I am thinking about doing this myself. I think I'm going to flush with acetone and blow it out with compressed air.
http://www.peachparts.com/shopforum/showthread.php?t=120649&highlight=acetone

I like that idea to use the old expansion valve. I'm going to look into that.

My plan is to disconnect the receiver dryer and the outlet of the condenser then flush the acetone through.
blow it out with compressed air and replace the dryer and expansion valve.

This is a DIY project with regular hand tools and anything that can be purchased from Ace Hardware.
i would like to hear any thoughts on this if it will work or should I just take it to a pro andhave them do it.

Thanks

Danny

__________________
1984 300SD Turbo Diesel 150,000 miles

OBK member #23

(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination

Before you do anything with the refridgerant... Was the electric fan at the condenser running when you got your pressure readings? If so your pressures are probably OK. Also...if the system is low on freon the ac compressor clutch should be engaging and disengaging frequently.
I'd pinch off your heater hose to see if there maybe a problem with your heater (water control or actuator doors). The heater only needs to put out a little heat to completely mask any cold the ac is putting out.
That's my opinion anyway.

____________________________________-

83 300sd
3 ford
Ase cert. in ac

That would be possible if water were going into the cabin. But for the present the heater is bypassed. The compressor is not engaging/disengaging frequently. The fan was not running when tests were done.

__________________
1984 300SD 326,997 miles and counting . . . No wait, my odometer is still dead

There should be a sight glass on top of the receiver/dryer-look to see if it is clear(or a few small bubbles)when the a/c is running. I don't think that changing the oil is an absolute necessity-R12 will work with any oil(works best w/ mineral oil, but will tolerate alkylbenzene or polyolester(POE)). I personally would recover the old gas, pull a vacuum, leak test with nitrogen if available, replace the drier if I could afford it, evacuate and weigh in the recommended charge of R12(which should be on a sticker or plate in the engine compartment somewhere), and try it again-head pressure and low side pressures will vary quite a bit depending on engine speed and ambient/interior temps-the expansion valve I would wait until trying the correct gas first.

__________________
1982 300DT 190K (Diesel Purge + synthetic oil=smoothness at last!!!)
2004 Ford E-350 6.0 L PSD 227K
2006 Dodge Ram 3500 SRW HO Cummins 4X4 48RE 42K (brute force tow vehicle)
2005 Scion xB wife's rolling pop can
1993 GMC Sierra C3500 6.2 142K

" I don't think that changing the oil is an absolute necessity"

One item which changing the oil does is make sure the correct amount is in the system... draining and flushing the old out....and measuring what you install is the only way to know for sure...
NO book I have ever seen says it is ok to not replace the Reciever/Dryer once a system is opened up... or a refrigerant is changed... the dessicant sack is under oil... and neither the oil in a tube ... or the moisture captured by the dessicant can be removed by evacuation...
When the books even suggest putting fresh oil into the evacuation equipment they must think that having fresh dry oil in the actual AC system is relatively important...

Propane actually cools quite well and you will hear success stories from people who use it. I don't consider it to be any more dangerous than having pressurized gasoline under your hood but many states have outlawed propane as a refrigerant.

One very real problem with using propane that you will not hear when reading the success stories is that propane is too light to circulate the lubricant in your AC system. This could lead to lubricant related failures. The successful propane conversions used a second heavier refrigerant to move the lubricant. Then you get into the same old problems with fractionalization of blends and you are better off to avoid them.

I don't know rockin's financial situation, but on an old R12 based system, unless contaminated by water or something else, mineral oil is not usually very suspect to easy contamination by water(unless the system has been left open to air at all). I agree that replacing the dryer is always the best course of action(along with the oil and expansion valve), but no harm would come of trying a recovery/deep vacuum/recharge to see if the "non-approved" refrigerant is actually the cause of his problems.

__________________
1982 300DT 190K (Diesel Purge + synthetic oil=smoothness at last!!!)
2004 Ford E-350 6.0 L PSD 227K
2006 Dodge Ram 3500 SRW HO Cummins 4X4 48RE 42K (brute force tow vehicle)
2005 Scion xB wife's rolling pop can
1993 GMC Sierra C3500 6.2 142K

" mineral oil is not usually very suspect to easy contamination by water(unless the system has been left open to air at all)."

This has been discussed on the forum before....

If there is a leak .... all the books and pros I have read say that the system is so sensitive to moisture causing the formation of acid that a leak must be considered a point of contamination... even though this seems to be against intuition... there cas be vacuum relative to outside air at points in the system...and if the leak is near that spot then air/moisture can be pulled into the system...
This is the type of acid which can cause real havoc in a system... either the close tolerances and need for movement in things like the TXvalve... or the rotting out of the evaporator .... and we all know what a job replacing that is.....
So many of these things.... come down to a philosophical analysis of the cost verses the potential cost of problems if your assumption is wrong....
Usually the extra time and parts cost is WAY smaller than the potential.... and since the rules are known as to how to avoid it... and it should work years if done right.... I always go for the more conservative position... I got this attitude from having to do some jobs twice when in my 20's... I hate doing things twice.... and hate even more costing myself extra money due to cutting some little corners....