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Discussion Starter · #1 ·
Time to Get back to Work on the Wifes Car.I have had enough Yard Work.Here is a Picture where I left off.Cleaning up the Engine Compartment.
Joe
 
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Re: This Place is Slow Guess I will try some Posting

gonna do sumpin' with the heater/ac box too Joe ??? looks kinda tired with the rest all pretty and all....

;)
 

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Discussion Starter · #4 ·
Re: This Place is Slow Guess I will try some Posting

John,
I seached out a Box(that one) that had not been Painted.Those Boxes where left the Raw Glass look as I remember from My A/C Cars.The Camera Made the Box look worse than it is.I cleaned it before Insalling but will Detail it when everything is Done.Still have to make the PAO POA? Valve Work with 134A.New Reciever Dryer and whatnot.My wife is starting to want Her car back together and I cant Blame Her.Things just got in the way.What Started as taking the 406 out to Install a 350 got out of Hand,but what dont.
Joe
 
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Re: This Place is Slow Guess I will try some Posting

ah, ok... i've seen how a camera sometimes fools the eye... looks like ya do quality stuff, so i was wonderin' ;)

yer Honey should be very pleased :D
 

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Discussion Starter · #6 ·
Re: This Place is Slow Guess I will try some Posting

Thanks John,
I thought about Painting the Box,But really am Chasing the Original look.I have something to put on the Box in the end that will make it look uniform,that will help it alot.Just to Old to find a Perfect Box.The Fun will be Getting it to work.When I got the Car All the A/C stuff was Gone.I understand Why,SS and A/C dont seem to Go together but when the Car is Finished I want my Wife to be able to Drive it wherever She wants.No it is Not her Daily Driver.
Joe
 

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Re: This Place is Slow Guess I will try some Posting

134 works with expansion valves, just not with a R12 expansion valve. You have to change it as well as the filter (and once you open it the drier as well).


Big Dave
 

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Re: This Place is Slow Guess I will try some Posting

You lose an average of 10% cooling capacity when you do a R-12 to R134a conversion. This is because your expansion valve is sized for the old R-12 (bigger molecule). The compressor's seals have to be checked thoroughly as the R134a is an escape artist. Same goes for all O-rings at each joint, and because of this all hoses must also be of the SAE barrier type.

The R134 molecule has been around for a long time but was regarded as unsuitable as a practical refrigerant because of its incompatibility with many lubricants. You must not only evacuate all of the R-12 (29 inch vacuum for 30 minutes to get it out of the oil and lines), but you must change the old refrigerant oil out entirely. Using the original refrigerant oil quantity specification, add [INSERT QUANTITY HERE] ounces of Ester oil to the compressor. Ester oil is preferable to PAG in a retrofit, as it will mix fairly well with any remaining mineral oil from the old R12 set-up. Poly Alkyl Glycol (PAG) is a first cousin to brake fluid; and has most of it's negative properties; including being hydroscopic (intolerant of water), having low lubricity, and is incompatible with many types of rubber hose and just chemically unstable.

Replace the orifice tube with the standard "white" GM orifice tube used for many years on many GM models, and the cost is less than $2. (Any parts counter person should know what you mean when you ask for one). There are some newer variable orifice tubes claiming to work better with R134a, but I think it's just a claim, no proof. The white tube restricts the expansion valve (to a degree) and allows it to work with the R134a.

Replace the accumulator-drier with a new R134a compatible unit which contains XH7 or XH9 desiccant. Make sure that you get one with "XH7" or "XH9" dessicant, not "XH5" -- there should be a sticker on it stating as such. XH7/9 works just fine with R12 and is necessary with R134's Ester or PAG oils. As a cross-reference, a 1986 Corvette accumulator-drier is perfect. Factory Air brand part number 33191 dryer is ideal, and runs about $55 at AutoZone.

Replace any O-rings on the receiver-drier or accumulator-drier joints; check and replace other O-rings that have been disturbed. You really should replace them with the new green ones -- they work very well for both R12 and R134a.

Disable the R-12 service fittings to prevent any refrigerant other than R134a from being used. You do this by permanently installing R134a quick-connect service fittings to the A/C system.

Charge the A/C system with R134a. Generally, about 5% (by weight) less than the R-12 charge amount is required.

Once the above has been done you shouldn't have any complaints with R134a.


Larger Dave
 

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Re: This Place is Slow Guess I will try some Posting

Thanks again Dave. I have a quart of oil left over from conversions I did on 2 79 models I'll check the type. I didn't realize the El Camino had an orifice tube. I am running a Sanden (I think) compressor with AN fittings and steel braid hoses. I'll have to check which type of O rings were used in the system.
 

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Discussion Starter · #12 ·
Re: This Place is Slow Guess I will try some Posting

Philip,
Thanks for the info.I did some Checking on the Ststem before picking the Stock System,My Brother lives in Florida and they service alot of A/C Systems down there.I also talked with a Company there that Sells both Aftermarket Systems and Replacment Parts for Original.Most Info leads to replacing accumulator-drier and Recalibrating the PAO Valve.
Big Dave,
Thanks for that Info also,I Printed it.I need all the Help I can get when it Comes to A/C.My Knowledge with A/C is in Replacing Condensors and Evac. and Recharge,in other words Collision Related.
Joe
 

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Discussion Starter · #13 ·
Re: This Place is Slow Guess I will try some Posting

Dave,
I see you are in Florida?
Joe
 

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Re: This Place is Slow Guess I will try some Posting

A day with out A/C in Florida is like a day being staked out in the Sahara (same latitudes just North of the equator). You can not give away a car without A/C.


Bid Dave
 
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