Repairing AC hoses

[Sunroof]

I need suggestions on this one fellas.

I have an original "red" cloth covered AC line (low pressure side) that runs from the compressor to I believe the drier in the front drivers side wheel well. The hose is not crimped down on the fitting, rather two standard hose clamps were used to hold the hose to the fitting. I want to believe that was the source of my leak and slow deterioration of cooling last summer.

My mechanic said that it can be saved with a special fitting that does not require the hose to be removed out of the car (what a pain that would be). I believe the fitting has a wrap around crimp like shield of some sort that is tightened over the hose to hold it in and retain pressure. Being that this is on the low pressure side, I would think its worth a try to avoid a huge expense in fishing out that line and replacing the whole thing.

The big question then is.......what can you use if you have a male fitting coming out the low pressure side of the compressor that will hold a hose in place and will not leak?

Thanks
Regards
Bob
73.5T

[stormcrow]

Bob,

American hose and fittings should have the proper fitting for the hose. One question I have is that you said the hose goes to the dryer. If that's the case, then that hose is on the high pressure side of the compressor. However, if it comes directly off the compressor and towards the front of the engine, then it's the low pressure side.

I replaced my high pressure side with copper tubing last year. It was a pain, but the high pressure side has a tendancy to leak more often then the low pressure side.

Steve

[R22tech]

Bob, you say you want to believe that was the source of the leak. Have you had it checked with leak detection? If so, what kind of leak detection are you using? I agree with you, that is PROBABLY the source. I would like you to CONFIRM that it IS the source. If so, a new line would be the proper repair-sorry. That being said, I have a fuel line with the same leak point as your freon line. I used (2) worm gear clamps to fix it temporarily until I have my engine dropped for replacement of the line(which could be awhile). Keep in mind, the low side (suction line) will have about 35 psig while a/c is operating. It will have 100-150 psig when your a/c is off! Since you need a new line anyway, you can get creative with attaching that hose to the male compressor fitting. Just make sure you don't use any kind of sealant or goop that could enter the interior of that line or you will contaminate the system badly. The suction line DOES NOT like to be open for any length of time, so plan your repair in advance and don't make the repair under high humidity conditions. The result may end up as a sealed system that doesn't cool properly! I would be happy to help you diagnose the system, the repairs are up to you- I fix central a/c sytems and houshold refrigerators. Car a/c systems require different tools of which I don't have. Let me know.

[Sunroof]

Thanks...
I believe your right as to the low pressure side and that it may go to the front condenser or evaporator not the drier. I see so many hoses that its tough to sort them out! How to fish any of these hoses out is a challenge enough. I was slowly loosing cooling throughout the summer and although the system was not tested it was the opinion of my mechanic that the hose clamped area was the possible source. I have an updated compressor and most of the hoses including the high pressure side has been replaced.

At this point if I can manage to successfully clamp that low pressure hose on properly it may be cheap fix until I have to replace the clutch along with several hoses as well. The hose is the original red fabric covered type and your right about replacement, but I have to wonder how tough it is to get out and replace.

I appreciate the info on not using anything that can impact the system relative to sealants, adhesives or even humidity.

Bob

[jclc]

Bob,
I have a 74 with the red hoses and there seem to be plenty of potential leak places in the system.

I have a hand-held Freon leak detector you are welcome to borrow (its about size of a walkie talkie). My car would loose cooling in a couple of years so I bought this gadget to check the whole system. I found no leaks anywhere, so my slow leak must have just been the permeability of 50 feet of those old red lines (yes, I checked to be sure the leak detector really worked).

Im in midst of reassembling my AC system after painting car and replacing all AC hoses with barrier style, but I should be done with it in a few (4-8) weeks if you can wait that long.

Jeff Craddock
Orange, CA
74 911 Coupe (Soon to be Speed Yellow)

[bonedaddy]

I'd encourage you to check out a tech article at the Pelican site http://www.pelicanparts.com/techarticles/mult_AC_faq.htm/Mult_AC_faq.htm. It describes the "bleeder" hoses that were originally provided, and why you may be having difficulty locating a point source for your leak. It is very likely that you are losing a minute amount of refrigerant over the entire length of the hose which, over time, will result in a low charge.

It may make sense to try a stopgap method, but because of the type and age of the hose, I'm afraid the long term solution is to replace your aging hose with the non-bleeder type, and with the properly applied flare fittings. I wouldn't recommend copper because of the amount of vibration in the environment of an automobile.

Any time a refrigeration system is opened, it is advisable to evacuate the system before recharging. Otherwise you can end up with moisture or air in the system. Moisture can deteriorate the internals and freeze at the expansion valve. Air is noncondensible and can raise your head pressure inordinately high (bad news in a Porsche which is notoriously low on condenser capacity as it is).

I'm not trying to scare you from making a short term repair, but I think that in THE LONG TERM you'll need to bite the bullet and follow all the rules.

I'm not sure if yours is factory or one of the aftermarket systems such as VPC, but the above applies in either case. The folks at http://www.scottsind.com/ may be of some help to you also, and can supply customized lengths of the non-bleeder hose with fittings.

[stormcrow]

Not to get into a dispute over copper vs rubber, but the 3/8 acr soft copper line on the high pressure side is well secured and does not vibrate.

The reason for copper is that it was a lot easier to install and a lot cheaper than the barrier hose for the high pressure side. There is nothing wrong with using barrier hose but the cost difference made me lean more towards acr copper. All fittings used were high pressure brass flare nuts which can be pruchased at any hardware store. The total for tubing and fittings - $65.00.

As you well know, alunimum tubing is used where vibration is not a problem. I still have the barrier hose going to and coming from my condenser, along with the discharge from the compressor to the condenser.

Steve

[bonedaddy]

I must admit my misgivings about copper are not from personal experience. I was warned not to take that route by others, so I've never actually tried it. It's hard to judge what will happen over a period of many years. Flexible hose has it's own problems over time--deterioration and cracking--so you make your choice and take your chances.

[stormcrow]

My primary occupation is commercial heating/air conditioning. When I decided to go with copper for the P-car I didn't give much thought about deterioration. ACR soft copper is different than the copper you buy at the plumbing supply house or home depot. It has a thicker wall thickness and is designed for high pressure unlike plumbing tubing.

The only thing that I could see that would cause a problem for copper is if a rock flattened it out. With it being strapped to the underbody it does have some protection, and the underbody acts as a heat sink and helps remove heat/head pressure.

I could have used steel tubing but I would have to measure each bend and use a tubing bender which would make a little harder to install but it could be done. With soft copper, if your careful, you can pretty much bend it by hand without flattening it.

The best thing about it is you only have a joint at the h/p side of the compressor, two at the condenser, two at the filter/dryer, two at the front condenser and one at the evaporator. If there is a leak, it's a lot easier to find.

Steve