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Discussion Starter · #1 ·
I have a 71 Chevy truck with factory AC that hasnt worked in years. It's all there but the hoses are bad and the compressor is locked up. I dont care to rip it all out and install vintage air because I want to keep the factory controls and vents. Old Air Products has an upgrade kit that does away with the POA valve, mounts the drier on the evaporator like a later model, and uses a low pressure switch. Is it possible to mod my existing evaporator with parts from say, Napa instead of buying their kit? How would you wire that up? Heres the link to their kit.http://www.oldairproducts.com/catal...Make=Chevrolet&Model=PickupC2FK1030&Year=1971 I'd love to know what that evaporator originally fit.
 

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You can get a high/low switch that plugs into most driers. So that's easy to do yourself.

Basically, that kit changes it form an POA to an orifice tube. But to DIY would be a pain and for that price its all there. Be easy to install then replace your other parts as needed. Then, I would convert it to R134a as well. Which if you did with the POA you might have cooling problems vs R12.
 

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replace the evaporator with one from a 75 or newer truck. it fits in the same plastic box. use 75 hoses and receiver drier as well, this evaporator uses an orfice tube instead of an expansion valve or POA valve and works great . I did this for several customers with great results.
 

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Discussion Starter · #4 ·
replace the evaporator with one from a 75 or newer truck. it fits in the same plastic box. use 75 hoses and receiver drier as well, this evaporator uses an orfice tube instead of an expansion valve or POA valve and works great . I did this for several customers with great results.
Is 75 compressor on driver's side or passenger side of engine?
 

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Is 75 compressor on driver's side or passenger side of engine?
Here is my 68,C-10 with the later(1985 chevy/GMC)evaporator and Ford blue orifice tube(for 134-A).Mentioned by Hotrodg above.
The later evaporator I used is about 3/4" shorter front to back than the original,so I used an extra piece of foam to fill the space.
75 trucks used a Gm a-6 compressor mounted on the passenger side.And R-12 freon.

Mike.:):bowtieb:
 

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It's easy enough to convert the 70s GM pickup a/c systems to R-134. Very easy and cheap to do when you do the rest of the conversion. Costs you about $30 for the conversion fittings.

It looks to me like the oldair conversion is just the same.

As far as the compressor installation, they both use an A-6 GM compressor. A 70-72 truck uses a short water pump and associated brackets, belts, and pulleys. 73-up trucks use a long water pump and the rest. I think the compressor is on the driver side on those. There's no reason to change the 70-72 compressor/brackets unless you have some other reason to do so. Just buy a replacement compressor, and make up the hoses needed if necessary.
 
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