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[ferretjuggler]

I keep reading that the refrigerator gas used in the 1970's Wagoneers and CJ's is no longer available,  due to some pathetic whinging about the ozone layer or something

So is anybody actually running a'70's Jeep with the Air Con that still works OK?
I see plenty advertised for sale with non functioning air conditioning.

Presumably modern gas don't work in the old style system 

Alternatively,  has anyone managed to transplant the system from a more modern vehicle into an oldie?

[Bulldog67]

Would be a nice luxury but im resorting to 3 plug in fans

Pretty sure dj20 has aircon

[wildwood]

Should be doable cos when you break it down there are few items to an AC system....
Main one is where to mount the pump and that has been taken care of by Mr Jeep since way back.
The drier and heat exchanger/ rad are obvious as to where to put them......
The rest is probably a complicated mass of wires relays switches and plumbing.....and I think that is what scares most people off. But if you have a nice nakeeed vehicle from which to start it can only help.

[ferretjuggler]

Should be doable cos when you break it down there are few items to an AC system....
Main one is where to mount the pump and that has been taken care of by Mr Jeep since way back.
The drier and heat exchanger/ rad are obvious as to where to put them......
The rest is probably a complicated mass of wires relays switches and plumbing.....and I think that is what scares most people off. But if you have a nice nakeeed vehicle from which to start it can only help.

I can remember about 40 years ago my old physics teacher describing a domestic fridge as a simple heat pump.
Not sure how/what the drier does on an air conditioning system.
Presumably it removes moisture to stop the cooling element from icing up
Maybe a little research is in order.
I also read recently that the new A/C systems are far less power sapping than the old ones.

[The Transporter]

There is no reason why your aircon can't live again... You have two options, both of them are pretty simple jobs... up till about 1993 the common automotive refrigerant was R12....It was a superb refrigerant but the tree huggers hated it.... This was replaced by R134a and is still the current refrigerant though they do plan to replace this in the next few years..

R134a can be put into an R12 and it will work just as well but the issue is the lubricants used. R12 used a simple mineral oil but mineral oil is not micible with R134a and eventually will turn to gloopy sludge....Most aircon compressors are lubricated a bit like a 2 stroke so it is important that the oil can mix with the refrigerant...Only the York recipricating compressors have an oil sump.

So! How do we make an old system reliable? You can either strip down the aircon system and flush out the old mineral oil (I use solvent based brake parts cleaner) from the pipes, and heat exchangers, remove the compressor and turn it over by hand to get the bulk of the oil out, rebuild, fit a new drier add PAG lubricant (Same ammount as there would be mineral oil) and have someone charge the system  with R134a....This takes a little care as the system will need a little less R134a....And you are done!

Or you could take a short cut and find a fridge man who has a bottle of Isceon49,(R143a) which is a blend refrigerant of R134a and a carrier agent to allow the refrigerant to mix with the mineral oil..

I have come across folk who have used a mix of Propane and Butane and although it works very well indeed the consequenses of developing a leak in your aircon system are pretty scary

The purpose of the drier is to ensure that there is no moisture inside the refrigerant circuit though if the system has been properly evacuated any moisture should have boiled off in the vacuum applied.. In the days of R12 any moisture in the system would mix with the refrigerant and for acid that would corrode the inside of the aircon systems, they also act a a small reservoir for refrigerant.

There are two systems that have been in common use in car air conditioning, one uses an expansion valve that controls the flow of refrigerant through the evaporator inside the dash, the evaporator temperature is controled by a thermostat measuring the temperature of the evaporator, the other is the Fixed Orifice type system where the refrigerant is forced through an orifice tube and evaporatot temperatures are controlled by the measuring of suction pressure

The XJ uses the fixed orifice tube system..

[wildwood]

That was the compressor I was trying to remember
YORK
Huge monster of a thing and quite a few are being used for filling air tanks for tyre inflation.....
They were use on trucks and I've seen them stuck under the hood of a Mustang '67

[The Transporter]

Yeah my old Range Rover in Dubai had a York...Good tough compressor but sounded like a single cylinder motorcycle.... My pal has one on his Humber Imperial V8 marked up as a Mopar (May be slightly different but it has been a long time since I have worked on a real York)compressor...Still works perfectly though it does need a top up every couple of years as that can leak a bit

The RangeRover would freeze your knees and roast the rest of you and at 110 mph the tops of the doors would suck open and let in hot air (It was a 2 door)

[ferretjuggler]

Thanks for that,  Mr The Transporter

So I could use the original system if I had a mind to.
No reason why it shouldn't be flushed of mineral oil - it's in pieces at present.

The big question in my head at the moment is why do these systems loose refrigerant in the first place?
Porus pipework?
More likely the seal where the drive shaft enters the pump?
I'm thinking any system 30-40 years old probably needs all new seals fitting anyway.

[wildwood]

Seems they all lose after a few years....especially if not used..... Missus C max just got recharged after 3 years.....Tis well cold now. Not being used cos of the crap summer last year probably did not help

[dieselj20]

just change oil and recharge with 134a run pump once a month lubes pump seals

[bgbazz]

just change oil and recharge with 134a run pump once a month lubes pump seals

Many years ago a learned A/C dude advised me to run the aircon for 5 mins every month and I've followed that advice to the letter on every vehicle ever since...never had an issue. The day I bought my Patrol, six years ago, it was given a major service, including the aircon system...used it yesterday and it is still too cold on the max setting!! Seems like it was good advice.

How many of you know that the aircon, with the flow control set to 'demist' is the quickest way to clear the foggy windscreen?

[dieselj20]

70's fsj aircon doesn't blow on the screen just freezes the knees

[ferretjuggler]

So it's that very thin layer of oil/lubricant between the oil seal lip and the shaft that actually stops the gas from getting out.
Worth learning

[bgbazz]

So it's that very thin layer of oil/lubricant between the oil seal lip and the shaft that actually stops the gas from getting out.
Worth learning

That and keeping all the lines, hoses etc from drying out.

[bgbazz]

70's fsj aircon doesn't blow on the screen just freezes the knees

Wind the windows up and set the the system to 'recirc'. Even the 'Smiths' aircon I had in my 1964 EH Holden had that setting....just took a minute longer to demist the screen.

[ferretjuggler]

I think it's what they call a "stand alone" system.
The air conditioning isn't connected in any way to
 the heater and demister circuits.
So to clear the screen you gotta wait for the air conditioning to dry out the whole interior
Might be a long wait.

[bgbazz]

You are probably right about the system description and you'll get no argument from me. It always worked fine for me...feel free to use whatever method works for you. The Denso unit in my 7 seat Patrol is able to demist all nine windows (including windscreen) in about 3 minutes...and the screen is the only one with ducting. Worked fine from minus 30 all the way up 45C.

[ferretjuggler]

I don't think it would be rocket science to design and build an integrated heater demister air conditioning system for a J series using recycled bits from more modern vehicles.
TBH it's only the J series that I'm bothered about.
From my experience of driving the big black thing for a year and a half,  I never had any complaints about the power of the V8, the auto box, power steering or the brakes.
But the heating, wipers, and lighting were second rate.
I'm determined to sort this out for my second foray into FSJ driving.

[Dave69]

R12 uses bike pump values
R134 uses larger connections

oil needs to be flushed before refrigerant change
recommended change of O rings as these do degrade with age plus they will be of a different construction

Don't smoke while conducting a service as a hospital visit may happen

C02 was tried but the cost of pipework was proven to be not cost effective

yes the system loses charge over the years due to leaks through the rubber pipework

[The Transporter]

Thanks for that,  Mr The Transporter

So I could use the original system if I had a mind to.
No reason why it shouldn't be flushed of mineral oil - it's in pieces at present.

The big question in my head at the moment is why do these systems loose refrigerant in the first place?
Porus pipework?
More likely the seal where the drive shaft enters the pump?
I'm thinking any system 30-40 years old probably needs all new seals fitting anyway.

Yeah, should be no problem for you to be cool again... As the others said the refrigerant leaks past dry seals and stuff but I would guess that most pipe connections on your car are flair fittings rather than relying on horrid flexible seals but R134a can migrate through the flexible hoses and out of the compressor shaft seal.....

The aircon on my now 10 year old Transporter van was seitched on the day I bought it and hasn't been switched of yet and has never needed recharging but the compressor works in a slightly different way, with older systems it is better not to use when the clutch will cycle too often to prevent premature clutch wear, though if the clutch gap does become too large you can usually remove a shim to close it up again

[The Transporter]

Of course if you can find someone with a stash of R12......

[ferretjuggler]

Cheers
I've made some notes on this ( cos forum posts tend to get lost/ moved/ deleted)
More research due I think.
I'm wondering if building a system using bits off a modern vehicle might be less power sapping.
But then anything modern seems to have microchips stuffed into it somehow.
Then again.
If fuel consumption was my top priority I'd never have bought a FSJ in the first place

[The Transporter]

The only bit that is a bit out dated is the compressor.... A more modern but straight forward solution would be to use a Sanden SD7h15.... It is used on lots of stuff from tractors, plant, fridge vans and has loads of options for rear connections and pully fittings and is a one wire connection to operate the electromagnetic clutch..... 12 volts and the aircon runs, 0volts and it is off.... all the rest of the aircon stuff should be pretty standard stuff and available off the net...All you have to do is devise a bracket to locate the compressor and to allow you to tension it....I'd hazzard that they too are available off the net as the sanden was a popular replacement compressor

Just watch out when you buy one as some clutches are 24 volt for trucks rather than 12 volt..

[The Transporter]

FJ... Is your system an under dash unit? By that I mean you have a seperate aircon unit fastened to the lower part of the dash as an add on?