What components to swap, to update an R12 A/C system to R134?

Question

Would prefer to change only underhood components, maybe with parts from newer vehicles, from a salvage yard.

Wouldn't like to have the dashboard dissasembled.

Answer 1

This is NOT a DIY job!

You should ALWAYS change the receiver/dryer and any filters.  These can only be swapped with new items, NEVER use used ones!

The port adapters s***w down over the old R-12 ports and lock into place permanently.  Those will be included in the retro-fit kit, you can't use used ones since they lock down permanently.

It's HIGHLY recommended that you drain the existing oil from the compressor and refill it with the proper R-134a compatible oil.  A purist would also say to have the system flushed out and this is good advice.

The old refrigerant MUST be extracted by an EPA certified technician and recovered.  Then the system must be fully evacuated, tested for leaks and then serviced with the proper amount of R-134a refrigerant.

On some systems it may be necessary to replace the various pressure switches on the system as R-134a systems operate  at higher pressures than old R-12 systems.  These are custom parts on a per-application basis so used isn't an option there either.

Again, this isn't a DIY job.

Answer 2

The retrofit is fairly simple.  See these videos:

http://www.id-usa.com/how_to_videos.asp

Good Luck...

Answer 3

At the very minimum, the ac ports and reciever drier, neither of which you'd want to get used when you can get them new for 40 dollars. There is more to converting ac systems than just swapping parts.

Answer 4

Despite what you read in most forums on changing ALL of the components, it is NOT THAT COMPLEX.  You can do this if you REALLY REALLY want to.  But unless you have a failed part that has a serious leak, you can replace the oil, the fittings, and the gas.  Consider this for 1990 and newer cars.  You might be able to do this with older cars but I've done this on 91 and 94 without problems.  You WILL NOT get the same cooling out of an R134a system as you did with the R12.  It just won't happen.

Have a shop remove the R12 from your car.  It is illegal to vent this to the atmosphere.

Check the capacity of your system.  Usually on the passenger side of the engine bay will be a device called an accumulator.  It looks about the size of a lunch box thermos and will have tubes coming out of it.  On the top it will say something like R12 3LBS 8OZ.  This is the R12 capacity.  Convert this number to OUNCES to get the system capacity in OUNCES.  (Multiply the pounds by 16.)  Once you get the capacity in ounces, find the 80% to 85% value.  This is how much R134a to put in the system.  Note how much GAS vs OIL comes in the kit.  Get an extra can of GAS if the kit does not contain enough for your car.  (Big cars such as Suburbans require more gas as they have bigger systems.)

Get a kit to charge the system.  These are sold at Wal-Mart, auto parts stores, etc. for around $35 to $45.  There will ususally be three cans of R134a mixed with oil, a charging tube, and fittings to convert the old R12 to R134a style connectors.  

s***w the new fittings into place.  The RED fitting goes on the high side, the blue on the low side.  

Find the valve with the needle pierce and retract the stem all the way.  This is the TAP VALVE for the refrigerant cans.

PUT ON SAFETY GOOGLES AND GLOVES!  This is important!  You don't want to get sprayed accidentally in the eyes as this will cause frostbite!

If the can contains refrigerant and oil, shake each can vigorously before use!  If there are three cans of gas and one with oil and gas you only need to shake the can with the oil.

s***w the hose on the tap valve if it was not already on there.  s***w the can on the valve.  Connect the hose to the LOW SIDE.  The connector for the hose "retracts" when sliding on or off so pull back on the ring as you put it on.  Connect the hose to the newly installed fitting.

Turn the valve stem all the way down.  You will meet with slight resistance as the tapper pierces the top of the can.  Keep s******g down until it goes down all the way.  

Now back the valve up.  You should hear the gas start to flow and the can get cold.  Slightly swish the can around to help the flow.  If the AC system was open to the air and never completely vacuumed out, stop when the can is about half empty by s******g the valve back in.  When the valve is fully closed, barely unscrew the hose from the valve to let some gas back out.  This "sweeps" the air and moisture out of the system.  After letting most of this half a can out, s***w the hose back fully tight to the valve.

Open up the valve again and keep filling until the can is empty.  You may want to turn the can upside down to pour some of the liquid refrigerant into the system when it nears the end.

Close the valve.  Remove the hose from the fitting.  Open the valve to let out the pressure in the can and retract all the way.  s***w the next can on the valve and connect the hose to the fitting.  Unscrew the hose from the valve just a bit to purge the air out of it.  

Now for the fun part, start the car and turn the AC on FULL COLD or MAX.  Open the valve and start filling again.  You will get to a point where the compressor starts to kick in and out.  Eventually the compressor will kick in and stay in.  The compressor will kick in maybe after one or two cans and may not stay fully running until you have three cans in.

Keep repeating the can change until you get the 80% value calculated earlier.  If you have a thermometer that you can stick in the vent, put this in and check.  If you get  a vent temperature of 50F or less you are in good shape.  

NOTE: You will not get super cold as you did with R12.  When sitting in traffic the vent temp will not be as cold as you expect.  When driving, it will be much cooler.  After you filled the system, take the car for a ride and confirm this difference.

Answer 5

Nope the dash does not need to be taken apart. Depends on the Vehicle, but the parts come in a Kit from a auto parts store with the connections to to convert. But some models of vehicles with External Fans, you may run into a problem. The R134 run at a higher Pressures, which problems can occur with the A/C Compressor and the Clutch, and the Expansion Valve. Read which Vehicles can be converted, and make sure all leaks are corrected before you Convert to the new R134 System.