A/C Question

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Topic author
1979bettywhite
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A/C Question

Post by 1979bettywhite »

So when I bought my 78 Chief, the factory A/C would blow, but not cold. I finally got around to inspecting things. I found the wire leading out of the york compressor disconnected via a failed crimped connection. I consulted my TSM wiring diagram and found that the brown lead should go to the compressor. And of course, close to that failed crimped connection was a brown wire with exposed copper.

So I tested the connection and found 0 volts when the A/C system was off, and 12 volts when turned on. So I clipped both ends and reconnected the wire. Now the clutch spins when the A/C is switched on, and when off, it of course does not spin. There is also plenty of movement in the sight glass now with the system in operation.

Air seems to be a little cooler, but definitely not cold.

Along the line somewhere someone had converted the york compressor over to 134a. At least that is the low pressure port that is installed on top of the unit.

So I figured I would try one of the refill cans from the auto parts store with a pressure gauge and see what that does. So I cranked the chief, turned the A/C on full blast and connected just the gauge to the low pressure port.

Read 0 on the gauge, but it also seems as if the connector is not piercing the port in order to read the pressure. I am thinking in terms of when you check pressure in a tire etc. You just know there has been a plunging of the valve stem to allow pressure to be read and added. Did not seem to get that feeling.

So I probably should not have done this, but I went ahead and attached and pierced the can to add 134a to the system. Figured I could still read the pressure if there was any just by having the connector hooked up, and potentially add some refrigerant and see if the pressure changed.

Well sure enough, I tried to squeeze the trigger for maybe a second or two and release it, and the gauge went immediately into the red pressure reading. But it feels like no refrigerant is flowing out of the can, which goes back to my prior thought in that the gauge was not interacting with the needle in the pressure port enough to open the port and read the pressure, as well as not opening the port to add any refrigerant.

So my question is, am I missing something in getting the low pressure port to open to be able to read the pressure as well as add refrigerant?

This is my first time dealing with A/C, so I don't know if I need to open the port manually somehow or what?

Any thoughts?
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tedlovesjeeps71
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Re: A/C Question

Post by tedlovesjeeps71 »

Does the replacement air can just push-click over the fill port or does it screw on?


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babywag
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Re: A/C Question

Post by babywag »

oljeep.com has real manuals for download. I'd @ least read up some before trying anything.

If stock, the service valve needs to be manually opened for charging.
-Tony
'88 GW (aka Babywag)

SJTD
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Re: A/C Question

Post by SJTD »

If it has the valves on the compressor ports the one you are trying to fill through should be turned a few turns, not until it stops. If bottomed it isolates the pump from the system.

I think the gas would have still gone it if you had it bottomed but it would be flowing backwards. Maybe the expansion valve acts as a check valve and can't flow backward?
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

Topic author
1979bettywhite
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Re: A/C Question

Post by 1979bettywhite »

Figured pictures are better than words, so here you go:

ImageImageImage

You can see the fitting is an r134a fitting. My question is one I attach the filler hose to it, do I need to loosen this fitting to "engage" the system? For lack of a better term of course.

I do have my TSM from the site. I will go back and read it. Just figured it would be of no help since this has been converted over.

Thanks.


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tedlovesjeeps71
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Re: A/C Question

Post by tedlovesjeeps71 »

I believe what you want is here:

Image

Attach the fill hose as you were. The thing in yellow is a cap. Remove it to see the valve. I think you turn it in (clockwise) to open and allow filling. Close it after filling and then remove filler hose.
Hopefully someone can confirm or correct me if I'm wrong.


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candymancan
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Re: A/C Question

Post by candymancan »

Yea you need to take that cap off. and get a pair of locking vice grips or the correct wrench and turn that knob under the cap circled in the pic above maybe 2 or 3 turns to open the valve. This will allow you to get a pressure reading and also allow you to put in refrigerant. But only open it if you have a gauge or refill can attached.. Otherwise itll blow refrigerant everywhere lol

also you positive someone converted it to 134A that looks like its still r12 to me. 134a in a r12 system can cause an explosion just an fyi. They might have put a 134a port on it but everything else still looks original to me..

also the sight glass should have no bubbles when its full. If youre seeing whitish bubble flowing then its a can low.
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

Topic author
1979bettywhite
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A/C Question

Post by 1979bettywhite »

So if I attach the gauge, remove the cap and open the valve I should at least be able to check the pressure right?

And no, I am not 100% sure it has been converted. Just figured it was since it has the port. Figured why would someone put that on without converting it at the same time. But I guess I should never assume anything.

Is there a way to check and see what's in it?

Thanks for all your help guys.


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tedlovesjeeps71
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Re: A/C Question

Post by tedlovesjeeps71 »

1979bettywhite wrote:So if I attach the gauge, remove the cap and open the valve I should at least be able to check the pressure right?

And no, I am not 100% sure it has been converted. Just figured it was since it has the port. Figured why would someone put that on without converting it at the same time. But I guess I should never assume anything.

Is there a way to check and see what's in it?

Thanks for all your help guys.


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Yes, there is a machine that can tell you what is in the system. Unfortunately, it's going to be at an AC shop (if they are legit) and probably will charge you to hook up to it.
As far as being converted, it's a crapshoot. You can simply buy the "conversion kit" that comes with the can of refrigerant. Unscrew the R12 port, screw on the 134. Some folks only go that far and fill it up. That isn't removing the old freon or its oil. They are not compatible which is why a real conversion is so expensive. You can cheat and do various levels of parts replacement but results will vary.
Hook up the hose, open the valve, and check the pressure.


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candymancan
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Re: A/C Question

Post by candymancan »

I put a 134 port on to simply check the pressure because i didnt have any r12 gauges. But yea you can put a gauge on open the valve to check your pressure

Im not sure if there is a qay to check if you had 134 in the system but a shop migjt have a machine to chexk. But that compressor and fittings and hoses look r12 to me. And 134a in r12 hoses is kinda dumb anyway 134a molecules are smaller then r12 and require new hoses and a r12 compressor from what i read cant run r134a properly even if the oil is changed to pag oil.


I dunno. If youre not certain if it has r12 or r134a id probably put r12 in it myself. But it might be best to have a shop check whats in it before you start putting 134a in. and find out you have r12 in it.. Tbh it might be best to do this..


another route is to buy the buton.propane bittles. They are often labked as R12A note the A its a flamable mixture but its a refrigerant and its been used wayy before r12. They use it in other countries but the USA is too afraid to use it due to it being flamable. I bought 3 cans myself put two in when i got my wagoneer and compressor kicked on and i had cold air. it can be run with r12 or r134

Only issue is its not compatible with butyl rubber hoses a d i heard thats the hoses we have..
Last edited by candymancan on Thu Aug 31, 2017 7:22 pm, edited 2 times in total.
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
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tedlovesjeeps71
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Re: A/C Question

Post by tedlovesjeeps71 »

Real shops have machines to iD the type of freon. They have to because if the evac a system with R12 it will contaminate the 134 or the new stuff. That ruins the stuff in the holding tank and it's stupid expensive to clean the recovery machine.


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Topic author
1979bettywhite
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Re: A/C Question

Post by 1979bettywhite »

Thanks for that input Ted and Candyman. I will see if I can find a shop to test it before I add anything to it.

I went back and read my manual tonight (yes, I should have done that beforehand). Things really should be tested with a compound manifold system in order to read both the high and low side pressure. I of course don't own one.

I would like to get the A/C working as is if possible. The first shop I took it to told me not to mess with it and just buy a newer aftermarket system. I know that is probably a better decision for efficiency etc., but just don't want to spend at least $1,500 getting a new system and having it installed. If someone can diagnose this system and service it to get it back to decent operation that would be fine with me as long as it doesn't cost me an arm and a leg.

I have heard conversions to 134a in the york compressor are just so-so on cooling. R12 was much better I hear. So even if someone converted it to 134a it may not even be worth messing with.

Just figured I would try to get some cold air back in the Chief :)

candymancan
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Re: A/C Question

Post by candymancan »

Meh f the shop who said not to mess with it. If it has r12 in it. buy two cans of r12,for 30$ each and put em in and call it a day.. Thats what i did.. My leak is ao small it lasted a year ina half b4 i needed 1 new can.

Or just get the propane.butane R12A.

i wouldnt spend 1500 on a new a.c system either lol
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
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tedlovesjeeps71
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Re: A/C Question

Post by tedlovesjeeps71 »

This is how a real shop will ID the refrigerant.
Image

That's the only way I know of to be certain.
The other option is to evacuate your system as much as possible, change your accumulator and Rec/Dryer, and fill with new. A shop may evac your system via vacuum but if they don't have an R12 system, they may not be able to help.



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SJTD
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Re: A/C Question

Post by SJTD »

If a reputable shop did a conversion to 134 it should have flushed the system, installed PAG oil and applied a label indicating the new refrigerant.

If you can't get the gas identified the only safe alternative is to assume it was properly converted with PAG oil and to install R12 or one of the hydrocarbon replacements. They can be used with the PAG oil but 134a can't be used with the original mineral oil.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

Rod2
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Re: A/C Question

Post by Rod2 »

1979bettywhite wrote:.......I have heard conversions to 134a in the york compressor are just so-so on cooling. R12 was much better I hear. So even if someone converted it to 134a it may not even be worth messing with.
Just figured I would try to get some cold air back in the Chief :)
I have 134A in my York and it is plenty cold for me and her; on high, it puts out 45* air. Sometimes, I can't turn it weak enough. But I have a waggy unit in my J-truck, so I'm cooling about a third of the cubic space.
Just cool it!
'73 J4000 'WOOD GO' 360, 2100 MC, T-18, D-20, 60-2 rear, D-44 closed knuckle front with Warn lock-o-Matics, Eaton E-lockers both, Pertronix module, AC, PS, Hydro-boost, AirLift bags front and rear, 33x15 Goodyear MTR's, Pacer 15x8 aluminum Bullet Holes, Summit line lock, 3rd brake light, tilt column from '77 Firebird, 12000 MileMarker on cradle, hitch receiver on both ends

letank
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Re: A/C Question

Post by letank »

the OEM system with R12 looks like this, with a sanden compressor -not mine, scavenged from a donor-

Image

so plumbing looks retrofitted

As for R134, because of higher pressures, hoses might be challenged -I blew one fat hose upon recharge- still no AC for me.

The vintage air kits are supposedly the best, but do not really fit our underdash esthetically

check these picts from bjs' site

http://www.bjsoffroad.com/Complete-Air- ... p_873.html
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)

Topic author
1979bettywhite
Posts: 547
Joined: Tue Jul 25, 2017 8:14 am

Re: A/C Question

Post by 1979bettywhite »

After taking a year off the A/C project, I am now back on it. Here is what I have done so far:

Took everything to a reputable shop to have a look at things, and give advice and direction on what I need to do to fix things and get it operational again.

They were not thrilled with the operation of the switch, nor the thermostat, so they ordered new ones for me. I replaced those along with all the wiring so I now have fresh contacts. Put everything back together and took it back to the shop. We evac'd everything out and put a vaccuum on it. Held vaccum ok, so we then decided to start filling it with 134a with some dye and see if we had any leaks. Of course we did find a good size leak in the discharge hose right at the compressor. So they evac'd the remaining refrigerant.

So I went to remove the discharge hose from the compressor and the evaporator core. Let's just say that after 40 years, those connections weren't coming apart easily. So lots of PB blaster and about a day of patience and I was able to break them loose. Took the hose to an A/C parts shop and had a new one made up in an hour.

First shop told me to extract all the oil I could out of the compressor and refill it with PAG 100 oil. So I took my vacuum pump and some vinyl tubing and extracted as much as I could with the compressor still in the Jeep. Not an easy thing to do. Refilled the compressor until I had about 1 1/4" of oil from the bottom.

So at this point I feel like I can test the system again and check for leaks. The only leak we had before was at the discharge fitting at the compressor, so I don't expect any more leaks.

So my questions for our A/C gurus are as follows:

I got all the oil I could out of the compressor, but there might have been some residual oil left in there. Will it hurt too much to put some 134a in the system to check for leaks?

Also, I have read basically everywhere that you need to change your dryer out when converting over to 134a. Shop also told me I might blow my dryer at some point as well, so I guess there is truth to that. On my 78, the dryer sits behind the grill on the passenger side and look like it will be a bear to remove. Not to mention trying to get those flare connections loose. If my intent is to put R12 back in the system after determining if I have any more leaks, do I still need to change the dryer now? I.E. Is running 134a through the system for a total of a a couple hours going to hurt the dryer enough before switching back to R12? (I do plan to go back to a POE oil if I go back with R12)

Would be really nice to restore this old factory A/C system, but the farther I get along in the project I keep wondering if maybe it would have just been better to rip everything out and go with an aftermarket system......

letank
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Re: A/C Question

Post by letank »

it is a rule to change the dryer which double as a filter, anytime the system is converted or has been left open to air , in your case a year or so...
yes the dryer is a pain to remove... I could not remove mine, even w pb blaster, the location is so tight thag too much force applied wrongly will twist the AC tubes.
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)

Topic author
1979bettywhite
Posts: 547
Joined: Tue Jul 25, 2017 8:14 am

Re: A/C Question

Post by 1979bettywhite »

So I am guessing you never got it out? Are you using your A/C system currently with the old dryer?


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