Two cars with no A/C: What tools do I need?

novaderrik wrote: my 97 Chevy truck has a slow leak in one of the charging ports that i thought i could fix by tightening down the valve, but there was no separate valve to tighten down. it appears to be integrated into the hose assembly when they weld it together..

The port should be replaceable. If it appears to have 8 flats on it, it can unscrew from the tube. I've replaced dozens over the years. Never did find a socket that fits well, I've always just mangulated it out with parrot-beak pliers and installed the new one with an open end wrench.

AC is overrated. (seriously, I never used it)

Knurled wrote:

novaderrik wrote: my 97 Chevy truck has a slow leak in one of the charging ports that i thought i could fix by tightening down the valve, but there was no separate valve to tighten down. it appears to be integrated into the hose assembly when they weld it together..

The port should be replaceable. If it appears to have 8 flats on it, it can unscrew from the tube. I've replaced dozens over the years. Never did find a socket that fits well, I've always just mangulated it out with parrot-beak pliers and installed the new one with an open end wrench.

yeah, it has flats but it won't turn. i thought it was supposed to come off, but i couldn't get it to budge and i wasn't gonna go crazy with a vise grips or anything and lose the ok working AC that i have..

mad_machine wrote: AC is overrated. (seriously, I never used it)

Try living someplace with 60+ days over 100F every summer.

I just got back from Harbor Freight with this:

http://www.harborfreight.com/air-vacuum-pump-with-r134a-and-r12-connectors-96677.html

and these:

http://www.harborfreight.com/a-c-manifold-gauge-set-92649.html

Now I just need to figure out how to use them.

In reply to Woody:

Woody, I tested that pump when I worked for Matco Tools. It wasn't capable of producing the pressure needed to boil water. Maybe they've improved it by now...

Manifold gauges and vacuum pump from HF. Test the clutch by giving it 12v. If that checks out, recover old freon, vacuum it down (through the manifold gauges) for a half hour. Close the valves and wait another half hour. If the needle moves back toward zero you have a leak. Replace o-rings, look for oil around the compressor pulley, etc. If not, go ahead and recharge it. I won't go into specifics since googles has a few million tutorials that are better than mine.

The basic electrical premise is that when you turn on the A/C inside, it sends 12v to a low pressure switch and a high pressure switch. If both of those switches are closed (within their parameters) it will continue the voltage to the compressor clutch. After your recharge, the switches should be closed and sending voltage to the clutch. If you're not getting engagement with proper charge pressure (and the clutch tested OK with 12v) then check for voltage at the switches and replace as necessary.

If you choose to flush, use A/C flush solvent. Don't use acetone or toluene or brake cleaner. A/C flush solvent is designed to evaporate at the vacuum pressures you use to evacuate the system. Other solvents may not evaporate and you'll have liquid solvent in the system.

Vacuum pump, I've never heard good things about those.

Manifold gauges; Pretty easy to use, the HI/LO valves connect the hi/lo lines to the manifold, generally speaking you keep HI valve shut and do all your charging, vacuum, etc. on the low side port.

So not that I want to thread jack, but this saves starting another thread. My 89 Delica came from Japan last year with the A/C inoperative. I have no idea what is wrong with it, and to be honest I have no idea how A/C even works. It seems like magic to me. If I wanted to get the system operational again, would I be best to just change it over to R13, or seek out a shop that has the capability to repair/recharge my R12 system? I assume the change over involves new fitting, and oil/seals? Any help on this is greatly appreciated as the van gets pretty warm with all that glass.

In reply to Mazdax605:

I'd swap it over to R134 if it was mine.

You might want to do some research to see if the compressor on it will be compatible.

I've had pretty good luck swapping old cars over just vacuuming them down and refilling them with R134, but the pros will tell you the world will end if you do that. The three I've done were older GM stuff from the 70s and 80s.

To do it right, I'd change the compressor, receiver/drier, orifice tube and flush both coils and all lines. Then add to proper amount of oil, vacuum for a hour or so and refill with the proper amount of refrigerant.

In reply to Woody:

I hope you have a large air compressor. Those vacuum pumps use a bunch of air.

The gauge set will definitely do the trick, that's the same one I've been using.

Nothing to it but to do it.

Big compressor: Check.

In reply to Woody:

Still won't pull enough to get the ~29.2" you need to boil water.

I read mixed reviews on it but figured I'd take a chance for $20.

mad_machine wrote: AC is overrated. (seriously, I never used it)

I mighta thought that until the last two years. I guess age is catching up.

I would return that vacuum pump and see if Autozone loans one out (an electric one).

Mazdax605 wrote: So not that I want to thread jack, but this saves starting another thread. My 89 Delica came from Japan last year with the A/C inoperative. I have no idea what is wrong with it, and to be honest I have no idea how A/C even works. It seems like magic to me. If I wanted to get the system operational again, would I be best to just change it over to R13, or seek out a shop that has the capability to repair/recharge my R12 system? I assume the change over involves new fitting, and oil/seals? Any help on this is greatly appreciated as the van gets pretty warm with all that glass.

A good way to start an argument on the internet is to ask what to do with a broken R12 system.

Opinions range anywhere from "fill it with 134a and see how long it lasts" to "replace somewhere between most of and the whole system and charge with 134a and PAG oil" to "Keep using 12 or a 12 substitute and mineral oil". I generally sit in the 12 or a substitute camp. Most are hydrocarbon based, which freaks some people out, though really any AC system runs a risk of fireball in a crash (oil mist). Putting 134a in them is a real crapshoot, the design characteristics of a 134a system are somewhat different from a R-12 system, some work great on it, some ok, some terribly. IIRC 134a runs at higher pressure as well.

AC work really isn't that difficult (it's not magic) and the tools quickly pay for themselves, the consumables for R-12 systems (including real R-12 if you look around for it) are still readily available as there are many commercial/industrial R-12 (or related) systems still in service.

You'll need to find where the old charge leaked out and go from there. Look along the lines, compressor, etc. especially any joints, for signs of an oil leak. If you can't find anything to fix, put a wrench on all the connections and see if one vibrated loose. Then pull a vacuum on it, charge it with a 12 substitute, maybe a little (1/2oz or so) of the appropriate oil(to account for any leakage), and a shot of dye, see what turns green. A new dryer and the appropriate amount of oil (see FSM) is never a bad idea either.

In reply to Kenny_McCormic:

A little more thread jack.

Have you used the replacement R12 on anything? My truck is still R12 and works fine. If the replacement works just as well, I might not convert it.

I've got a shop system running on R290, so hydrocarbons don't worry me too much.

bravenrace wrote: In reply to Woody: Woody, I tested that pump when I worked for Matco Tools. It wasn't capable of producing the pressure needed to boil water. Maybe they've improved it by now...

This is another great example of why you would want to heat up the system while pulling a vacuum (if you're worried about water). Water boils at 212F at ambient pressure. It boils at 70F if you pull 29.2" Hg of vacuum. If you can't pull a great vacuum, the boiling temp is likely to be just above ambient temp, so heat it up and you're all set.

On the R12 to R134a debate, I'm not an expert, and it could vary a lot from system to system, but have had my Celica running on R134a (originally R12) for 5 years. I didn't change anything in the system and have had zero problems. This is usually my daily driver and I'm in Atlanta, so the system has a lot of hours running like that.

In reply to Toyman01:

The only R-12 car I ever had kinda blew up on me before I got around to fixing the AC, but I've read a lot about the HC based subs in preparation to fix it, you don't hear much in the way of bad things. The science is sound. Should work better if anything changes, as I recall.

I've decided that I'm not even going to mess with this thing.

It's going back in the morning and I'm going to pick up one of these.

http://www.harborfreight.com/25-cfm-vacuum-pump-98076.html

Toyman01 wrote: I've had pretty good luck swapping old cars over just vacuuming them down and refilling them with R134, but the pros will tell you the world will end if you do that. The three I've done were older GM stuff from the 70s and 80s.

That's exactly what I did (using a conversion kit from id) on my `92 Custom Cruiser about two weeks ago. It still works, so I am cautiously optimistic I'll make it the entire summer.

On the R12 conversion, it could be simple or could be more involved. The main basic difference is that R12 requires a greater pressure variance to evaporate efficiently. If the factory R12 system has adequate adiabatic qualities to effectively evaporate the refrigerant, it should operate at about 75% its original efficiency with R134. I had an employee who did this in a 1984 chevy pickup. He just bought the adapter valves for the ports and filled it with R134. It got cool but not cold. Fortunately it was a small cab.

The main things to address are an adequately evaporative orifice tube (get creative and find a way to adapt in a newer hose with one of them in it) and adequate condensing. (bigger or more efficent condenser with a fan)

In reply to Woody:

That's the pump I have and it works like a charm.

I am a moron. Here's why:

This morning, I went out to the garage with my new pump and new gauges. Before getting started, I decided to do a visual confirmation that the compressor clutch was engaging.

Last week when I realized that I wasn't getting any cool air, I noticed that the engine speed wasn't changing when I pushed the AC button. I checked the fuses (good) and then thought that the system might not have enough pressure in it to trip the pressure switch. I added a can of refrigerant, and sure enough when I pushed the AC button, the engine speed went up a few hundred RPM and I could hear the second fan kick on. I never checked to see if the clutch was actually engaging. It is not. So now I need to figure out why.

D'oh.