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Newbie - 1972 Valiant

Discussion in 'A Body: Duster, Valiant, Dart, etc' started by Nebraskaorville, Aug 10, 2017.

  1. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    If there are bad seals, you need to open the system to replace them. That means changing the drier canister and gaskets. If this system is still R12, it uses mineral oil and PAG must NOT be added unless all components are thoroughly flushed or replaced. If converting it to R134a, ester oil is the best choice for compatibility.
    Is the system empty? If not, the refrigerant must be recovered professionally.
    If you have the education and tools, you can service it yourself. After repair, a vacuum of 29+ inches must be drawn before recharging. The proper amount of R134a is about 80% of the original R12 capacity, judged also by appropriate system pressures.
     
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  2. Nebraskaorville

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    Thanks Bob!
    The system is empty. What kind of a seal goes between the compressor and the two main lines feeding into it?
    Also - i have some "refrigeration oil" that i came out of my dad's shop - probably from the late 60's. I dont think a full rehab is in order, but can i just pull one of the main lines and add some oil there? Just trying to make sure the compressor isn't running completely dry.
     
  3. Nebraskaorville

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  4. AllanC

    AllanC Well-Known Member

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    Does the vehicle have the original issue Chrysler RV2 air conditioning compressor? See attached image.

    Chrysler RV2.gif

    You can do a Google search for seals "Chrysler RV2 compressor" and you will get several sources. One in Arizona is ACKits.com. Another is Santech : Automotive Air Conditioning Service Parts : Santech Industries, Inc. (at http://www.santech.com/products/service-parts/ ) You might check these sources and see what seal kits are available if your vehicle has the RV2 compressor.

    You need to commit to doing a complete restoration / rebuild on the air conditioning system. Do not just add oil. If you are not ready to do the A C system rebuild, disconnect the electrical line to the compressor clutch. In that way the compressor will NOT be accidentally engaged and run and then you can wait to do the rebuild on your schedule. The A C pulley will just spin on the clutch pulley bearing but the compressor shaft will not rotate.

    I would definitely NOT use 50+ year old oil in the A C compressor. Has the container remained tightly sealed so no moisture was absorbed by the oil? Highly unlikely.

    Bob L gave excellent advice on converting the system to R134a. At a minimum the compressor needs to be removed and thoroughly flushed. What is the condition of the suction and discharge lines? Those should be rebuilt (use metal fittings at each end) with modern, barrier type refrigeration hose.

    The condenser should be removed and flushed. It is probably a serial flow (one path in and out) and those can be flushed. Any debris? Any signs of oil accumulation indicating leaks?

    Taking a "poor boy" approach and a "hit and miss" on automotive air conditioning work will give you less than desirable results and lots of frustration.
     
    #104 AllanC, Jul 12, 2018
    Last edited: Jul 12, 2018
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  5. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    And again, is it now R12 or R134a? R12 uses screw-on connections, R134a uses quick-connect collar fittings at the ports.

    That oil should not be used, it's too old and will have moisture in it, and possibly have broken down. And it would only be good for an R12 system, if I'm reading the label correctly.

    If the system is R12 and will be recharged with R12 (almost impossible to find), it will need new mineral oil. If it has been converted already, it will need ester oil. This is still available, but starting to get scarce. Since you don't know how much oil is in the system, you'd have to flush everything. Too much oil hurts efficiency and is not good for the compressor, too little will burn it out. Typically most systems hold about 8 oz oil when new. But unless you flush, you don't know how much to add.
    When flushing, I've used a citrus flush. But I found I didn't use enough compressed air to get all the liquid flush out, and so the system on that car doesn't cool well. Make sure to use a lot of compressed air for a long time to get all the flush liquid out.

    On Chrysler products of that vintage, the seals between compressor and hoses may be flat metal gaskets, or may be O-rings. Either way, thoroughly soak all of the gasket and both mating surfaces with compressor oil before installation, or you won't get a tight seal.

    When pulling a vacuum, pump for about 10 minutes and shut off, and check gauge for leaks. It's normal for residual moisture to sublime and reduce the vacuum from 29 1/2 to about 28 or so over several minutes, but a faster change or lower reading is a leak. Once you determine it's OK, pump for another hour. Then wait 20 minutes or so, and reading should not change. Once it doesn't change, all the moisture is out that can be removed. Then you recharge.
     
  6. valiant67

    valiant67 ...

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    I think you really only have two choices, OK three:
    1) Fix the system as Bob and Allan have detailed.
    2) Remove the compressor for now and either use shorter belts or install an idler pulley setup from a non-A/C in its place (shorter belts may rub so it may not be an option). Block off connections when the compressor is removed.
    3) Drive it with the non-working compressor until the compressor locks up.
    I've used option 3 regularly on older cars with non-working A/C with no issue. As long as the clutch doesn't kick in, the A/C compressor won't spin. If you find the clutch is engaging the compressor, replace the clutch.
     
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  7. Nebraskaorville

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    All great advice guys thank you so much! I do want to bring this system back - it is all stock (original RV2), not converted to 134 and was opened during the engine swap. I will disconnect power to the compressor so it doesn't get engaged. Clutch seems fine and not noisy. I will definitely NOT be adding that ancient oil or any other oil until the full rehab process begins. All the hoses are in really great shape.

    Thanks again!
     
  8. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    So, if you do restore it, I recommend a conversion with R134a. It may not cool as well as conversions of cars in the 80s and 90s, but should still be sufficient. Having done about 8-9 of these, I can state definitively that drawing a vacuum as high as possible for as long as you can, will make a huge difference in how much it cools - getting ALL the moisture and air out before recharge is key.

    I have a 92 Dakota that still had a good R12 charge in 2015, but had to open the system to replace the heater core. I converted it and it cooled well. This winter, the condenser developed 3 separate pinholes and I lost the charge. I replaced the condenser and the hoses, and made sure to draw a vacuum as described above, got nearly 30 inches, and ran it over an hour.
    I can cool beer in that truck. On a recent 90F day, when the truck had been parked all day and was about 120F inside, after less than 10 miles of driving, I had to turn the fan speed down to the lowest of 4 settings. Then I had to adjust the temperature slightly toward the warmer range to avoid being numbed.
     
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  9. valiant67

    valiant67 ...

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    I know it will spoil the originality, but the more modern cylinderical A/C compressor used on 318s starting in 1979/1980 runs better with R134a than the old RV2 compressor.
     
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  10. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    Yes. It may not bolt up right, but definitely works better, and less of a horsepower drain on the engine.
    My 92 Dakota with V-6 has a Sanden compressor that has held up well after 26 years. No noise, no noticeable drag, and it lived in FL its first 12 years.
     
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  11. AllanC

    AllanC Well-Known Member

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    You are referencing the corporate C171 compressor used on R12 refrigerant systems. If the term RUNS BETTER means smoother, less vibration with lower horsepower draw than the RV2 then you are correct. However many indicated that this C171 compressor was marginal in durability when exposed to the higher operating pressures of an R134a refrigeration system. Now many will probably interject they made a C171 conversion to R134a and no problems encountered. If the condenser was adequate in heat exchange and helped keep the higher operating pressures to a minimum then it would work and durability was not an issue.

    Starting in 1991 Chrysler phased in a Denso compressor to replace the C171 on front wheel drive vehicles. It was designed to handle the higher operating pressure.

    On rear wheel drive trucks Chrysler started phasing in Sanden SD 709 compressors in the 1991 model year and abandoned the C171 compressor. This was in anticipation of the change over to R134a refrigerant. The SD 709 is a 7 piston compressor. One way to get a higher refrigerant flow rate and compensate for the lower heat capacity of R134a versus R12 is to add more pistons. The C171 compressor had 3 larger, double acting pistons which equated to a 6 piston compressor. Also your condenser was upgraded and is a dual flow path versus the previous years serial or single flow path. Additional flow paths help increase heat exchange and compensate for lower refrigerant heat capacity.

    I would suggest retaining the RV2 compressor. It is sturdy and will handle the higher operating pressure if you convert the system to R134a. The original condenser was a serial flow / one path flow. You can convert to R134a and check discharge pressure. If discharge pressures get excessively high you may have to retrofit an enhanced flow condenser (one with multiple paths) to get adequate heat exchange lower discharge pressures. But I would try and convert, test and determine operating pressures first.

    One additional point to keep in mind is that Chrysler used an EPR (evaporator pressure regulator) valve at the inlet of the suction line to the compressor. This was designed to maintain a minimum pressure on the evaporator and prevent it from freezing / icing. With R134a and slightly higher suction pressure, this may cause a problem.

    Here is an article that discusses the RV2 compressor.

    Chrysler RV-2 A/C Compressors - Chrysler's two-cylind - Hemmings Motor News (at https://www.hemmings.com/magazine/hmn/2010/03/Chrysler-RV-2-A-C-Compressors/2951871.html )

    Discussion about RV2 EPR valve

    Removing EPR Valves when Converting Your Mopar to 134a | Classic Auto Air - Air Conditioning & Heating for 70’s & Older Cars & Trucks. (at https://www.classicautoair.com/removing-epr-valves-when-converting-your-mopar-to-134a/ )
     
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  12. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    "Also your condenser was upgraded and is a dual flow path versus the previous years serial or single flow path. Additional flow paths help increase heat exchange and compensate for lower refrigerant heat capacity."

    Correct about everything except this. They kept the serpentine condenser in the 1992 Dakota. And the replacement that I just bought is also serpentine. It just happens to be big enough, and the cab of the truck small enough, that it works well.
    My 92 Daytona did have a parallel flow condenser with R12.

    And Chrysler installed a thermocouple into the fins of the evaporator, such that if it gets near freezing, the compressor shuts off.
     
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  13. Nebraskaorville

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    Guys I want to say thanks again. Just got her aligned, lubed and front drums turned. Drives like a dream. New Kellys on used rallys. Looking for beauty rings and center caps. Daily driver. IMG_7078.JPG
     
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  14. Nebraskaorville

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    Hey guys - does anyone know of a clearcoat/plastic/vinyl product i can use on my vinyl top to prevent it from decaying further?
    I dont want to use armour all or whatever because it washes off and streaks down the windows. I'm looking for something like shellac or something just to coat the top - a clear rubber paint or something.

    Thoughts? Thanks in advance!
     
  15. Scrounge

    Scrounge Got parts?

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    Don't know of anything semi-permanent for vinyl. When I had a vinyl top replaced decades ago, the installer said that soft soap and water once per month should keep it clean. You're right about Armor All. The best leather/vinyl conditioner I used is called The Tannery, though I don't know where you'd find that these days. Maguiar's is supposed to give good results. A lot of guys like Mother's products.
     
  16. Nebraskaorville

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    Hey guys, is it me or are these 10" front brake drums with the integrated bearing assemblies made out of unobtainium? I get all kinds of hits for the part but I just see standard drums that are designed to fit over a studded axle. Am I missing something?
    Car is 1972 4-door Valiant with 318, factory AC, non-boosted drum brakes.
     
  17. valiant67

    valiant67 ...

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    As I recall, the bearing hub is pressed into the drum. It may appear as a single piece, but I don't believe it is.
     
  18. ImperialCrown

    ImperialCrown Moderator
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    There are vinyl protectants that contain UV blocker. However, if the car can be sheltered or covered, that is the best protection from the environment.
    The hub can be separated from the drum. It just needs a press. If you are replacing the drums, you don't have to worry about distorting the drums in the press.
     
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  19. Scrounge

    Scrounge Got parts?

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    Do you intend to order the part online? If so, I pretty much see what you experienced. You might instead research your local parts stores, and when you choose one, bring in one old drum to make sure that's what they have.
     
  20. valiant67

    valiant67 ...

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    The local stores all sell the bare drum too.
     
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