AC Compressor Hose Help

[wilson234]

A/C stopped working, trying to figure out why and uncovered that the hose from the deck lid condensor had cracked at the connection point at the compressor. I purchased this car from a prior owner that upgraded the AC to a Kuel R134a unit and all the lines appear to be new.

What are my options? I'm thinking about having a local hose shop put on a new end fitting, but I'm not sure if they will have one specialized that will have the pressure sensor fitting. Can I just eliminate the pressure sensor?

Anyone recommend a reputable shop online that I could mail the line for repair?

New one from Griffiths is $160 but it appears the hose itself is in great shape. It even still has the label on it. Trying to keep costs down, I believe a new fitting is fairly cheap.

At this point, it doesn't appear any fluid leaked anywhere, can I simply get a can for R134 like AC Pro and just recharge after the line is fixed?

Any suggestions/help would be appreciated.

[Chuck.H]

A good welding shop could TIG weld that back together if you removed it. Afterwards you need to pull a vacuum on the system for a few hours to remove air and moisture before recharging. I'm not an A/C pro so take this advice for what it's worth, almost nothing. But I do this work on my cars all the time.

HTH,
Chuck.H
'89 TurboLookTarga, 362k miles

[Jack Stands]

Looks to me like that is some type of compression fitting, so it shouldn't just be welded as the nut has to be able to be tightened. I would check with a local AC shop to see if they can replace the fitting with a properly crimped fitting, the pull the vacuum and refill with the proper amount of refrigerant.

[timmy2]

Compression ring inside the fitting has slipped off.
Metal line is compressed inside the fitting to seal it. May be too small to seal again (Probably)
The ring definitely is now deformed and can't be reused
You could try getting a new ring and tightening it all back together, or you may want to get a new piece from Kuel.

[GH85Carrera]

That is for sure a compression fitting. Don't weld it, you would never be able to tighten it without rotating the entire hose or the compressor.

I am not personally familiar with the compression fittings. My car has O-ring connections.

For sure you will need to pull a vacuum.

[Bob Kontak]

If the metal pipe when tight enters the compression fitting at the angle shown in the second picture, it probably has stress on it that is not allowing the compression ring to squish it properly.

Make sure, assuming you can take another whack at it, that all obstructions are cleared. Example, if the lower hose is not allowing the upper hose to seat properly, pivot it a bit to clear. You understand what I am getting at. Have to give the fitting a fair chance to do it's job.

Frankly, I like Jack Stands idea of getting a robust fitting on the end. A real and for true one. Looks like you can use a little extra length on that end anyways for added clearance.

Regarding a vacuum, it is never mandatory to pull a vacuum before recharging, EDIT - Scratch the previous sentence YOU CAN ENTER REFRIGERANT INTO YOUR SYSTEM WITHOUT PULLING A VACUUM, but you are not eliminating moisture that has crept into the system. Even the el-cheapo air compressor driven vacuum pump from Harbor Freight is WAY better than nothing.

As noted by brighton, spring the $60 for a new R/D. I would almost like to see you replace the RD without pulling a vacuum, than pull a knarly vacuum with an old worthless R/D. Do both though. :-)

Decent vacuum pumps are available at HF for $100 and you can get a nice Robinaire for $200-ish if you sniff around.

Electric Vacuum Pump - 2.5 CFM

Here is the el-cheapo

Vacuum Pump - AC Vacuum Pump w/ R134A & R12 Connectors

I think you need gauges to pull a vacuum.

Look at the bright side, you can get the medium (electric - $89) HF pump, gauges and R/D for the cost of an AC shop recharge.

AC Gauges - Save on this AC Manifold Gauge Set

One final note. You can buy a 30 pound tank of R134A at the local parts store for $100. That is equal to almost forty 12 ounce cans that sell for $15 a piece as you have a little line loss from transfer into your system.

You could be the AC God of your neighborhood.

[wilson234]

Appreciate all the feedback. What where is the R/D receiver dryer that is recommended for replacement? I'm leaning toward getting a new fitting and having a shop recharge the system.

[timmy2]

Dryer may be behind the drivers front wheel in the wheel well. Or somewhere else as it was customized.

[GH85Carrera]

Originally Posted by Bob Kontak

Regarding a vacuum, it is never mandatory to pull a vacuum before recharging, but you are not eliminating moisture that has crept into the system. Even the el-cheapo air compressor driven vacuum pump from Harbor Freight is WAY better than nothing.

I have never before seen anyone say that.

From everything I have ever read or heard a vacuum is very necessary before a recharge if you want the AC system to function.

There will be a lot of moisture in the system, and about 14 psi of pressure of air. Air is not a refrigerant. The moisture will freeze and clog up the expansion valve.

I run my vacuum pump for long time to make sure all the moisture is boiled out. I am a belts and suspender type. I pressurize the system with dry nitrogen after pulling a vacuum and then pull a vacuum again. I want a DRY system.

[Barrpete]

Originally Posted by GH85Carrera

I have never before seen anyone say that.

From everything I have ever read or heard a vacuum is very necessary before a recharge if you want the AC system to function.

There will be a lot of moisture in the system, and about 14 psi of pressure of air. Air is not a refrigerant. The moisture will freeze and clog up the expansion valve.

I run my vacuum pump for long time to make sure all the moisture is boiled out. I am a belts and suspender type. I pressurize the system with dry nitrogen after pulling a vacuum and then pull a vacuum again. I want a DRY system.

+1. Once the system has been opened like this one has, pulling a vacuum will be mandatory. Not only to get the moisture out, but the air as well.

[jimthe1st]

Originally Posted by wilson234

Appreciate all the feedback. What where is the R/D receiver dryer that is recommended for replacement? I'm leaning toward getting a new fitting and having a shop recharge the system.

Autozone carries the EXACT same R/D as you might purchase at Griffiths for 3 times the price.

UAC Parts/A/C Receiver Drier (RD10108C) | 1988 Porsche 911 Carrera 6 Cylinders B 3.2L FI | AutoZone.com

$21.99, R-12 and R-134a compatible.

[jimthe1st]

Originally Posted by GH85Carrera

I have never before seen anyone say that.

From everything I have ever read or heard a vacuum is very necessary before a recharge if you want the AC system to function.

There will be a lot of moisture in the system, and about 14 psi of pressure of air. Air is not a refrigerant. The moisture will freeze and clog up the expansion valve.

I run my vacuum pump for long time to make sure all the moisture is boiled out. I am a belts and suspender type. I pressurize the system with dry nitrogen after pulling a vacuum and then pull a vacuum again. I want a DRY system.

It depends almost entirely as to how long the system was open to atmosphere. In the above case pulling a vacuum will be required.

Whereas a simple QUICK replacement of a failed pressure sensor would likely not require....

[mfiazzo]

I would recommend buying a new line, this way you are sure it will not leak again. I would then fill the system with nitrogen to check for leaks before you pull a vacuum. A vacuum is essential if you want the system to be free of air and moisture. This will insure your system is operating properly. If you have a set of guages, you will need to pull a vacuum of 28". After you reach 28" of vacuum shut the guage off and make sure the system holds the 28" (just another way to check for very small leaks). Before you charge the system make sure you bleed the air out of the middle hose on the guage or you will have defeated the whole purpose of pulling a vacuum. Any other question PM me.

[mfiazzo]

Oh, and yes your pressure switch is required, the pressure switch will turn the compressor off if the pressure is too low thus preventing a compressor burn out. Saving you $$$$$$$$$$$$$$$

[Bob Kontak]

Originally Posted by Bob Kontak

Regarding a vacuum, it is never mandatory to pull a vacuum before recharging,

It is always done but it is not physically impossible to put refrigerant into a system that has not had a vacuum pulled.

Misleading choice of words on my part. I supplemented my comment to make it clear what I intended.

Thanks.

[Bob Kontak]

Originally Posted by jimthe1st

It depends almost entirely as to how long the system was open to atmosphere. In the above case pulling a vacuum will be required.

Whereas a simple QUICK replacement of a failed pressure sensor would likely not require....

Let's say you pulled out the refrigerant until the system pressure settled to atmospheric pressure. Only stuff goes out. Nothing goes in. Then you change the hypothetical switch in 13 seconds in AZ on a 110F day. Little to no moisture enters but you have no vacuum.

What is the operational impact on a system if you then fill your system up with refrigerant?

[mfiazzo]

Bob, I have seen many guys add refrigerant to a system or "purge" a system instead of pulling a vacuum and you are correct, the system will still work. It most likely will not work to it's full capacity, and it probably won't blow as cold of air as it would if you did it correctly. We all know in a Porsche we want the coldest air possible.

Since the line is already broken the system has been compromised so to do it correctly, he would have to pull a vacuum.

[GH85Carrera]

Any system that is open to atmosphere has moisture in it simply because all air has water in it. That is the relative humidity. The world's lowest recorded relative humidity value occurred at Coober Pedy in the South Australia desert when the temperature was 93 degrees and the dew point was minus 21 degrees producing a relative humidity of 1 percent. The average Phoenix humidity is between 35% to 40% according to my quick Google research.

I don't know what the volume of air is in a 911 system. With all the hoses and parts is is a decent amount however. My vacuum pump runs for a few minutes before it starts to struggle.

Yes, it is physically possible to charge the system without pulling a vacuum but it would be a waste of time and refrigerant. It is physically possible to charge it with propane but I sure would not want to try.

Within just one second of being open to the atmosphere it has pulled air to every part of the system. Every bit of that air has moisture in it, even if you live in Coober Pedy. 100% of the air has no value as a refrigerant and only messes up the AC system.

[JAR0023]

Maybe it's just me or the photos. To me, it appears that the fittings on both the discharge and suction line are tighter than 90*. Look at how the broken fitting is trying to enter the compressor at an angle. I get that it's loose but you can see the way the pressure from the hose wants it to enter.

The hoses should run front to back parallel with the rear rail, then 90* bend into compressor. With the tight bend in the fitting it is trying to pull the hose in tight toward the engine. I think the side loading helped cause the fitting to break. If it were mine I'd want the fitting to line up with the compressor with out any twist or side loads. -J

[Bob Kontak]

Originally Posted by GH85Carrera

Yes, it is physically possible to charge the system without pulling a vacuum but it would be a waste of time and refrigerant. It is physically possible to charge it with propane but I sure would not want to try.

...........even if you live in Coober Pedy. 100% of the air has no value as a refrigerant and only messes up the AC system.

I am not trying to pull a wwest here and pose a bizarre question in the hopes no one can answer it and then I become magically superior (in my own mind).

I simply do not know what the impact is. I suspect pressure differentials between high and low would be reduced by the dead space in the system and efficiency would be compromised. I also was thinking if you start with 14.7 psi and then add the correct refrigerant amount the system may run at higher pressure?