HELP Please-- Air Conditioner resto.

[GARMCo]

Hello-- have a early 70s Chevy truck and am restoring the air conditioning system. Installing new compressor, new hoses and & new accumulator. Using my old condensor & evaporator. During resto. I want to convert over to R134 refrigerant. Can anyone recommend conversion kit and/or describe the process? What type of PAG oil do I put in my new compressor ? How thoroughly (if any) do I need to clean out any old oil, etc. in the system ? ANy assistance is GREATLY appreciated. -- Tommy (garmco)

[JimKshortstep4x4]

I got my kit from NAPA and it included the oil. I think others have a similiar kit. We tried to clean the system out as well as we could. It is not back together yet but we are going to use nitrogen to blow out the lines and other parts just prior to reassembly.

Jim

[Zeke]

I wouldn't use PAG oil unless the system originally had it, bad for seals and o-rings. Ester oil is compatible with older systems when converting to R134.

[BobbyK]

I just converted over to a R-134 system.
I used stock GM parts.


I reused my orig. Evaporator core.I got it pressure tested and cleaned beforehand though.


Got a stock replacement condenser(new one).


and a R134 compatable receiver/dryer


Used a Sanden compressor with Alan Grove bracket's.


Switched over from the old POA valve to a new style FOT(fixed orafice tube).Just a newer way of metering the coolant that flows into the evaporator core.


I used BVA-100 oil for the system.More info on BVA oil HERE
A good choice if there is still trace anounts of old R-12 still in your system.


And I used a NYLOG on all the O-ring connections.More info on NYLOG HERE


Here it is all installed


I have not evacuated or charged the system yet.I'm kinda draggin my ass on that task.

I got all that I needed from Rick's Pickup Parts.He also gave me alot of helpfull info on doing this swap.

You can see ALL the pic's I took during the swap HERE
Just scroll down to the right photo album.

The pic's show the rebuild of the A/C system but I was rewireing the truck at the same time so those pic's are in there too.

[dmec]

why do you use the poa valve with the fixed orifice set up?

[BobbyK]

You'd use either a POA OR a FOT...not both.

The FOT(fixed orafice tube) is just newer technology.

I hear if you recalibrate the old POA it will work fine with R-134.

[Zonaman]

I have recently converted a '93 Saturn. Replaced compressor & dryer, had system flushed clean. Used whatever oil was compatable with R134a- ester I believe. Also, got all new O-rings.

PS

I know this is a little off the track, but has anyone ever used those vacuum pumps that use compressed air? Are they any good for pumping down an ac ? system?

[BobbyK]

Those are crap for evacuating an A/C system,unless the compressor your using is an industrial one.
It takes ALOT of CFM over a long period to for that type of vacume pump to work.

[BobbyK]

I forgot to mention that along with the FOT I used a POA eliminator kit from Old Air Products and got rid of my old POA valve.

Here's the POA eliminator kit.It uses a cutout switch which is pressure activated.That is what cycles the compressor.


here it is installed on my orig. evap. core.(orange cap)


I should add that the FOT(fixed orafice tube) takes the place of the origanal TX valve(thermostatic expantion valve) and is responsible for metering the coolant into the evap. core.

The orig. POA valve was replaced by the POA eliminator and cutout switch and is what cycles the compressor on and off.

[dmec]

thats pretty cool. so why does the small tube from the evaporator have to be connected to the adapter? i would think it could be eliminated. does this work with an acumulator or a dryer? im guessing it retains the original dryer set up. is this correct? just trying to get info. when i converted mine to r134 i replaced original evaporator with one from a later pick up with acumulator.

[BobbyK]

Well that little line could be eliminated but the POA eliminator accomodates it so no need to cut and solder that line.I don't think it has a function in this new setup.

It uses the Receiver/dryer not an accumulator.

[dmec]

thats pretty trick. what does that little guizmo cost?

[EdB]

Bobby, You posted some good info. My 70 is still working
fine stock. I know it is just a matter of time before I will have to
convert. I have used my stock of R12. I like the looks of that
Sanden compressor. I bet it takes a lot less power to turn than the
stock unit.
Thanks,
EdB

[BobbyK]

I'm told the Sanden compressor only takes about 5hp to run.The factory one I think was 30hp.

demc,I got the POA eliminator from ricks pickup parts(he's a member on this board).It run's about $80.00 buck's.