A/C repair

[kaycee]

I have all stock A/C in my 69 ,compressor took a dump so am converting to 134. Over the winter I have purchased a sanborn comp. a new drier and I will need a set of hoses. I need to check and see if my poa is good (recalibrate) then I will have a better plan. Or can I replace hoses recalibrate the POA and go on my way. I have read that it would be better with a new parelle flow condensor. Got the compressor all mounted up yesterday and kind of at a fork in the road option now And yes I will pull vacum and oil and etc.

[howzzzit]

First of all is your condenser messed up? If not, run it. You will have to adjust the poa a little for R134a so I read. You don't want the evaporator freezing at low load or low fan. Did you get a new receiver/sight glass? Since your replacing the lines I would blow out the evap and condenser (if using the old one). Regulated nitrogen would do it. If nothing else you could use an air compressor, but you'd get more zip from nitrogen. Blowing it out would help remove any old oil. The old mineral oils will not mix with oil for R134. If there is any residual oil it will be in the evap and condenser.
When you get ready to rock be sure and pull a deep vacuum with good hoses and a/c manifold. Let it set overnight in a vacuum. Check the next day and if it didn't move your golden. If it did you have a leak to find. If you want to get real clean you can do a triple evacuation by repeating this 2 more times. If I were doing it I would break the vacuum with a shot of R134. You don't want air in the system. Moisture is your worst enemy in a system
Make sure you only add the amount of oil the compressor calls for and the right type of oil. Don't know anything about your compressor, but on mine I put the oil in before installing it. Too much oil in a system results in poor performance. I'm still running a Frigidaire compressor and R12. Sometimes in the summer I have to pull over and get out of my truck to get warm.

[Richard]

You can get a new parallel flow condenser pretty cheap, try Ebay. They are much more efficient than the stock one. With 134a there is a need reject more heat. If you do not deal with it, you may be one of the people that says it does not work as well as r12. Another way to improve efficiency of the stock condenser is to seal it to the radiator or at least flush mount to radiator. So at low speed more air is pulled through the condenser instead of around it. Best direction is new condenser and better mounting.

[kaycee]

OK Thanks I got some time to work on it yet ,I have new comp. a new receiver/drier, and expansion valve .Allso Im running an electric fan on the radiator

[kaycee]

Why is my POA rejecting air on testing? I have it all set up like your suppose to took POA off and it is backwords the adjustment screw is on the opposite end it is suppose to be on ,no way to put it on backwords WTF is going on here .

[kaycee]

Here is a pic

[howzzzit]

Is the adjustment in the male end? Here's a you tube maybe help.

https://www.youtube.com/watch?v=mEw5PEBPJYA

[Richard]

Here is a post on calibrating from the forum. http://67-72chevytrucks.com/vboard/s...&highlight=POA Your POA does not look like the one in post or like mine on my 72.

[kaycee]

Yes I saw that post and was hop[ng to do that but the adjustment is on the female side . Must of been swapped from another vehicle

[kaycee]

Well I am going for the newer setup from a square body year 85 no reason just picked it. Should be good to go if I get the accumulator ,expansion valve, evaporator , orifice tube from said year correct. I will get a parallel flow condensor allso. Would I need a clutch switch that goes in the accumaltor or can I block that off.

[Richard]

As the newer system is a cycling clutch type, yes you will need the clutch pressure switch. Cycling the clutch is how the system is kept from freezing as there is no POA. The evaporator is an orifice type, so expansion valve is not used. Always a good idea to install a high/low pressure switch to protect the compressor. The cycling clutch type system was adopted for lower cost by OEM's.

[kaycee]

Ok Thanks for the info how do I wire it in , I thought I read that it was not needed because the orfice tube was being used

[Richard]

The orifice takes the place of the TXV. Any of the pressure switches would just wire in series with the compressor clutch power wire.

[Steeveedee]

What I've seen around the internet is that the A6 compressor doesn't live long if the clutch is cycled. GM must have realized it too, because they implemented the R4 compressor with the CCOT system.

[kaycee]

Not using A6 compressor ,using a sanden 508 THANKS for the info should keep me busy for awhile I'M sure I'll have a bunch of stupid ??

[68 C10 Driver]

Originally Posted by kaycee

Well I am going for the newer setup from a square body year 85 no reason just picked it. Should be good to go if I get the accumulator ,expansion valve, evaporator , orifice tube from said year correct. I will get a parallel flow condensor allso. Would I need a clutch switch that goes in the accumaltor or can I block that off.

Do these run both an expansion valve and orifice tube? I thought it was one or the other.

[68 C10 Driver]

If the compressor is being replaced because the old one burned up, be sure to flush the system out as the acidic oil will cause problems later if you do not.

[Richard]

Originally Posted by 68 C10 Driver

Do these run both an expansion valve and orifice tube? I thought it was one or the other.

See post #13

[kaycee]

Should have condensor here Saturday and the hose kit Monday

[kaycee]

Well ALLMOST got everything in order to hook up Vintage Air hose kit came today . Looked good until I tried to find the fitting that hooks up to my evaporator and none of them hook up .Good thing I was dry fitting the connectors ,I have no clue what size these are on the evaporator.

[kaycee]

Got it allmost ready to button up all I need is to get hoses crimped and reinstalled then a flush and fill . Had to order a #12 x 10 90* fitting for the accumulator to pump connection.

[kaycee]

All buttoned up trying to pull a vacum and I only get about 18 hg or what I would say 18 lbs . How do I find the leak I did take all connectios apart and found a couple of o-rings torn replaced and still only 18 hg . Allso put 5.5 oz of oil in compressor I did find the low press switch was not tight got it tight is there suppose to be an o-ring on this? How do I find the leak

[howzzzit]

Schrader cores tight? If you don't have an electronic refrigerant tester here's the next best way. Use regulated nitrogen and leak detector spray. IMPORTANT! Make sure you use a regulator with nitrogen. Otherwise you can see 2200 lbs or more of pressure. Here's a video explaining the procedure.

https://youtu.be/JaSUDn2VU04

[RustyPile]

Freon leak detectors:
https://www.bing.com/search?q=freon+...ANAB01&PC=LCTS

[Richard]

+1 on the dry nitrogen and leak detector. Have an expensive freon leak detector in my tool arsenal from my past career job. While the sensor type detectors work. Most times they only get you close and still have to resort to pressurizing the system to manually find the leak. They are finicky, air movement causes problems etc. While it may have saved some time on the minor leaks, visual identification was needed most times to pinpoint the leak. While your leak may be at fitting, it may not be.