A/C help please

I'm sure JRick will be posting his glorious A/C conversion piece here shortly BUT! I am doing this myself this weekend, and I must say this. If your system leaked the original refridgerant than that is where you must first fix it. The switch should work fine, it is simply not turning on since there is not enough pressure in the system to engage the compressor (you verified this by jumping it The best bet would be to have the system professionally evacuated of any remaining R-12 ( Its in there... just not pretty.) And proceed to clean out your evap, and your condensor, replace your suction line/Accumulator, mine cost $65 from the Zone, and then Follow the rest of the directions in Jrickner's post. It is very informative, also, if you were to google "mustang r-134a conversion" you would get a result for stangnet, and there is plenty of information in that thread as well!

[It is illegal for a company to sell any refrigerant other than R134 to a person who does not have an EPA 608 or 609 certification. That includes Freeze 12.

See http://www.epa.gov/Ozone/title6/608/overlap.html for more details


R134a Air Conditioner Conversion and recharge instructions

Revised 17-June-2011 to include Freeze 12 as an alternative refrigerant

Color Legend:
R134 specific items and instructions are in red text
Freeze 12 specific items instructions are in indigo text
Items and instructions common to both R134 and Freeze 12 are in black text

Tools and materials you will need:

Gauge set for recharging = $20-$120 – check out the pawn shops for a bargain before you pay retail.
See Harbor Freight Tools for an inexpensive gauge set.



Vacuum pump – I use an old refrigerator compressor = $20- $40 at used appliance stores, or go to the Dump and get one for free. Be sure to have some R12 compatible oil handy to keep it lubed up properly.


O ring seal kit = $8.

Replacement accumulator/dryer assembly with hose $55-$75


Alternative refrigerant – Freeze 12 – it will allow you to skip flushing the system and reuse the original accumulator/dryer under certain conditions:
1.) If the A/C system has not been open to air for more than an hour or so.
2.) Or if it hasn’t out of refrigerant for more than 5-7 days and the system is till sealed up with no open or disconnected lines.
If either of the above is not true, you must replace the accumulator/dryer assembly.

Freeze 12 refrigerant: $15-$16 per 12 Oz can on eBay. Get 3 cans, 2 for the initial charge and 1 spare for a top off charge.
Use R12 compatible mineral oil, 6-8 Oz. This may be difficult to find or expensive (~$20 a quart)
Do not use PAG oil in a Freeze 12 system without flushing it first.

Freeze 12 refrigerant charge= 26-28 Oz plus 6-8 Oz R12 mineral oil on an empty system. A recharge may only require 2-4 OZ of R12 mineral oil if you only replaced a line, hose or seals.

A/C systems that have had a compressor failure must be flushed. Failure to do so will result in the floating trash left behind from the compressor failure destroying the replacement compressor.

R134a = $11-$16 a can – takes 2 cans.

R134a PAG or Ester compatible oil = $7-$12 for an 8 oz bottle .

Pump to force cleaning fluid through the system $20-$50 (may use compressed air to do the same thing).

R134a charging adapter = $13 (I cut mine up to use it with the R12 gauge set that I have had for a long time).

Plastic tools to disconnect refrigerant lines - 1/2" & 5/8" = $4 each.

Flushing agent - Discount Auto Parts has some flushing solvent in a 1 gallon plastic bottle - try that first. Or use Mineral spirits = $4-$5 a gallon, tetrachloroethylene =$5-$10 a gallon, takes 2 gallons of either one.

Miscellaneous hoses and fittings to adapt the flushing pump to the system, and the R134a adapter to the R12 gauge set = $15.

R134 Refrigerant charge is 26-28 Oz plus 6-8 Oz of PAG 100 oil.

R134 Conversion Instructions:
I did a R134a conversion on my 89GT, and used all stock parts. You will need to replace the dryer/receiver (about $75 if you get the one with the hose made as part of the unit), and should replace all of the rubber "O" ring seals as well. You will need to drain all of the oil out of the compressor and replace it with new R134a compatible oil.

R134 instructions (skip this if you use Freeze 12)
Keep in mind that to fulfill the requirements of the EPA, you are required by law to recover any refrigerant that still remains in the system. How (or wither or not) you accomplish this is up to you. Connect the charging gauge hoses to the service ports on the A/C (red gauge = high pressure, blue gauge = low pressure) and open the valves on the gauges to dump the remaining refrigerant (if any) into your "freon recovery system", whatever it may be. Disconnect the charging gauges since you are finished with them until you are ready to fill the system with R134a. Next comes the nasty part – in order to get all the old oil out of the system, you will need to flush it with special flushing solvent, or mineral spirits (ok) or tetrachloroethylene (better, but may be hard to get). If you leave the old oil in place it will congeal and reduce the heat transfer in the condenser and evaporator (read that it won’t cool good) and possibly damage the compressor.

Disconnect the compressor and remove it from its mount to flush it with cleaning solvent. Pour about a cup of solvent into the suction port and turn the compressor center hub about 10 turns while shaking the compressor to move the solvent around inside the compressor sump. Drain the flushing solvent out and continue to turn the center hub by hand to force out any remaining solvent. Then fill it with oil: add about 6-8 oz of the new oil to the compressor large suction fitting. Turn the compressor center hub about 20 turns as you turn the compressor face up and face down to distribute the new oil inside the compressor. Catch and replace any oil that comes out of the compressor.

Connect the pump (I had an electric sump pump I bought for $20) to the hose from the high-pressure side of the compressor. Alternately, you could use compressed air to force the cleaning fluid through the system. I didn’t like to do this since compressed air has lots of moisture in it, which is death to A/C systems. Pump the cleaning fluid through the system and let it come out the hose that was attached to the old dryer/receiver. I used 2 gallons of mineral spirits and pumped it all through the condenser and evaporator. The expansion valve is located near the firewall in the high-pressure line of the evaporator, and may cause the cleaning fluid to trickle through the lines at a very slow pace. You may want to pump cleaning fluid through the evaporator and condenser separately to speed up the process.

Both R134 & Freeze 12
Next comes the changing of all the old "O" rings so that the chances for leaks is minimized. Use the plastic connector tools to separate the lines, place the extended collar part of the tool so that it faces the large part of the connector and push inwards: this expands the spring so that you can pull the tube apart. You may need a helper to push on the tool while you pull on the tubes to separate them. Install the new "O" rings: be sure to coat them with new oil when you put them in. Install the new dryer/receiver, refrigerant service port adapter, compressor, add about more 4oz of oil to high pressure line and tighten up all the lines. Close the hood, start the engine, let everything get warm under the hood, but don’t add the refrigerant or turn the A/C on. Connect the charging gauge hoses to the service ports on the A/C (red gauge = high pressure, blue gauge = low pressure) and open both valves, then connect the center hose to the vacuum pump. The purpose of this exercise is to heat up the system so that when you vacuum it all down (yes, you will need a vacuum pump- mine is an old refrigerator compressor), that all the air, vapor and moisture from the cleaning fluid vaporizes and is removed from the system. Vacuum it down for about 30 minutes, this should give you about 28" of vacuum or more inside the A/C system. I have a vacuum gauge "T" connected into the vacuum pump line so that I can accurately watch the vacuuming process. This is a good time to take a soda and sandwich break since it doesn’t go faster if you watch it.

the R134a service fittings on the system: the red goes on the high side and the blue on the low side. This will help others identify that a R134a conversion has been done on the system.

Typical low pressure side R134 coupling

Typical high pressure side R134 coupling

Charging instructions for both R134 & Freeze 12:
Remove the electrical connector from the dryer/receiver and jumper the two connections inside the wiring harness side of the connector together: this allows the compressor to engage in spite of low pressure/no gas in the system. Close both charging gauge valves, and then disconnect the center hose of the charging gauges from the vacuum pump and connect it to the refrigerant can tapper. Put the refrigerant can in the can tapper and screw it down with the can tapper valve closed, then open the valve. Loosen the hose at the center connection of the charging gauge set until the refrigerant squirts out: this purges the line of air and moisture. The refrigerant is added through the low pressure side of the system, so open the low pressure gauge valve to add the refrigerant. Start the car and take note of the idle speed, then set the idle speed up to about 1200-1500 rpm, and turn the A/C on inside and set the fan speed on high. Watch for the pressure on the low side to drop off as you are filling, and the refrigerant can will get warm and stay warm. This tells you the current can is empty and needs to be changed for a fresh one. Before you disconnect the can, be sure to close the valve on the refrigerant can tapper.

Watch the high side pressure on the charging gages and regulate the adding of gas to keep the high side pressure under 350 psi. You will probably need a fan in front of the car to keep the readings below 350 psi. I had to put the refrigerant can in hot water while I was charging the system with it, or else the can got so cold that it quit flowing. Use caution when you do this so that you don’t get water in the charging adapter when you change the cans. When you have added the 2 cans of gas, the high side will read about 250-300 psi and low side about 28-38 psi. Turn the idle speed back to where it was, turn the A/C off, disconnect the charging gauges, and re-install all the caps on the service ports. Remove the jumper from the low pressure switch harness and plug it back on the switch connectors.

R134 only
Then put the R134a Service Sticker on, secure all the loose wiring on the system and you are done.

The typical sticker looks like this, yours may be different.

I hope it cools good, mine doesn’t get quite as cold as it used to driving around town.

The above technical note is for informational purposes only, and the end user is responsible for any damages or injury. The end user bears all responsibility for proper recovery/disposal of any R12 refrigerant.
I have an EPA 609 MVAC certification. And yes, you can shortcut the process, but there are negative factors if you do. Sooner or later, something will cease to function like it should. Shoddy work is a time bomb ticking away, waiting to explode.

AFB said:

Ok so I did a little research and stumbled across Freeze 12 freon. Im sure if this was ok to use, you all would have suggested it. It appears to EPA compliant Let me know what you guys think, seems like I can just recharge my existing system with this? thanks

Adam

Click to expand...

I am using Freeze 12 and so far it seems to be working good. Freeze 12 is R134 with a little R410 added to make the mineral oil soluble and flow like it needs to flow.

Freeze 12 is available on eBay without any kind of license or restriction - 3 cans for ~$50 & free shipping. All canned refrigerants are gas when you charge the A/C system. Freeze 12 is no more dangerous to handle than R134: it is less dangerous than rattle can spray paint. You need to take reasonable precautions when handling any pressurized gas. Wear safety glasses or a face shield, and have plenty of moving air when you charge the system. The moving air keeps the car from overheating and the exhaust away from you.

I just bought my 3 12oz cans of r-134a at walmart for $10.77/can. They have a 10buck deposit which you can get back by bringing the empties back to the customer service desk. In reality, if you get new hoses, then the only thing you need to worry about with the retrofit is to clean your evaporator, compressor, and condensor. You can use a condensor out of a 94-95 mustang without any modification that a switch of the brackets side to side and some hammer tweaking. This will give you a much more efficient condensor design anyway. I'd hate to use Freeze12, alot of shops wont touch your car if you have it, since it can contaminate their systems. R-134a got my center vent really cold a few hours ago... I'll give you an update tomorrow, but I'm using all stock parts.

Bottle of Ester Oil with UV dye - $8.00
3 cans of r-134a 12oz - $32.50 - (+$30 refundable deposit)
Gallon of A/C Flush - $24.99

Aside from other hard parts and the adapters thats All I got.

I would get the gauges from Harbor Freight... they at least have a vacuum reading on the low side... the cheap autozone ones dont.

Yeah... I can find a few tanks or virgin cans on craigslist for about 15 bucks for a 12-14oz can. If you can find the parts to use them... Go for it! Make sure you have your EPA 609 Cert... You can get in trouble otherwise... Another reason I chose to retro to R-134a... My vent was blowing cold before my old Discharge line didn't like the pressure. Friday I'll have vent temps with the stock setup on r-134a.

Well... Picked up the hoses, and another can of R-134a... they are now $11.85 a can... go figure... And found that after I charged my A/C, the vacuum going to my heater/ac controls isn't working right. So I can't get you any vent temps, but! I do have some nice cold air coming at my legs and the top of my head! Either way you go, if your replacing hoses go for the R-134a, and if your getting a new condensor with the upgrade to r-134a get one from a 94-95 mustang. They fit right in and work better with the r-134a. Good Luck, and if you need any help, just buzz the forum.

Just did mine over as well, I replaced all the system o-rings, got a new accumulator, used the 10 dollar harbor freight vacuum pump to pull vacuum for about an hr, vacuum tested the system for 30mins. Did a oil charge, leak sealer charge, 2 3/4 cans of freeze 12. Works great spent a total of $120 bucks to get it going again (lucked out with the dryer had the hose and was only 35 bucks new off ebay)

my 1988 mustang had dealer installed a/c. i will convert everything to a factory type a/c. i already bought all the brackets needed to install a factory type a/c compressor, accumulator, evaporator, a/c lines along with a 94-95 type mustang condensor. everything will be brand new. what type of oil should i use? how much oil should i use? which components should i place the oil in? how many ounces should i use of r134a?

Read my post at the beginning of this thread. There is a complete R134 conversion tech note with everything you need to know.