?
Also, there are two decent sized wires going to some kind of switch on the drier. WHat is that, and where do those wires connect?

The orifice tube goes into the pipe on the receiver/drier right where it connects to the hose that goes to the condenser.

I just realized that I don't think anyone said this yet...DO NOT REUSE THE RECEIVER/DRIER!! Buy it new! Basically, every time you need to open up the air conditioning, replace the receiver/drier.

The switch on the drier is the pressure cycling switch. The feed wire goes into the cab to the HVAC controls; the other wire goes to the compressor clutch. Basically, the switch cycles the compressor on at a specified pressure...when the pressure drops down to a certain point, the switch breaks the connection and the compressor clutch disengages. After the compressor stops pumping, pressure on the low side will slowly build back up until it triggers the switch to send power to the clutch, engaging the clutch and cycling the compressor again.

You can (and, especially if you run anything other than R-12, you should) get a switch meant for R-134a that has a small screw in the middle that will let you adjust the pressure as needed. I don't remember what pressure it should be cycling at, but you should be able to find it easily enough, or maybe one of the A/C experts (@chris142, maybe?) knows off the top of his head.

One thing to note...when you first start to add freon after evacuating the system, you'll need to unplug the switch and put in a jumper wire to get the compressor to engage. Once you're regularly seeing enough pressure on the low pressure side of your gauge for the compressor to cycle normally, then you can remove the jumper wire and plug back into the switch.

Hope that helps some...good luck!

By the way, before you do the install, I would strongly recommend taking a look at the R-134a condenser and comparing it to the R-12 condenser. The visible efficiency differences are really night and day...and, it's worth noting that @HS108 has a factory R-134a system; I don't think there's any way to get 40 degree temperatures running R-134a in a system meant for R-12...

 

[Greg5OH]

i wont be running r134a though, I will be running r12a.
Also the condenser is larger because r134a is less efficient, so it needs more surface area to exchange heat.
Not buying any new components other than the drier, which has the dessicant in it and indeed should be replaced. 16 bucks only. New condenser is liek 75 though, which was main reason of going with a complete factory take off system.

Alos, thanks for clarifying about the pressure switch. It should be already an R12 switch, since its from a 91 truck, I am hoping.

So I have my AC compressor power wire, goes in to one side of the switch, out of other side of switch, runs to the compressor, and I assume the other side of the switch on the compressor is just ground yes?

 

[junk]

I get 40 degree air from my R-12 system running R134. My system is 100% new aftermarket parts. I do have a remanufactured compressor on it. This is in my 89 ford. Only original part was the pressure switch on the drier. I did adjust the cycling point lower for R134, but that was years ago no.

I don't remember what color O-tube I have installed. I think it is red.

I charged my R-134 until the vent temp and the drier matched temps. So vent temp was 32 and drier body was 32. I get condensation back to the compressor.

I know every ones says to keep R-12 in an R-12 system, but I've had great luck with the conversions.

Jeremy

 

[The Warden]

i wont be running r134a though, I will be running r12a.
Also the condenser is larger because r134a is less efficient, so it needs more surface area to exchange heat.
Not buying any new components other than the drier, which has the dessicant in it and indeed should be replaced. 16 bucks only. New condenser is liek 75 though, which was main reason of going with a complete factory take off system.

Alos, thanks for clarifying about the pressure switch. It should be already an R12 switch, since its from a 91 truck, I am hoping.

So I have my AC compressor power wire, goes in to one side of the switch, out of other side of switch, runs to the compressor, and I assume the other side of the switch on the compressor is just ground yes?

Oh, okay...I don't believe the "A" designator is correct in "R-12", so when I read your earlier post, I thought it was a typo and you missed the "3". That's what I get for assuming I still contend that the added efficiency from using R-134a components would benefit even a system running R-12 (the plate-style condenser is far more efficient at heat transfer than the tube-and-fin condenser), but it isn't as important in this case.

As to the power wire, yes, the other side of the switch on the compressor goes to ground.

The switch may be worth replacing anyways; they can and do go bad. On the other hand, finding a switch meant for an R-12 system may not be the easiest thing these days...

 

[MTKirk]

that enviro safe stuff is definitly cheaper. and says it works the same in in r134 and an r12 system.

I have it in my truck & it works great! I put in rebuilt compressor, new drier, new orifice, flushed all my old stuff, put in new o-rings, added PAG oil, and enviro-safe.

 

[Greg5OH]

alright so, i have almost all the parts and will be putting them on this week.
what is the charging procedure?
vacuum the system down...

Do I attach the manifold gauges (red to high side, blue to low side, and yellow to vac pump?)

vacuum it, make sure it holds, preferably overnight.

then i add refregerant to the cold side? To do this i disconnect the vac pump from yellow hose and screw on a can, then open the low side valve on manifold?

jump the compressor to make it turn on?

With the R12a I know I need 2.5 cans to equal the proper charge of fords spec of 44oz

(and 10 oz mineral oil will already be in the system)

 

[junk]

Procedure sounds good to me.

Connect gages, open valves, pull vacuum, make sure it holds vacuum, turn off gages, connect can of refridgerant, open low side to fill.

You can jumper the compressor to run if you want. I typically don't. I just fill refrigerant until it starts cycling on it's own. It will help feed refrigerant if you place the cans in warm water while you're emptying them. Also keep them upright so you fill vapor. If you turn them upside down you will fill liquid and that's bad for compressor I'm told.

I was thinking the a/c compressor clutch wiring has some sort of diode thing on the wiring harness too it. No clue if it's needed with your setup since you're all custom wiring. Just thought I'd throw it out there. No clue what it does.

- Jeremy

 

[79jasper]

I didn't have to jump mine.
I put in most of first can with engine off.
I soak all the cans in warm water.

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