Replacement of A/C Compressor, R12 to R134a
11-19-2014, 03:41 PM
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Replacement of A/C Compressor, R12 to R134a
It’s a little late in the season to post this, but I’m a victim of sloth.
During a 2,000 mile trip this summer, my A/C slowly became more and more anemic. On my return, an inspection underneath the truck showed a quantity of odd-smelling grease on the bottom of the compressor, which lead me to believe it had failed, leaking out the magic goo.
A/C has always seemed like Black Magic to me. To an even greater extent than many other endeavors, the Internet repeatedly advises “leave it to the experts.” But, here goes.
First, I was confident I needed a replacement compressor. I’m guessing that when a compressor gives up, it often shoots trash through the rest of the system As a result, each compressor offered for sale ominously warned “There is NO warrantee on this compressor unless you can prove you both replaced the Expansion Valve and Flushed the system!” Whew! So I bought the set that included the compressor and the Thermal Expansion Valve (TXV) and a complete set of green o-rings. With the conversion fittings (R12 to R134a) and the dryer/receiver (“you always replace the dryer when you recharge the system”) just over $200 delivered.
R12 ports
Ports with conversion adaptors
Ports with manifold gauge connected
What of the “stuff” that’s still in the system? After some research on some kinds of “Air Conditioner in a can” products, I determined I needed a Manifold gauge. The internet produced one for $29, but it had only the R12 fittings, and not the adaptors for the newer R134a fittings. The HF unit http://www.harborfreight.com/a-c-man...set-92649.html for $50 had everything I needed, AND a nice case. (While I was at HF, I picked up the vacuum pump I knew I was going to need. http://www.harborfreight.com/25-cfm-...ump-61245.html). Using the manifold gauge, I determined I had zero pressure on both sides (high/low) of the system. This was good; if I still had any refrigerant in the system I would need to take it to a shop to have it “recovered.” There’s no decent home-shop way to recover Freon, and I wasn’t about to let it out into the atmosphere.
What to put back in? R12 has been illegal for new vehicles since January 1, 1994. My ‘94 was built in August 1993, and it appears that Toyota took the full count and continued to use R12 right up to the end of the year. (How do I know? There’s a sticker giving the charge amount of R12, and the fittings are R12 fittings.) If you have the right license (which I don’t), you can get R12, but it’s insanely expensive. And moving backwards. There are alternative “environmentally safe” refrigerants like http://www.es-refrigerants.com/produ...-kit&Trying=ON , which appear to be mostly propane. Supposedly, you can safely mix these with old R12 or R134a.. But the alternatives are a) flammable, and b) NOT approved by the EPA. In other words, probably illegal to use when replacing all the refrigerant, as I had to do.
So I decided to go with “modern” (well, at least for another few years) R134a. How much? Incredibly, thanks to YotaTech I found a 1998 Service Bulletin on this very subject. http://tms.ccar-greenlink.org/NewsLetter/ac002t98.pdf 700grams is the spec. “Old school” R134a comes in cans you open by piercing the top with a “can tap.” I would need 2 cans PLUS a little more. Because (I guess) people just pull the tap out of the last can and let it swoosh out into the air, it is getting harder and harder to get cans of R134a without a built-in valve, which runs up the price. Fortunately, the internet hasn’t heard of that, and I was able to get three cans for $18.50 delivered.
What else? The compressor has to be oiled. In the R12 days, you just used “mineral oil” (basically, unscented Baby Oil). I had once heard that the new refrigerant would attack the old o-rings, and new o-rings that tolerated R134a needed a compatible oil! Supposedly, “Ester” Oil is a sort of univeral oil that can be mixed with anything. Sheesh!
Today, you use polyalkylene glycol (PAG) oil. It took a little bit of looking, but it turns out the “ND Oil-8" specified in the Toyota TSB is PAG 45 (45 is a viscosity measure). And the TSB gives the amount: 100cc. If PAG 45 is in the TSB, it’s good enough for me. Just for fun, I purchased the PAG 45 with UV dye added, to highlight leaks. You can buy the UV dye separately, or you can get it mixed with refrigerant, too.
Because I was replacing the TXV, I was going to have to pull the Cooling Unit under the glove box. I was going to end up disconnecting every fitting, and replacing every o-ring. Since the compressor was being replaced, I didn’t have to worry about old oil in the compressor (You can’t flush a compressor, or a TXV.) So I didn’t have to worry about compatibility; everything would be new!
It looks like it might be possible to remove the compressor by going down, but I would have to remove the transmission cooler lines to do that. And it sure didn’t look easy to access the refrigerant lines on the top of the compressor. So I decided to go up, and that meant removing the cowl, fan, battery, and power steering pump (if someone knows how to remove the PS pump without getting ATF all over the place, I’d sure like to hear it). I was replacing the dryer, and the evaporator came out to access the TXV, so the only thing left was the condensor and one HP line. Since I planned to flush everything, and it’s much easier if you can hold the “low” end over a bucket, out came the condensor and all the lines. (The HP line from the front of the truck to the evaporator runs under the bracket holding a set of VSVs. That bracket had to be loosened to access the tube clamps. To remove the condensor you have to remove the grill and the hood latch. To get to the refrigerant fittings up by the cooling unit, I needed to remove the Evap canister.)
“A/C System Flush” is a cross between paint thinner and brake cleaner; a good solvent that dries fast, but not so fast it can’t drain out with the crud. Autozone has a loaner tool for that; an “aerosol” can with a schrader valve on top and a air-line connector on the bottom. Oddly, the schraeder valve is unthreaded; you can’t plumb it into compressed air with a regular fitting, and my tire-chuck couldn’t grip the smooth sides unless held by hand. But just pumping the can up to about 40psi was enough; you’re just pushing fluid out the bottom and through each of the components and lines.
A/C Flush tool
I was lucky (I guess); the fluid that came out of each component was pretty clean! (So clean that I saved all the “used” Flush to use in the future to clean greasy parts). Each component was scavenged with compressed air, and then sat in the sun for a half-hour to dry out. I used plain-old masking tape to keep moisture out of the cleaned components; if the humidity were higher that might not have been enough.
The coils of the evaporator were a little dusty, and clearly benefitted from vacuuming. Others (who probably park under leafy trees) have much more crud in the cooling unit; if you’re replacing your refrigerant it is definitely worth pulling the evaporator while you can.
Evaporator half-way out of cooling unit; a little dirty.
The TSB calls for ½ of the PAG Oil to be put into the drier, with the rest in the compressor. I had a little trouble getting 50cc into the drier, but it turned out not to be necessary! To my surprise, the fine print on a piece of tape on the compressor announced that it was already filled with the proper amount of oil. (you have to use the old extension housing on the new compressor; it comes with a flat metal plate that seals the new oil inside). I put the PAG oil to good use; every one of the new o-rings was carefully dipped in a little oil before installation (I used nitrile gloves; I don’t know if PAG will hurt you, but I don’t want to be the one to find out.)
Old and New Compressor; you only need to clean the extension housing
There is a torque spec on every connection; how do you fit a torque wrench on such a fitting? I had the correct size crows-foot wrench; if you turn the wrench so the crows foot “points” 90 degrees from the wrench, you don’t have to correct for offset. Even better would be to use flare-nut crows-foot wrenches. Fortunately, every connection is an o-ring connection, so the nut only has to be tight enough to survive vibration (the fittings are aluminum, so don’t go too tight).
I now had everything assembled EXCEPT for the R134a conversion fittings (they were shipped from a different source and got lost). But is it pressure-tight? I could vacuum test the system even with the wrong fittings, because the manifold gauge had both R12 fittings and the R134a adaptors. So I hooked up the vacuum pump, it immediately pulled a vacuum, and with the pump off it held vacuum. Whoo-hoo! But wait — what if the gauge isn’t hooked up right? What if the schrader valves didn’t open, and all I’m measuring is the vacuum inside the manifold? (Since I didn’t have pressure at all when I first measured, who knows if it was hooked up at all?) So I carefully removed the gauge, assured that the vacuum inside the manifold was released, and hooked the gauge up again. When I opened the connector, the gauge showed vacuum, proving it was now connected, and that the connections were all vacuum-tight.
A few days later my last conversion adaptor showed up. There are three kinds of adaptors (I learned): the most common (and the ones I had) have their own schrader valve, and you need to remove the existing “R12" schrader core. Fortunately, they take the same tool as the schrader valve on a tire, and I had that tool. (What this means is that you can’t, for instance, fill the refrigerant and then put the adaptors on later.) With the adaptors on, I hooked up the vacuum pump and let it run for an hour. An hour? The gauge shows a really good vacuum in less than 5 minutes, and doesn’t change. The reason you “run” the vacuum for so long is to remove any water in the system. The water won’t boil (at common temperatures) with the vacuum you can pull, but it will “dry” quickly as the vapor pressure is close to the system pressure. So it takes a while for all the water to mosey out of the system, and you need to keep pumping the vacuum during that time.
Core of R12 valve, and tool used to remove it.
Now to add the right amount of refrigerant! I knew I needed two cans plus 20 (or so) grams. I have a gram scale, but since the can is connected to a hose, it’s difficult to get accurate weight. So I weighed an unopened can and the can-tap separately. Once I got to where I thought I was close, I would disconnect the hose and weigh you can with tap attached.
Scale, R134a can, can-tap
Because you are pushing refrigerant in against pressure, you run the engine at about 1500 rpm, and add the refrigerant (through the manifold gauge) to the low side. The low side is still about 50 psi, so you won’t be able to empty the can, but you can get close. What surprised me is that the pressure in the can is (of course) temperature dependent. And as the refrigerant leaves the can, the can gets colder, lowering the pressure in the can! At first I just tried shaking the can and waiting, but I eventually realized I was just using my hand and ambient air to warm the can. At the end, I got a small plastic tub filled with hot water to warm the can – that made it empty promptly!
Once I was about 20 percent through the third can, I shut the tap. I disconnected the hose, and weighed the can and tap. I was careful charging by weight, but it’s hard to compensate for the amount left in the hoses. Did I have enough refrigerant? Too much? The parts-store “air-conditioning” in a can use a crude gauge right on the can, supposedly measuring the pressure on the low side. Even Eric-The-Car-Guy says this method is totally inaccurate
, and since he uses a lot of short-cuts himself I believed he was right.
But it turns out the “right way” isn’t that difficult, if you have a reasonable way to measure both pressure (the manifold gauge) and temperature. I have a few thermocouple gauges, but the one that read closest to my best thermometer came from, you guessed it, http://www.harborfreight.com/5-in-1-...ter-98674.html . Notice that the high-pressure gauge has a dial marked “R134a” and reads in degrees F. That’s the boiling point of R134a at that pressure. (Or you can use this chart: http://emea.forane.com/export/shared...ture-chart.pdf ) This youtube explanation isn’t too bad:
High-side gauge, showing R134a scale (degrees F)
The high-side pressure is almost constant from the output of the compressor up to the TXV. So your high side reading (taken right at the entrance to the cooling unit) is only about 12psi lower than the pressure at the exit from the condensor in front. But not the temperature; so you measure the temperature by placing the thermocouple right on the refrigerant tube there. You expect that, whatever the pressure, the condensor “condensed” all the refrigerant into liquid at that point. So you expect the temperature to be LOWER than the boiling point for that pressure.
The low-side is measured right at the exit from the cooling unit, where you expect that all of the refrigerant has given up its “cold” by evaporating in the evaporator. So you expect a temperature that is ABOVE the boiling point at that pressure.
Too complicated? Well, for my first time, I wanted someone to hold my hand. So I used this set of instructions: http://www.4s.com/Upload/Four%20Seas...arge_Level.pdf Even better, you just need to fill in the blanks in this form: http://www.4s.com/Upload/Four%20Seas...Worksheets.pdf, and you should be good to go!
But does it leak? I checked the whole system under vacuum, and it would hold vacuum (without the pump running) overnight. But what about when it’s under hundreds of psi pressure? That’s where the UV-dyed PAG 45 comes in. I have an inexpensive UV LED flashlight like (UV LEDs emit a fair amount of visible light, so it’s not always clear that you’re seeing fluorescence. UV fluorescent bulbs, like that one hanging over your Pink Floyd poster, are closer to “black-light” and do work better if you have one). But there’s a catch; even though I tried to be careful when I dipped each o-ring in oil, I ended up with some UV dye on the outside of each connection. But it’s just oil; squirt a little 409 on each connection and spray with water. Be extra careful checking the compressor for leaks; you’re looking past the fan, which you can’t see when it’s running.
My truck is now cold enough inside the cab to store sides of beef!
Remember: this was my very first time working with A/C. If you see where I screwed up, by all means help out those who may follow and set me straight. A link to a clear resource is even better.
My advice: if you have a pre-1/1/1994 (R12) A/C system that isn’t working, don’t try to do things half-way. Pay someone to recover the R12. Then just pull it apart, flush if you see any discolored oil come out, replace all the o-rings, and charge it up with R134a. Then you’ll be done with it!
During a 2,000 mile trip this summer, my A/C slowly became more and more anemic. On my return, an inspection underneath the truck showed a quantity of odd-smelling grease on the bottom of the compressor, which lead me to believe it had failed, leaking out the magic goo.
A/C has always seemed like Black Magic to me. To an even greater extent than many other endeavors, the Internet repeatedly advises “leave it to the experts.” But, here goes.
First, I was confident I needed a replacement compressor. I’m guessing that when a compressor gives up, it often shoots trash through the rest of the system As a result, each compressor offered for sale ominously warned “There is NO warrantee on this compressor unless you can prove you both replaced the Expansion Valve and Flushed the system!” Whew! So I bought the set that included the compressor and the Thermal Expansion Valve (TXV) and a complete set of green o-rings. With the conversion fittings (R12 to R134a) and the dryer/receiver (“you always replace the dryer when you recharge the system”) just over $200 delivered.
R12 ports
Ports with conversion adaptors
Ports with manifold gauge connected
What of the “stuff” that’s still in the system? After some research on some kinds of “Air Conditioner in a can” products, I determined I needed a Manifold gauge. The internet produced one for $29, but it had only the R12 fittings, and not the adaptors for the newer R134a fittings. The HF unit http://www.harborfreight.com/a-c-man...set-92649.html for $50 had everything I needed, AND a nice case. (While I was at HF, I picked up the vacuum pump I knew I was going to need. http://www.harborfreight.com/25-cfm-...ump-61245.html). Using the manifold gauge, I determined I had zero pressure on both sides (high/low) of the system. This was good; if I still had any refrigerant in the system I would need to take it to a shop to have it “recovered.” There’s no decent home-shop way to recover Freon, and I wasn’t about to let it out into the atmosphere.
What to put back in? R12 has been illegal for new vehicles since January 1, 1994. My ‘94 was built in August 1993, and it appears that Toyota took the full count and continued to use R12 right up to the end of the year. (How do I know? There’s a sticker giving the charge amount of R12, and the fittings are R12 fittings.) If you have the right license (which I don’t), you can get R12, but it’s insanely expensive. And moving backwards. There are alternative “environmentally safe” refrigerants like http://www.es-refrigerants.com/produ...-kit&Trying=ON , which appear to be mostly propane. Supposedly, you can safely mix these with old R12 or R134a.. But the alternatives are a) flammable, and b) NOT approved by the EPA. In other words, probably illegal to use when replacing all the refrigerant, as I had to do.
So I decided to go with “modern” (well, at least for another few years) R134a. How much? Incredibly, thanks to YotaTech I found a 1998 Service Bulletin on this very subject. http://tms.ccar-greenlink.org/NewsLetter/ac002t98.pdf 700grams is the spec. “Old school” R134a comes in cans you open by piercing the top with a “can tap.” I would need 2 cans PLUS a little more. Because (I guess) people just pull the tap out of the last can and let it swoosh out into the air, it is getting harder and harder to get cans of R134a without a built-in valve, which runs up the price. Fortunately, the internet hasn’t heard of that, and I was able to get three cans for $18.50 delivered.
What else? The compressor has to be oiled. In the R12 days, you just used “mineral oil” (basically, unscented Baby Oil). I had once heard that the new refrigerant would attack the old o-rings, and new o-rings that tolerated R134a needed a compatible oil! Supposedly, “Ester” Oil is a sort of univeral oil that can be mixed with anything. Sheesh!
Today, you use polyalkylene glycol (PAG) oil. It took a little bit of looking, but it turns out the “ND Oil-8" specified in the Toyota TSB is PAG 45 (45 is a viscosity measure). And the TSB gives the amount: 100cc. If PAG 45 is in the TSB, it’s good enough for me. Just for fun, I purchased the PAG 45 with UV dye added, to highlight leaks. You can buy the UV dye separately, or you can get it mixed with refrigerant, too.
Because I was replacing the TXV, I was going to have to pull the Cooling Unit under the glove box. I was going to end up disconnecting every fitting, and replacing every o-ring. Since the compressor was being replaced, I didn’t have to worry about old oil in the compressor (You can’t flush a compressor, or a TXV.) So I didn’t have to worry about compatibility; everything would be new!
It looks like it might be possible to remove the compressor by going down, but I would have to remove the transmission cooler lines to do that. And it sure didn’t look easy to access the refrigerant lines on the top of the compressor. So I decided to go up, and that meant removing the cowl, fan, battery, and power steering pump (if someone knows how to remove the PS pump without getting ATF all over the place, I’d sure like to hear it). I was replacing the dryer, and the evaporator came out to access the TXV, so the only thing left was the condensor and one HP line. Since I planned to flush everything, and it’s much easier if you can hold the “low” end over a bucket, out came the condensor and all the lines. (The HP line from the front of the truck to the evaporator runs under the bracket holding a set of VSVs. That bracket had to be loosened to access the tube clamps. To remove the condensor you have to remove the grill and the hood latch. To get to the refrigerant fittings up by the cooling unit, I needed to remove the Evap canister.)
“A/C System Flush” is a cross between paint thinner and brake cleaner; a good solvent that dries fast, but not so fast it can’t drain out with the crud. Autozone has a loaner tool for that; an “aerosol” can with a schrader valve on top and a air-line connector on the bottom. Oddly, the schraeder valve is unthreaded; you can’t plumb it into compressed air with a regular fitting, and my tire-chuck couldn’t grip the smooth sides unless held by hand. But just pumping the can up to about 40psi was enough; you’re just pushing fluid out the bottom and through each of the components and lines.
A/C Flush tool
I was lucky (I guess); the fluid that came out of each component was pretty clean! (So clean that I saved all the “used” Flush to use in the future to clean greasy parts). Each component was scavenged with compressed air, and then sat in the sun for a half-hour to dry out. I used plain-old masking tape to keep moisture out of the cleaned components; if the humidity were higher that might not have been enough.
The coils of the evaporator were a little dusty, and clearly benefitted from vacuuming. Others (who probably park under leafy trees) have much more crud in the cooling unit; if you’re replacing your refrigerant it is definitely worth pulling the evaporator while you can.
Evaporator half-way out of cooling unit; a little dirty.
The TSB calls for ½ of the PAG Oil to be put into the drier, with the rest in the compressor. I had a little trouble getting 50cc into the drier, but it turned out not to be necessary! To my surprise, the fine print on a piece of tape on the compressor announced that it was already filled with the proper amount of oil. (you have to use the old extension housing on the new compressor; it comes with a flat metal plate that seals the new oil inside). I put the PAG oil to good use; every one of the new o-rings was carefully dipped in a little oil before installation (I used nitrile gloves; I don’t know if PAG will hurt you, but I don’t want to be the one to find out.)
Old and New Compressor; you only need to clean the extension housing
There is a torque spec on every connection; how do you fit a torque wrench on such a fitting? I had the correct size crows-foot wrench; if you turn the wrench so the crows foot “points” 90 degrees from the wrench, you don’t have to correct for offset. Even better would be to use flare-nut crows-foot wrenches. Fortunately, every connection is an o-ring connection, so the nut only has to be tight enough to survive vibration (the fittings are aluminum, so don’t go too tight).
I now had everything assembled EXCEPT for the R134a conversion fittings (they were shipped from a different source and got lost). But is it pressure-tight? I could vacuum test the system even with the wrong fittings, because the manifold gauge had both R12 fittings and the R134a adaptors. So I hooked up the vacuum pump, it immediately pulled a vacuum, and with the pump off it held vacuum. Whoo-hoo! But wait — what if the gauge isn’t hooked up right? What if the schrader valves didn’t open, and all I’m measuring is the vacuum inside the manifold? (Since I didn’t have pressure at all when I first measured, who knows if it was hooked up at all?) So I carefully removed the gauge, assured that the vacuum inside the manifold was released, and hooked the gauge up again. When I opened the connector, the gauge showed vacuum, proving it was now connected, and that the connections were all vacuum-tight.
A few days later my last conversion adaptor showed up. There are three kinds of adaptors (I learned): the most common (and the ones I had) have their own schrader valve, and you need to remove the existing “R12" schrader core. Fortunately, they take the same tool as the schrader valve on a tire, and I had that tool. (What this means is that you can’t, for instance, fill the refrigerant and then put the adaptors on later.) With the adaptors on, I hooked up the vacuum pump and let it run for an hour. An hour? The gauge shows a really good vacuum in less than 5 minutes, and doesn’t change. The reason you “run” the vacuum for so long is to remove any water in the system. The water won’t boil (at common temperatures) with the vacuum you can pull, but it will “dry” quickly as the vapor pressure is close to the system pressure. So it takes a while for all the water to mosey out of the system, and you need to keep pumping the vacuum during that time.
Core of R12 valve, and tool used to remove it.
Now to add the right amount of refrigerant! I knew I needed two cans plus 20 (or so) grams. I have a gram scale, but since the can is connected to a hose, it’s difficult to get accurate weight. So I weighed an unopened can and the can-tap separately. Once I got to where I thought I was close, I would disconnect the hose and weigh you can with tap attached.
Scale, R134a can, can-tap
Because you are pushing refrigerant in against pressure, you run the engine at about 1500 rpm, and add the refrigerant (through the manifold gauge) to the low side. The low side is still about 50 psi, so you won’t be able to empty the can, but you can get close. What surprised me is that the pressure in the can is (of course) temperature dependent. And as the refrigerant leaves the can, the can gets colder, lowering the pressure in the can! At first I just tried shaking the can and waiting, but I eventually realized I was just using my hand and ambient air to warm the can. At the end, I got a small plastic tub filled with hot water to warm the can – that made it empty promptly!
Once I was about 20 percent through the third can, I shut the tap. I disconnected the hose, and weighed the can and tap. I was careful charging by weight, but it’s hard to compensate for the amount left in the hoses. Did I have enough refrigerant? Too much? The parts-store “air-conditioning” in a can use a crude gauge right on the can, supposedly measuring the pressure on the low side. Even Eric-The-Car-Guy says this method is totally inaccurate
But it turns out the “right way” isn’t that difficult, if you have a reasonable way to measure both pressure (the manifold gauge) and temperature. I have a few thermocouple gauges, but the one that read closest to my best thermometer came from, you guessed it, http://www.harborfreight.com/5-in-1-...ter-98674.html . Notice that the high-pressure gauge has a dial marked “R134a” and reads in degrees F. That’s the boiling point of R134a at that pressure. (Or you can use this chart: http://emea.forane.com/export/shared...ture-chart.pdf ) This youtube explanation isn’t too bad:
High-side gauge, showing R134a scale (degrees F)
The high-side pressure is almost constant from the output of the compressor up to the TXV. So your high side reading (taken right at the entrance to the cooling unit) is only about 12psi lower than the pressure at the exit from the condensor in front. But not the temperature; so you measure the temperature by placing the thermocouple right on the refrigerant tube there. You expect that, whatever the pressure, the condensor “condensed” all the refrigerant into liquid at that point. So you expect the temperature to be LOWER than the boiling point for that pressure.
The low-side is measured right at the exit from the cooling unit, where you expect that all of the refrigerant has given up its “cold” by evaporating in the evaporator. So you expect a temperature that is ABOVE the boiling point at that pressure.
Too complicated? Well, for my first time, I wanted someone to hold my hand. So I used this set of instructions: http://www.4s.com/Upload/Four%20Seas...arge_Level.pdf Even better, you just need to fill in the blanks in this form: http://www.4s.com/Upload/Four%20Seas...Worksheets.pdf, and you should be good to go!
But does it leak? I checked the whole system under vacuum, and it would hold vacuum (without the pump running) overnight. But what about when it’s under hundreds of psi pressure? That’s where the UV-dyed PAG 45 comes in. I have an inexpensive UV LED flashlight like (UV LEDs emit a fair amount of visible light, so it’s not always clear that you’re seeing fluorescence. UV fluorescent bulbs, like that one hanging over your Pink Floyd poster, are closer to “black-light” and do work better if you have one). But there’s a catch; even though I tried to be careful when I dipped each o-ring in oil, I ended up with some UV dye on the outside of each connection. But it’s just oil; squirt a little 409 on each connection and spray with water. Be extra careful checking the compressor for leaks; you’re looking past the fan, which you can’t see when it’s running.
My truck is now cold enough inside the cab to store sides of beef!
Remember: this was my very first time working with A/C. If you see where I screwed up, by all means help out those who may follow and set me straight. A link to a clear resource is even better.
My advice: if you have a pre-1/1/1994 (R12) A/C system that isn’t working, don’t try to do things half-way. Pay someone to recover the R12. Then just pull it apart, flush if you see any discolored oil come out, replace all the o-rings, and charge it up with R134a. Then you’ll be done with it!
Last edited by scope103; 11-20-2014 at 06:48 AM.
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11-21-2014, 06:54 AM
#6
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They're a professional hand-model's. ;^)
Use nitrile gloves. Tough enough that I even take them off and re-use them 3-4 times (but cheap enough that you don't need to). Resistant to gasoline, which latex gloves are not.
Use nitrile gloves. Tough enough that I even take them off and re-use them 3-4 times (but cheap enough that you don't need to). Resistant to gasoline, which latex gloves are not.
11-21-2014, 10:12 AM
#7
I've used those before when working with PL glue. That stuff takes a week to get off of skin 
A few people in my life told me I should be a hand/upper arm model, but I never checked it out. I always thought my piano fingers were a bit too long. Probably too late for me now anyway after all the cuts scrapes and burns. Supposedly pays pretty well though, right?
Also your engine bay looks spotless. I'm impressed
A few people in my life told me I should be a hand/upper arm model, but I never checked it out. I always thought my piano fingers were a bit too long. Probably too late for me now anyway after all the cuts scrapes and burns. Supposedly pays pretty well though, right?
Also your engine bay looks spotless. I'm impressed
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11-21-2014, 02:38 PM
#9
Ooh good idea
Scope I'm coming up there! I know how much y'all bay people love grimey-butt LA!
Also I would love to do this mod in time for next summer. My AC was cold when I got the car in Aug/Sept (I'm assuming PO recharged it), but it is already at about 30% what it was.
Scope I'm coming up there! I know how much y'all bay people love grimey-butt LA!
Also I would love to do this mod in time for next summer. My AC was cold when I got the car in Aug/Sept (I'm assuming PO recharged it), but it is already at about 30% what it was.
06-17-2017, 06:26 PM
#10
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I know it is kind of old, but I saw this very good writeup and had a couple of questions.
My 93 is in the same boat and I'm now confident that the compressor has a leak. A shop wanted something ridiculous like $900 to replace compressor and refill, but I know that a few hundred of that was R12. So...
1. Where is the best place to buy a compressor? Rebuilt or aftermarket? I'm always a little skeptical about aftermarket stuff doing the job, but this is an old truck and I want to keep costs down.
2. When you buy a compressor, does it have to be a R134a compressor? Can a rebuilt R12 compressor do the job just as well?
Would appreciate any other helpful info. Great writeup by the way!
My 93 is in the same boat and I'm now confident that the compressor has a leak. A shop wanted something ridiculous like $900 to replace compressor and refill, but I know that a few hundred of that was R12. So...
1. Where is the best place to buy a compressor? Rebuilt or aftermarket? I'm always a little skeptical about aftermarket stuff doing the job, but this is an old truck and I want to keep costs down.
2. When you buy a compressor, does it have to be a R134a compressor? Can a rebuilt R12 compressor do the job just as well?
Would appreciate any other helpful info. Great writeup by the way!
06-17-2017, 06:58 PM
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I got a GPD Compressor (in a kit, with the receiver/dryer, TXV, and seals) from RockAuto. I later learned that I could have gotten a rebuild kit (big orings and the like) for the compressor, but at $205 for the kit I'm happy I went that way. Mine was new, not rebuilt. As far as after-market goes, 1) Toyota doesn't build compressors. So your 24-yr old compressor is "aftermarket" to someone. 2) Your current compressor lasted for 24 years. Are you afraid that a non-"Toyota" compressor will only last for 18? 12?
I don't think there is any difference between R12 and R134a compressors (at least as far as what you an put into your truck is concerned. Maybe newer compressors are designed differently, but you can't take advantage of that.)
But as I said in my writeup, I think putting R12 back in is going backwards (at best). When you replace the compressor, you're going to have to replace the TXV and flush the system (or else there is no warrantee). You have to remove the Evaporator box to get to the TXV (and it's a great opportunity to clean all the leaves out!), so once you've gone that far it's trivial to just remove the rest of the components. Then you're going to replace all the o-rings, and add all new "oil," so there is absolutely no purpose to putting R12 back in.
Can you just cheap out, squeeze in a rebuilt compressor, and try to get a couple-hundred dollars of R12 so you can avoid replacing the TXV, o-rings, and "oil"? Uh, why? No shop will warrantee the R12 fill if they can't leak-test it, so you could end up back where you started. Just upgrade to R134a and be done with it.
Last, if you figure the $900 you were quoted is "ridiculous," add up the cost of the compressor, other parts, and R12. Factor in the time you think it will take you to do it yourself. I probably ended up paying myself about $12/hour. I did it because I liked the challenge, not to save money.
I don't think there is any difference between R12 and R134a compressors (at least as far as what you an put into your truck is concerned. Maybe newer compressors are designed differently, but you can't take advantage of that.)
But as I said in my writeup, I think putting R12 back in is going backwards (at best). When you replace the compressor, you're going to have to replace the TXV and flush the system (or else there is no warrantee). You have to remove the Evaporator box to get to the TXV (and it's a great opportunity to clean all the leaves out!), so once you've gone that far it's trivial to just remove the rest of the components. Then you're going to replace all the o-rings, and add all new "oil," so there is absolutely no purpose to putting R12 back in.
Can you just cheap out, squeeze in a rebuilt compressor, and try to get a couple-hundred dollars of R12 so you can avoid replacing the TXV, o-rings, and "oil"? Uh, why? No shop will warrantee the R12 fill if they can't leak-test it, so you could end up back where you started. Just upgrade to R134a and be done with it.
Last, if you figure the $900 you were quoted is "ridiculous," add up the cost of the compressor, other parts, and R12. Factor in the time you think it will take you to do it yourself. I probably ended up paying myself about $12/hour. I did it because I liked the challenge, not to save money.
06-17-2017, 07:36 PM
#13
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great write up
I did a similar thing last summer
Its STILL holding and blowing cold
Hell - its holding better than the R12 recharge I had a shop do circa 1997!
(and I cut all kinds of corners on mine - I now have all the parts to do it proper, but its holding and blowing cold, so Im not gonna mess with it)
BTW - the later model AC lines are FAR EASIER to get to. My ports are on the compressor. TIGHT access!
I did a similar thing last summer
Its STILL holding and blowing cold
Hell - its holding better than the R12 recharge I had a shop do circa 1997!
(and I cut all kinds of corners on mine - I now have all the parts to do it proper, but its holding and blowing cold, so Im not gonna mess with it)
BTW - the later model AC lines are FAR EASIER to get to. My ports are on the compressor. TIGHT access!
06-18-2017, 08:43 PM
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The "green" orings are at every other connection; two on the compressor, two on the condenser, two on the dryer, TXV, and evaporator. (I think there are even orings in the R134a adaptor fittings.)
There's also a funny rectangular one for the extension housing.
But you don't worry about count; the oring "sets" are as common as dirt.
06-19-2017, 03:51 AM
#18
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Fantastic write up! I'll be using this in the future. Thank you!
07-27-2017, 09:17 AM
#19
Nice write up. I am going through all of this right now and it has been a long haul, but I have learned a lot.
I bought all new everything. The only parts that will not be replaced are the lines in the front from the condenser to the drier.
My big question is oil. My denso compressor is pre-filled, like yours. But that's all you did? I have read other threads that say that I need to add oil to each component. Specifically 10cc's (0.34oz) to the drier. Condenser 40cc's (1.4oz). Evaporator 40cc's(1.4oz). And compressor 140cc's (4.9oz). I am leaning towards believing them because how do the manufacturers who made your compressor know that you are changing the oil in the other components as well? I'm thinking they just send the compressor with what that one part requires for oil.
Last question is the fittings. I have the new R134a adapters and removed the schrader valve from one of the R12 fittings. The other adapter fitting does not have a valve in it and sits much closer to the R12 valve. Do I just leave that one alone?
Again great write up. I appreciate the time and help!
I bought all new everything. The only parts that will not be replaced are the lines in the front from the condenser to the drier.
My big question is oil. My denso compressor is pre-filled, like yours. But that's all you did? I have read other threads that say that I need to add oil to each component. Specifically 10cc's (0.34oz) to the drier. Condenser 40cc's (1.4oz). Evaporator 40cc's(1.4oz). And compressor 140cc's (4.9oz). I am leaning towards believing them because how do the manufacturers who made your compressor know that you are changing the oil in the other components as well? I'm thinking they just send the compressor with what that one part requires for oil.
Last question is the fittings. I have the new R134a adapters and removed the schrader valve from one of the R12 fittings. The other adapter fitting does not have a valve in it and sits much closer to the R12 valve. Do I just leave that one alone?
Again great write up. I appreciate the time and help!
07-27-2017, 10:12 AM
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Ah, the anonymous "other places somewhere on the internet."
First, the TSB calls for 100cc total of PAG, not 230cc if you add up your list. I think that tells you something about your other sources. Unless you think "they" know more about Toyotas than Toyota does.
Why do you use oil at all? Are there moving parts? Sure -- in the compressor. The only reason (so far as I know) to add oil to the drier is it is easier to reach the drier than the compressor, and to get the oil INTO the compressor you have to spin it. Wouldn't it be better if the oil STARTED in the compressor, already lubing all the parts?
Using a little extra oil probably wouldn't hurt, but you're talking about more than double the required amount. That sounds like trouble to me.
It sounds like you got two incompatible adaptor fittings. The ones I used have their own valve, so I needed to remove the core from the existing R12 port. There are also adaptors that don't have their own valve, just an "extension" to reach the existing valve. Perhaps that is the type of your second adaptor.
First, the TSB calls for 100cc total of PAG, not 230cc if you add up your list. I think that tells you something about your other sources. Unless you think "they" know more about Toyotas than Toyota does.
Why do you use oil at all? Are there moving parts? Sure -- in the compressor. The only reason (so far as I know) to add oil to the drier is it is easier to reach the drier than the compressor, and to get the oil INTO the compressor you have to spin it. Wouldn't it be better if the oil STARTED in the compressor, already lubing all the parts?
Using a little extra oil probably wouldn't hurt, but you're talking about more than double the required amount. That sounds like trouble to me.
It sounds like you got two incompatible adaptor fittings. The ones I used have their own valve, so I needed to remove the core from the existing R12 port. There are also adaptors that don't have their own valve, just an "extension" to reach the existing valve. Perhaps that is the type of your second adaptor.
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