compressor and dryer

[long driver]

I need a compressor and dryer for my 93' and can't find any? Can anyone help?

[sc72]

Good morning. i bought the pump from goldautoparts.com 866 694 1729 i found the dryer and exspansion valve at our local Bumper to Bumper parts store. hope this helps and good luck.

[long driver]

Thanks for the info. Put it in yesterday. Thanks.

[sc72]

Great, nothing better than a cool Festy.

[bravekozak]

How does one know when the dryer has to be replaced?
Whats in the dryer? Is there some sort of molecular sieve that the caps have to be on until the lines are screwed together?
The replacement dryer does not have a glass at the top. Is the sight glass a necessity to tell if the system is full?

[sc72]

cool air

Bravekozak, the dryer has a moisture desacant inside, it's job is to grab moisture when the system is being used, if the system has been open for an extended period of time, the dryer will no longer be able to pull moisture from the system. Alot of the replacement driers no longer have the site glass and the site glass was to let you know if the system pressure was OK and to let you know if the system was low. i hope this helps. i'm sure some of the other members can help with the explanation.

[bravekozak]

I figured that the dryer should be capped/plugged immediately when removed otherwise it would absorb humidity from the air and become ineffective. I will let everyone know if the plastic cap that goes over the sight glass will fit the replacement dryer which is slightly smaller in diameter. They say that 134A can't use a sight glass. Cloudiness can lead to overcharching.

[Movin]

Did you purposely collect every old wives tale from every source possible
and post them in one short paragraph just to fun us ? LOL Good one!!

[bravekozak]

I just did a google search for "a/c dryer how it works" and found this.

RECEIVER-DRIER
The receiver-drier is used on the high side of systems that use a thermal expansion valve. This type of metering valve requires liquid refrigerant. To ensure that the valve gets liquid refrigerant, a receiver is used. The primary function of the receiver-drier is to separate gas and liquid. The secondary purpose is to remove moisture and filter out dirt. The receiver-drier usually has a sight glass in the top. This sight glass is often used to charge the system. Under normal operating conditions, vapor bubbles should not be visible in the sight glass. The use of the sight glass to charge the system is not recommended in R-134a systems as cloudiness and oil that has separated from the refrigerant can be mistaken for bubbles. This type of mistake can lead to a dangerous overcharged condition. There are variations of receiver-driers and several different desiccant materials are in use. Some of the moisture removing desiccants found within are not compatible with R-134a. The desiccant type is usually identified on a sticker that is affixed to the receiver-drier. Newer receiver-driers use desiccant type XH-7 and are compatible with both R-12 and R-134a refrigerants

Are you saying it's false?

The XH-7 (or any) molecular sieve should be able to be reactived with heat, by driving off the trapped water. Would putting the dryer in an oven damage or melt anything inside? I just want to drive the water out of the molecular sieve and reactivate it. It works by trapping and holding water in it complex pore structure. Some of the original uses for it was for trapping water and oil from depositing between panes of large insulated glass.

Chemists frequently use drying agents to remove water or other contaminants from solvents. Molecular sieves are one of the most effective drying agents. They consist of aluminum, silicon, oxygen and other atoms arranged in a three-dimensional network with open channels; the size of the channels varies depending on the exact ratio of aluminum and silicon. Manufacturers designate the most common channel sizes as 3A, 4A, 5A or 10A, where the number represents the approximate size of the channels in angstroms. Before a scientist can use molecular sieves as a drying agent, she must "activate" them by removing all traces of water and other volatile compounds. Normally, this involves heating the sieves to 300 to 320 degrees Celsius (572 to 608 degrees Fahrenheit) for about 15 hours.


I personally believe That the dryer is unservicable since it is intentionally welded, so that the dessicant cannot be replaced. The excuse being high pressure safety.

[bravekozak]

I found my answer to the reactivation question. It is exactly what I expected.

In the past, some have attempted to reactivate and reuse a filter-drier by heating and evacuating the desiccant. Heating and evacuating does actually remove much of the moisture and allow the drier to be used again. However, oils, carbon, and other particles are not removed during this reactivation attempt. In fact, the oil may be cooked into the desiccant, creating new contamination possibilities. The cost of a new filter-drier is not worth the effort and is not recommended.
Don’t allow a system to become an out of control chemistry set. Good piping practice, a nitrogen purge during brazing, a deep evacuation, and the proper installation and use of filter-driers containing modern and effective molecular sieve desiccants will prevent many system failures. Many compressor failures are blamed on the compressor when the actual cause was a system problem. That system problem may have been a chemical problem due to moisture.

I will replace my original drier with the one that is slightly smaller in diameter and use an extra fuel tank filler sleeve to wrap and hold it in the clamp. Besides, I stripped one of the connectors on the drier while trying to replace all of the O-rings.

[Movin]

AC systems are charged by the weight of the freon. Each system has a range that it can
operate in. Once near that range we fine tune the exact amount based on the temperature of the system at several places and the pressures while operating. The site
glass if present is an indicator as well, and can be used with 134 just fine. I don't
use it at all as I am looking for best system performance "tomorrow". This means
after years of playing with this stuff I know what temps and pressures I want to see
so that the best outlet temp will be achieved later in town and on the hiway.

The desiccant can be reused until the bag bursts or the media is contaminated.
The receiver drier cannot be flushed, cleaned or reused after an internal failure
of the compressor.

All debris in the system should be blown out with flushing solvent. All moisture
will be removed by using a good vacuum pump. Heat lamps on the compressor
and the receiver drier can speed the process in cooler weather. Caps will not
prevent condensation in the drier, just assume it was stored in a bucket of water
and leave the vacuum on long enough to remove the moisture. The desiccant
will clear quickly but it will take at least 20 minutes of good vacuum to clear
moisture from the oil.

If you have a lathe and welder you could rebuild them but they welded them in the first place to sell more parts and to guide you into compliance ..they want your money!

I see you added another post...Where does carbon come from? Do you really want to
remove good oil? That is exactly the kind of BS taught by the industry! The drier
can be reused until it is contaminated by a person or by internal compressor failure.
You can put a light bulb next to it to warm it in cold weather with no harm, just don't
over heat it and cause the bag to weaken. But , as you say, stripped bolt..You are
doing fine!

[bravekozak]

I see that there were two different drier part numbers. When I turn each one upside down, I can feel and hear a dull clunk of something sliding up and down. When I took the caps off the replacement drier from UAC, there was a lot of vacuum released from within. It did not have anything sliding or clunking inside. The stock plastic L cap clipped down on top of the replacement drier. The hard lines fit even though the replacement drier was a little taller than the original. For the sake of science (and other ff.com members curiosities), I will cut open one of the twenty year old driers to see exactly what's inside.

[bravekozak]

I took my "Texas Chainsaw" to the drier and after I opened it up, was very surprised to see how simple the design was. The clunking was just the dessicant bag sliding back and forth.
The only other feature is just the strainer. I presume the saw teeth are just there to form a drip edge. I am going to perform surgery on the dessicant bag to see what condition it's in. If it's not too oily, it probably could have gone back in the oven to be reactivated.

[bravekozak]

The dessicant is black!