how much trouble to put ac back on?

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rigrunner

rigrunner

rigrunner
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i have a 73 valiant 4door that im making my daily driver and last year after having probs with the engine i took off the compressor and drier and condensor from the ac that didnt work. the lines connections going into the dash were left open and i was wondering what i would need to get this back on and in working order or would i be better off trying to get and aftermarket system e\ven though the car already had air from the factory. thanks:read2:
 
Hi , you will probably need to flush the evaporator with an approved air con flushing agent , not the sort of job you can do at home - you will need to visit a car air con service person for that. The condensor if left open will also need to be flushed if its still ok and doesnt leak .The drier will need to be replaced and then the system re hosed. The compressor if left open will also be no good and to be safe , replaced with a new or reco unit
Unfortunately none of these jobs are really possible without the correct equipment apart from mounting the compressor , drier and condensor.Just remember to keep everything sealed as much as possible
ben
 
reassemble everything and install a new dryer and orifice tube. vacuum system and then pressure up with freon if it holds vacuum. You can get a vacuum that works with your air compressor for about 20. and a set of gauges for about 75. from harbor freight. theres a video on youtube that explains everything and how to charge it by a canadian guy thats very good. I did mine last year and had 0 previous experience.
 
thanks. im trying to decide if its what i want to do or not. from what i hear the factory compressors took a lot of power and really rob the gas mileage. what about changing to a newer style compressor? thanks
 
There is no orifice tube in this system. There's a TXV (thermostatic expansion valve) mounted to the firewall inlet on the high side of the system, with a capillary sensing tube pushed into a tunnel on the low side line where it enters the firewall. The TXV doesn't necessarily need replaced just because the system's been left open, though it's not all that expensive and not a bad idea.

The factory compressor is efficient in terms of power consumption; its downfall is noise and vibration. Because it has only two cylinders, the torque load on the drive belt is full of peaks and valleys. If the brackets aren't put together properly or the belts aren't tensioned correctly, you can get belt slap and squeal. Likewise, because of the two cylinders, you can get pumping/line noise audible inside the car if the high-side and low-side mufflers are deleted when the lines are rehosed. An inertia-ring type compressor clutch helps out a lot with the vibration and belt noise issues; they were made for both 6-cylinder and V8 applications. The newer compressor designs actually exert more torque load on the engine because of the higher cylinder count (5 or 7 cylinders in a Sanden/Seltec compressor) but for the same reason the torque load is a great deal less peaky.

To get this system reliably up and running, you'll need to do the flush and filter-dryer replacement already mentioned, carefully inspect the hoses and replace any that look (or test) leaky or about-to-be-leaky, replace all the O-rings and gaskets. You will also want to consider throwing a new shaft seal in the compressor; they're cheap and it's easy, but if it starts leaking shortly after you charge up the system, it'll cost a lot more 'cause the system will have to be evacuated etc., new filter-dryer all over again.

You may want to consider taking the opportunity to upgrade to a parallel-flow condenser; see here. This will improve cooling performance and greatly reduce head pressure on the compressor, which in turn reduces its torque load on the engine.
 
Dan caught me. I was working on a brand x. Couldnt stand no air in the tx. heat. Glad he filled in the mopar details. My point was I had never worked on a/c, in fact it was the first thing I stripped off most cars. But with a few youtube videos, a hundred dollars worth of tools and 200 bucks for a compressor and dryer I was cool in the tx. heat. Go for it. You will be glad you did.:headbang:
 
daredevil said:
Dan caught me. I was working on a brand x. Couldnt stand no air in the tx. heat. Glad he filled in the mopar details. My point was I had never worked on a/c, in fact it was the first thing I stripped off most cars. But with a few youtube videos, a hundred dollars worth of tools and 200 bucks for a compressor and dryer I was cool in the tx. heat. Go for it. You will be glad you did.:headbang:
Click to expand...

sorry as I am in australia , things are a little different here.
Refrigerant is not available to the general public and you need a CFC users liscence to purchase any refrigerant and also legally to use it.Theres even a huge fine for releasing any refrigerant to the astmosphere.
If you dont evacuate the air from the system prior to a re charge , the unit will never work as well as it should , a decent vac pump in australia is about $700.00. Nitrogen is what we use for leak testing here , not sure if thats an option for you
ben
 
here is how its done. drain the oil from the compressor. reinstall the proper amount of polyolesther oil. mount everything hoses etc. and use nitrogen to pressurize the system to 100 pounds. check after a couple of hours. if the pressure has not dropped than you are leak free. if it drops use soap on all connections and look for bubbles. that would be your leak. fix your leak and repressurize. check again. then evacuate the system and then charge it. using 134a refrigerant. of course you might want to make friends with a refrigeration/ac mechanic to accomplish this. instead of spending 400 bucks on **** you may never use again give a hundred to your buddy and get it done right.
 
hi dan just to let you know the only time a filter drier needs replacing is when it has absorbed enough moisture to not allow enough refrigerant flow through it. that only happens when a system runs in a vacuum therefore sucking moisture and air into the system. most a/c systems prevent that by using a pressure control that cuts the compressor off at about 20 psi thereby preventing a vacuum to occur. so the next time someone wants to sell you a new drier you can ask them why. Paul
 
I have had some R-12 driers collapse when re charges with 134a and cause a blockage .This is why I recomend replacing them.
And besides if its a universal number 5 or 6 they are under ten bucks , so why wouldnt you change it while you are going
ben
 
tasvalowna said:
I have had some R-12 driers collapse when re charges with 134a and cause a blockage .This is why I recomend replacing them.
And besides if its a universal number 5 or 6 they are under ten bucks , so why wouldnt you change it while you are going
ben
Click to expand...
changing the filter drier is allways recommended when a system has been open for any length of time .and when changing refrigerants as R134 a is a cleansing agent as well as a refrigerant. it tends to flush all kinds of **** from the system eventually ending up in the drier. what i was saying is that just because that same system loses refrigerant later on it is not necessary to change the drier unless the system has run in a vacuum. i don't wash my car when it is allready clean. paul
 
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