I'm wanting to put the factory installed A/C stuff back in my truck now after being with out it for 3 years. I took it all out because it didn't blow cold anyway, didn't know why and wasn't worried about it at the time. I still have the compressor, but like a big D A I threw out the evaporator core, hoses, condenser, and dryer. All of the wiring is still in place along with the big box under the hood, because I kept the heater. I was looking online and it looks like the evaporator is going to be the most expensive piece to replace. Now after all of that, is an evaporator core a safe piece to get from the junkyard? Or do they tend to be what goes bad in the factory A/C system. For that matter are condensers usually ok from the junkyard too? I don't want to go to all the trouble of pulling one or both out of a junker just for them to be bad. Thanks for any insight in this guys. I guess this might help, this is for my 77 F100 with 302 with factory installed air.

 

I believe that most junkyards warranty their parts for 30 days, or at least the ones I've been to do that. I've purchased a radiator before for my old Chevy van and it was just fine. The place I went had all the radiators, evaps, condensers stored in a big semi trailer out in the yard.

 

Quite true 2000, but 70's ford trucks aren't as common in the yards as they used to be (at least in my area). Warranty or no, they may not have a replacement to give you if it fails. Especially AC parts, as that was a fairly uncommon option. The Scrap pool for 70s AC trucks is getting shallower every day. I had that happen on an oddball part for my 85 Lincoln Mark VII. They couldn't find a replacement so they refunded my money.

jsutton,
I would normally advise against used AC parts in general. It's usually a real crapshoot and not worth the bother. Your evap is expensive and there are probably a lot of servicable used parts still out there, though. In another 5-10 years, probably not.Most 60's and early70's vehicles I see have corroded evaporators, no used ones can be found.

Evaporators on those 70s trucks were never failure prone. The newest ones will be 30 years old, though, and things can get s***ty just from age. Ideally, you would remove one from a pressurized, working '79 system, but...yeah.
Look for an evaporator core from a later truck, I don't think they changed from 73 to 79. Check the new pat listings to be sure.

Inspect the outside for old oil stains or oily dirt caked on. Also look for visible corrosion. The lack of those is a good sign. Loose dry dirt, dried caked mud and debris is to be expected. Look for smashed or flattened fins, the fewer the better.
If the yard will let you, blow through the core with compressed air and catch the output on a white rag or paper towel. If you see any sign of white dust (corrosion) blowing out, pass on the part. Dirty or milky oil or chunks of debris is bad, pass. If you get clean air or clean oil and air, that's a really good sign. If the yard can't oblige, check it when you get home.(assuming you have a compressor or access to one.)

Once you get it home, immerse the core in a Dawn dishsoap and water solution and pressurize it to 30-40 psi. (Gently mix the soap into the water to prevent foaming) Watch closely for bubbles that would indicate a leak. Gently slosh it around first to dislodge air bubbles trapped in the fins, those can make you think there is a leak as they float out. You can go as high as 100psi without fear, but 30-40 should be fine.
If it passes, agitate it a bunch to clean it, then rinse with clean water (outside only) and blow it dry. You'll be amazed at the crud that will come from the outside of an evap core!
Also closely inspect the fittings and seal areas for dings or damage from storage. Pay attention to any threaded fittings.

If it passes all of these tests, it's probably good to go. Solvent flush the core (inside) and cap the tubes until you connect the lines. Green painters tape is fine for capping.

Oh! All of the above applies to the condenser too. Water testing is much harder, but they are much easier to visually inspect. No oil spots or caked on oily dirt, probably good. You can likely skip the soapy water test.

The shaft seal in your old York compressor is probably bad after all this time on the shelf. The crankcase is also full of (R12) mineral oil. Post back when you get to that point and we'll figure out what to do. Be aware that you might have to replace the compressor with a reman unit. A good quality reman York is about $300-350. (the cheaper remans from the "chain stores" are of very questionable quality) Budget for that much and then be pleasantly surprised if the old one can be reused or resealed.

I don't know if you've ever seen a 73-79 Truck AC system working properly. If not, you'll be really glad you spent the money to fix yours. If you can source R12 for it, that's the best. Those systems convert well to R134a, though. There's some tweaking involved.

Hope this helps.

 

Good advice! Evaps generally don't go bad, but it does happen rarely, like everything. Do the pressure check and other inspections as advised and if so, then you have a winner.

-Dave

 

Yes, I've seen the factory installed A/C work in these trucks before. The one that was in the this truck used to work. But by the time I got it back from my dad in about 1999 or so, it had quit blowing cold. That's one reason I decided the ditch it. Wish I would've just seen why it wasn't blowing cold and fixed it then. The compressor still turns freely and I can feel it moving air when I spin the pulley by hand. As far as the condenser goes, I was gonna buy that new, the only piece I was gonna get from the JY was the evaporator, because of the price of a new one. A condenser is only about $130 from Autozone and a drier is only about $20. Hopefully my compressor is okay. They have a few dentsides at the U-Auto-Pull-It, so maybe one of them will still be charged up and if so I may yank everything from that truck. Thanks for the insight I'll let ya'll know what I find.

 

What's the deal with the evaporator costing so much for these trucks. I was looking at E-bay again and for my truck the evaporator is almost $300, but for the 80's and 90's trucks they are only like $75! WTH??

 

Okay, as I stated in my other post I plan on trying to make it out to the JY tomorrow. What is the best way to see if the system on a particular truck is still pressurized? Hook a A/C manifold gauge up to it, I'm guessing? Are there any other ways? Thanks.

 

I took some pics of my compressor. I tested the clutch a few minutes ago by grounding the body and hooking the turn on to a positive 12 volts and it clicked and engaged everytime. So I'm guessing my clutch is okay. So if I do have to buy a new compressor I can get one without a clutch. Any way what are the two things under the thin caps on the ends of the hoses? Pic 1 is with the caps on and then they are off in pic 2 and 3 one side is rusty and the other side is nice and clean? Sorry for so many questions, but the more I think about this the more I want to learn and get it done! Thanks.

EDIT: The date on the pics are wrong I just took them today. I painted the compressor a few years ago before I put it on the shelf.

 

The access valve stems for the lo and hi side are under the caps. There should be square headed shafts that open and close the schrader ports that are under the hex-headed caps that are also on the same block as the valve. You can close them to lock out the compressor or you can open them up to allow access to the service ports and normal operation, if memory serves. Verify they work before you start to do any vacuuming or charging. If there are schrader (tire valve stem) valves inside the caps, I think you may have to replace them if you plan on changing your oil from mineral to ester using R134a. I have a half memory that the 'rubber' does not like ester or pag.
tom

 

To expand on tomw's excellent response a bit:
-Those valve are called Roto-Lock valves.
-The normal running position for those valves is seated Fully Out, or Back Seated.
-To open the service ports to the system, you turn them IN about 1-1.5 turns or Crack Seated.
-To isolate the compressor from the system, you would turn the valves Fully In, or Front Seated. NEVER run the compressor with the High side valve Front Seated! It will blow the head off of the compressor. It is possible to close the Low side valve and pump down the compressor then close the high side valve to store the entire system charge in the system and remove the compressor for service.

Always use the correct wrench on the valve stems! Using an open end wrench or (yeech!) channel Locks or Vise grips WILL damage them. Here's the wrench: http://www.acpartsandsupply.com/tls-h24-127.html
Your local NAPA store should have it or can get it..

 

Apparently at some point in time, I don't when it would have been because my dad has had this truck since 84 and he never had anything done to the A/C. Anyway some one got after the one that is rusty with some vice grips because it is completely rounded off! So I'll be getting new valves, or at least one I guess, unless I yank some from the JY too. Thanks for the info.

 

IIRC, there were a few different style valves over the years from about 1955 to 1979. If you stick to 73-79 Trucks, I don't think you will go wrong. When you replace the valves, make sure to replace the seal between the valve and the compressor. Don't try to reuse the old ones.

Darn I feel old. I remember when you couldn't take 5 steps in a junkyard and not trip over one of those York compressors with the stem caps intact and never been touched. Even now my mind says "Aw, those things are all over the place like cockroaches. Just grab two or three from the junkyard...".
Ford hasn't used them in 30 years!!! Noooo...

 

Well the JY only had 5 dentsides and only three of those had factory air. None of those three had compressors, condensors, or driers. Only one still had the evaporator in place but no hoses hooked to it. I looked at it through the blend door in the bottom of the housing and it didn't have hardly any rust on it and it didn't have any dirt on it. I'm going to go back to get it next Friday morning, didn't have time this morning.

 

I know I'm running this thread crazy, but like I said I'm trying to get all the info I can. I found this on E-bay. It's made by General Motors, brand AC/Delco, I thought that was strange. The price is pretty awesome too, much better than the $300 I saw last week.

http://cgi.ebay.com/ebaymotors/15-63...171|240%3A1318

On a side note I'm glad I didn't have time to yank that evaporator Saturday, because I just found out they are having a 1/2 price sale Friday!! So I'm gonna go get it for $8! And if it doesn't work I'm not out much.

 

That's a good price on the new Evap.
AC Delco parts division is not owned by GM anymore, but they're decent offshore stuff. I'm thinking they're part of Honeywell maybe?

For $8 for the used one, you'd be silly not to try it.

Good Luck