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Complete A/C replacement

  #1  
Old 02-25-2019, 06:59 PM
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Default Complete A/C replacement

Hi all, long time browser first time poster. Anyways a few months ago I picked up a lifted Blazer( pics to my profile to come later) and I made a mistake. I live in AZ and somehow in my excitement for how well the engine ran mechanically I overlooked the fact that it is missing the A/C components in the engine compartment. See attached pictures. Now after having to explain that to the wife, and getting over my frustration and negative attitude towards the individual I purchased the vehicle from, I decided to buckle down and look at what it would take to just replace the system. I've looked into Vintage Air but I think that's a bit pricey, as according to my LMC parts books all the parts i need run under 1k. I just don't have the knowledge or know how to do such a project. Does anyone have a guide on this or am I going to have to start getting quote from local mechanics? any and all advice would be much appreciated. Thank you.




 
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Old 02-25-2019, 09:12 PM
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It basically looks like you're missing 90% of the A/C system and what you do have (the compressor & clutch) will likely need to be replaced.

You will want to make sure that you have all of the electrical connections necessary for the system to operate. You will need the compressor clutch & the pressure cut-off switch connectors. If you have both of those connectors & associated wiring, then you can move ahead with ordering factory replacement parts from where ever you choose (NAPA, LMC Truck, etc) You will basically need all of the lines, an accumulator, compressor w/ clutch, evaporator, orifice tube, condenser, a pressure switch, and the mounts for the condenser. If the lines do not come with new seals, you will need the seals as well.

What is the year of your truck?
 
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Old 02-25-2019, 11:35 PM
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Thanks for the info! My truck is an 87. Guess I need to check a wiring diagram to make sure everything in there.
 
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Old 03-20-2019, 12:15 PM
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Just did a cab forward replacement of everything .... on a '74 though .... compressor came with new engine, its a Sanden style.

Nostalgic AC helped me with the components.

To summarize ....
OEM evaporator .... with an adapter sleeve for orifice tube ....and tube
Accumulator
Custom fitting to go from #12 male to #6 hose (I couldn't find an OEM pressure hose)
Switches and fittings and hoses
New Condenser
I'm bypassing the original temp control switch and using two pressure switches ... so minor wiring change.
 
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Old 03-20-2019, 02:17 PM
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Originally Posted by Semirhagge View Post
Thanks for the info! My truck is an 87. Guess I need to check a wiring diagram to make sure everything in there.
Looks like right about $500 worth of parts on Rock Auto for everything but probably you need to do a conversion for a type of Freon that you can actually still get, and make sure the parts and oil that you buy can use that Freon. That will take more research, but no one uses R12 any more.

Here you go - to convert R12 to R134A in your Blazer. You will need to borrow or rent a vacuum pump and set of gauges from your local auto parts store. System should hold vacuum indefinitely, before you considering adding Freon to it.

1977-Newer Models with Accumulator

The accumulator is most often installed on the evaporator, near the firewall. (Click here for a typical photo)

Minimum Requirements
  • Change or restore the accumulator.
  • Insure that the system is clean and free of contaminants (Depending on component condition, this may be a simple matter of blowing out with compressed air or liquid flushing with an air-conditioning flushing agent)
  • Drain the compressor oil and recharge with 134a compatible (PAG or Ester Oil) oil. This is assuming the compressor is currently functioning correctly.
  • Replace or restore all rubber hoses with barrier hose.
  • Install 134a charge port adapters.
  • Charge with 134a between 70-80% of the original R12 charge amount.
  • Replace any O-rings with 134a compatible.
Recommended:
  • Install hi/lo pressure switch
  • Upgrade the standard orifice-tube to a variable orifice tube.
HELPFUL HINTS
  • Ignore the sight-glass. A properly charged 134a system will likely show bubbles in the sight-glass.
  • Typical 134a charge rate will be approximately 70-80% of the factory R12 charge amount.
 

Last edited by LesMyer; 03-20-2019 at 02:37 PM.
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