Reinstalling A/C

[Scott2.0]

Hey guys, I'm looking at a '78 C10 and the owner said he threw away the AC compressor when rebuilding the motor and never replaced it. Should adding AC back to it be as simple as replacing the AC compressor? Sorry, I really have no idea what I'm getting into here. Thanks.

[Liberty]

Probably not.

With the compressor gone the system has been left open for an unknown ammount of time. Chances are there is significant contamination in the A/C componants, plus it is unlikely that the system was upgraded to take R-134.

On my truck it was $1,500 to redo and upgrade the A/C.
A strong word to the wise, DO NOT get a remanufactured R4 "pancake" compressor. They are total junk and likely won't last a year. Mine certainly didn't, so be sure they put a brand new compressor in.

[Scott2.0]

Originally Posted by Liberty

Probably not.

With the compressor gone the system has been left open for an unknown ammount of time. Chances are there is significant contamination in the A/C componants, plus it is unlikely that the system was upgraded to take R-134.

On my truck it was $1,500 to redo and upgrade the A/C.
A strong word to the wise, DO NOT get a remanufactured R4 "pancake" compressor. They are total junk and likely won't last a year. Mine certainly didn't, so be sure they put a brand new compressor in.

Thanks for the information, that's exactly what I needed to know. I didn't think about contamination of the components at all. For $1500 I'd have to pass on this truck.

[Liberty]

Originally Posted by Scott2.0

Thanks for the information, that's exactly what I needed to know. I didn't think about contamination of the components at all. For $1500 I'd have to pass on this truck.

There could be, there might not be. That being said, most A/C shops wouldn't touch it if you didn't agree to replace the rest of the system, plus you run the risk of killing the new compressor.

Didn't mean to scare you off from getting the truck! Pending on the condition of the rest of it and the asking price, I'd still be interested. Plus non working A/C would be a great price negotiator.

On these old Trucks the A/C is usually dead anyway, and if it isn't it will be soon unless it has already been upgraded or atleast serviced with new parts. So I wouldn't let a dead A/C deter you.

[Scott2.0]

Originally Posted by Liberty

There could be, there might not be. That being said, most A/C shops wouldn't touch it if you didn't agree to replace the rest of the system, plus you run the risk of killing the new compressor.

Didn't mean to scare you off from getting the truck! Pending on the condition of the rest of it and the asking price, I'd still be interested. Plus non working A/C would be a great price negotiator.

On these old Trucks the A/C is usually dead anyway, and if it isn't it will be soon unless it has already been upgraded or atleast serviced with new parts. So I wouldn't let a dead A/C deter you.

Here in AZ, it is a must and the guy already told me he's firm on his price which isn't really reflective of it not having AC. Thanks again though!

[rich weyand]

You can get a completely new Vintage Air kit (#944175, for 1973-80 w/factory air) for under $1300. That's all the brackets and the condenser and the air box etcetcetc, minus the dash plumbing (already there on a factory air truck). It also gets rid of the big box sticking out of the firewall.

[Jeepwm69]

One of my 85 Jeeps was missing the condensor unit when I got it, and by the look of things, it had been gone for quite awhile. I bought a used one off of ebay (risky) and had a new compressor to condensor hose made, and hooked it up, and changed it with R134. Would freeze me out for the first few years until I got a pin hole in the condensor. Have a replacement, but haven't gotten around to putting it on yet.

Point being, while contamination MAY have junked the AC system, it might not have. Unless you find one with working AC (which is rare these days on the squares) you might have little to do, or it might take a total replacement.

I wouldn't let the AC system deter you if that's the ONLY thing keeping you from buying a truck.

As Rich says, a whole new system isn't that much money. Lot cheaper than a lot of other potential problems you might find in a 30 year old vehicle.

[Liberty]

I gotta firmly agree with Rich and Jeep on this.

For me most of the 1,500 was labor. Looking back I very likely overpaid.
What I would do is look at those vintage air units and call shops in your area to give you a better idea on the cost of repair or replacement.

[Scott2.0]

I agree with you guys if it is reflected in the price. The truck in question is going for $5500 firm and it needs some minor body and interior work. To me, there is no value in it if I also have to put in A/C. It would be like selling a truck in the north without heat and not having that reflected in the asking price. Thanks for the info, guys.

[Liberty]

Oh yea 5,500 is a bit much if it needs that kind of work.

[RUN GMC]

Rockauto has R134 A/C kits for under $200.00(compressor, receiver drier/accumulator, & oriface tube), evaporator core $76.00, condenser $85.00(3 choices under $85), and hoses $90......it took only under 300.00 to restore my a/c in mine because I didnt just want to swap refridgerant.....I got the a/c kit and hoses......had a i/c tech at work pull the vacuum on it......just another option for you......

[Chaplain]

Originally Posted by RUN GMC

Rockauto has R134 A/C kits for under $200.00(compressor, receiver drier/accumulator, & oriface tube), evaporator core $76.00, condenser $85.00(3 choices under $85), and hoses $90......it took only under 300.00 to restore my a/c in mine because I didnt just want to swap refridgerant.....I got the a/c kit and hoses......had a i/c tech at work pull the vacuum on it......just another option for you......

Good info. Thanks

[ZacharyDouglas1992]

x2 what RUN GMC said. I got my parts from local stores, so probably had 500 in it, but still not bad. Replacing it all is definitely a good way to go, it hits up to 110 here in the summer.

Avoid any of the pancake style r4 compressors made my 4 seasons. They have a horrid seal failure problem. And definitely don't get a remanufactured compressor. They are DOA

[Titomars]

Well as it has been said the cost can be high or it might not be. what you will definitely need is a compressor new or rebuilt, an accumulator and an orifice. You will probably also need some if not all the brackets to mount the compressor. Also possibly the hose and manifold assembly to the compressor.
Best case scenario you need a compressor, accumulator, orifice, new orings everywhere, at least 1 flush kit, oil, and some R12.

Now without pictures. I will paint the picture of what has probably been done to it. The truck was running warm to hot in the Arizona summers. So the owner basically cut the A/C system out. removed the compressor, brackets, hoses, condenser, and accumulator. because he did not have the proper wrenches he most likely hack sawed the fittings off at the evaporator rendering that part junk too. I lived 10 years in Las Vegas and seen the scenario many times. Like I said with out photos I can't give you any idea what it would cost.
If you are serious about the truck and want an idea, get some photos of the engine compartment and we shall see. I am a retired mechanic and an A/C electrical specialist.

[hatzie]

I believe 1978 is still the TXV system with the big long Harrison A6 compressor not orifice tube with the R4 Radial... but I reserve the right to be wrong.
If it's been open you'd be well off to update it to the later Orifice tube system. Usually you can salvage an open Evaporator by flushing and pressure testing but the condenser and hoses are probably pretty much unserviceable at this point.
Vintage air will get you a modern Sanden compressor, the right hoses, a good condenser, and a complete heater/evaporator box that fits inside the cab. If I had it to do over I'd probably go that route with my 76. The big Evaporator box wouldn't be protruding into the engine compartment so I could probably fit the 6.5L turbo from a T400 chassis truck on it. The Banks turbo kit I have cost almost double what a Vintage air kit would cost.
$5500 is too much for a truck with dead AC and mildly damaged interior.

[truckin 79]

You can buy some AC flush from any parts store for like 20.00, I used 2 cans not on a truck but a car. So flush both condesor and evaporator and then chase with conpressed air. If you are trying to switch to R-134a then the rubber hoses should be changed. You can still find places that will fill AC with R-12. I bought a AC compressor from Napa for 250, 1 year warranty. Need a orifice tube like others have said. Once you have flushed everything and hooked compressor back up have someone pull vacuum on the system. You can buy a vacuum motor from harbor freight or even a small little pump you hook up to compressed air. It is probably easier to take to to a AC shop and have them pull vacuum and if it holds they will fill with refridgerent. Oh I almost forgot you have to replace receiver/dryer as well usually 50.00. If most parts are there in truck then it can be done for around 500-700. You tube has tons of videos on this.

[hatzie]

My prior post is correct There is no Orifice Tube on stock 1973-1981 trucks A/C systems unless the Evaporator core and accumulator has been replaced with a 1982-1991 setup. 1978 still used the big heavy Harrison Frigidaire A6 compressor as well.

The stock 1973-1981 AC systems use a Thermostatic Expansion Valve TXV rather than an orifice tube to control the pressure drop across the evaporator.
Just FYI the rear air evaporator units in Suburban, G vans, and Motor home chassis still used a TXV much later than 1982.