4450 AC

Hi guys, haven't been on here for a while but still lurk from time to time. Anyways, working on a friends 4450 with AC problems. Haven't really messed with the ac systems on these tractors in a long time but I noticed on the compressor it has one nipple with a schrader valve and the system has supposedly been converted to R134a as the tag on the compressor verifies that. Pump won't turn on and the lights are on in the cab so I'm sure it's low on refrigerant. It has the glass eye on the drier also but from my understanding that type is for R12 ??? I've got the gauges and vac pump and we bought the R12 to 134a conversion fittings as I only have 134A gauges....I would like to pressurize the system with shop air and check for leaks first before I waste several cans of 134A. I know to replace the drier after the system has been opened up. Any help or insight is appreciated.

I think air will induce moisture in the system. I use refrigerant with green dye in it.

(quoted from post at 10:17:34 05/14/23)

I think air will induce moisture in the system. I use refrigerant with green dye in it.

Click to expand...

''I use refrigerant with green dye in it.''

You have NO respect for anyone that will be servicing that system ''down the road''.

Refrigerant dye is NASTY NASTY NASTY when opening up and working on a system.

If there's a leak it will get some refrigerant oil on it and hold dirt and dust, indicating where the leak is, just like the NASTY dye.

RANT over, don't take me TOO seriously!

Introducing compressed air into an AC system isn't a very good idea. I suggest to pressure check with nitrogen or as wore out stated refrigerant with green dye. I'm curious what lights in cab are you referring to that could possibly be associated with AC system?

Do you know what, if anything, was done about the refrigeration oil in the system?

Without the correct amount of acceptable oil the compressor won't last long and will fill the system with metal filings as it does.

The original mineral oil for R-12 acts like oil and water and ''beads up'' rather than mix with the R-134a and travel through the system, lubing the compressor.

This can GREATLY reduce compressor life, although sometimes guys get by with that, at least for a while.

The ''correct'' way to convert to R-134a is to replace the compressor and dryer and flush the system thoroughly with AC system flush, then add ''PAG'' (polyalkylene glycol) oil.

An ''ACCEPTABLE'' method is to dump as much of the old mineral oil from the compressor, replace the dryer, and add ''POE'' (polyolester) oil.

Mixing the original oil with PAG oil or mixing PAG and POE oils can result in the system being clogged with jello-like SNOT.

The trouble is that guys mix and match and change things without leaving any clues/documentation as to what they put in the system.

If this is to be a dependably functioning system the most reliable ''fix'' is to thoroughly flush the system, install a new dryer and R-134a expansion valve and replace the old Delco ''A-6'' compressor with a ''Sanden-type'' modern compressor with PAG oil.

First off the lights are a timer system that didn't work that good there is a kit from deere to get rid of it I would start there.

Wore Out....Not sure exactly what's been
done with the oil...I still has the A6
compressor and R12 fittings. The owner
bought R12-134a fittings that I can adapt
to with my 134a gauges. Is there a color
difference between the two oils so I can
differentiate the difference between the
two oils ? The owners didn't do the change
the local Deere done the work yrs ago. The
pump has a sticker on it that's 134a
equipped but is the A6 compressor with R12
fittings....

I noticed there's only the high pressure switch and no low pressure switch. I will know more later today after work. Thanks for the help.

Hi Jim, on the above panel where the
controlls are at. There's two lights that
are on when the switch is on. I'm sure
they're associated with the AC system as
they have a AC symbol with a line in the
lens....Not at the tractor at the moment
but will verify later when I get home from
work. Thanks for the help. Really
appreciate it..

If the DEERE dealer did the change, the protocol was to thoroughly flush the system of ALL mineral oil/replace dryer and hopefully the compressor and install PAG oil.

ASSUMING they did what DEERE specified.

You CAN'T tell the difference in the oil by color.

Absolutely it will. But they don't want to
buy a $3-400 bottle of nitrogen for one
time deal..That's why the drier will be
getting replaced...

Why would they leave the old A6 compressor
when they changed it over to R134a ? Seems
they left the old system in amd done the
134a refrigerant...The drier has the sight
glass in it also..

(quoted from post at 13:50:13 05/14/23) Why would they leave the old A6 compressor
when they changed it over to R134a ? Seems
they left the old system in amd done the
134a refrigerant...The drier has the sight
glass in it also..

Click to expand...

Re-man A-6 compressors were sold well into the R-134a era, before the little compressors became the norm.

Fairly recently, you could still order the $$$$ A-6's, maybe still can.

As to the sight glass, some new dryers have had them and others not, well into the R-134a era.

They give some info even with R-134a, just don't try to add enough refrigerant to get rid of all the small bubbles.

The timer kit # re24456. This moves both pres switches to under the cab roof. I am not sure way you are talking about an a6 comp when they didn't use them in the 50 series or newer.

remember the old r12 fittings are the same for 134a commercial use. I do not use the adaptors just buy my 134a from a supply house alot cheaper and no need for the adaptor that are known to leak.

1. Dryers don't care what refrigerant is run through them.

2. Dye is fine for locating a small leak, but it is a catastrophe with a large one, so do a pressure test with a dry compressed gas first. Most of us have oxygen available, that will work if you follow safety precautions. If you cannot hear it (assuming your hearing is good) and pressure holds, then use soapy water on all the connections. Then either pressurize with refrigerant and use a detector or then use the dye. But remember that once you put dye in the system, its going to be a mess every time you use your gauges or vent any of the vapor or liquid out.