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#1 |
Senior Member
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Location: Cypress, TX
Posts: 3,702
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Factory A/C, what to do
Folks, assume I know very little about A/C. I am able to understand mechanical things but an A/C novice and I have no tools related to A/C. What I have here is a 1969 CST/10 with A/C, and so far I have not done anything with the A/C. When I pulled the engine and fixed it up, I just unbolted the compressor and set it aside and left the hoses attached. The whole A/C system looks pretty much undisturbed although dirty, and the only things I see obviously wrong are the control panel has broken levers and the A/C clutch wire is chewed up, and the inside duct work has been re-routed in weird ways to accommodate a larger than stock radio.
So, here are my questions: Should I keep the hoses attached and fix and clean around the system assuming it is still pressurized? If I can get the controls, wiring, and blower motor and other such things working, I would then have the R-12 topped off and install a belt on the compressor and see what I get when I start it up. Would that be worth the trouble, or should I go ahead and completely disassemble right from the start? |
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#2 |
Registered User
Join Date: Nov 2014
Location: Bigfork, Montana
Posts: 1,137
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Re: Factory A/C, what to do
The system has probably leaked down over the years but, maybe not. If you have access to a set of gauges you can check for pressure. If you are going to do the work yourself you need a set of gauges anyway. Static pressure on a fully charged system should be around 80-100 psi. (someone here may have a more exact #) If it's low or at zero then go ahead & disassemble. If it's at, or close to full charge then leave it together & try it.
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#3 |
Registered User
Join Date: Feb 2012
Location: Smyrna TN
Posts: 1,153
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Re: Factory A/C, what to do
I just went through this with my truck. I did a lot of research before I started. Just a few things to consider; wear safety glasses as a shot of freon in the eyes can blind you, never open the high side gauge while recharging as the pressure from the compressor will feed back through the small can you're holding in your hand (dangerous), understand the difference in low pressure side and high pressure side, and its illegal to purge freon into the open air. Gauges are a must, you can get them from AutoZone as a loaner tool. YouTube has several videos on servicing A/C I found useful. There are lots of threads on this board to help in your decision to keep original or replace with Vintage Air.
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1971 Longbed BB Cheyenne Super 1972 Longbed SB Cheyenne Super 1972 Longbed Highlander Custom Deluxe 1975 K5 4x4 full convertible Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=645165 Greg Smyrna TN |
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#4 |
Registered User
Join Date: Jul 2014
Location: Humboldt,Sask.
Posts: 42
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Re: Factory A/C, what to do
Press in on one of the Schrader valves with a screw driver and you'll be able to tell if it still has any pressure. Then turn the front hub of the compressor by hand to see if it still turns this hub is connected to the pistons. More importantly figure out how the wiring functions and get the controls and cables working. An a/C mechanic can test and recharge the system. Good luck.
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1972 Cheyenne Longhorn k20, 402, A/C |
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#5 |
Registered User
Join Date: Aug 2006
Location: Redmond, WA
Posts: 6,332
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Re: Factory A/C, what to do
Presuming it's discharged and you want to get it ready for charging:
If you're going to do it yourself, you'll need the following: Some kind of vacuum pump: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1 Manifold Gauge Set: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1 Then you get the system all set up, hook up the manifold gauges, run the vacuum pump to pull a full vacuum on the system, and see if it'll hold it overnight. If it does, then you go somewhere and get it charged up. If not, you find and fix the leak, and repeat the process until it holds a vacuum overnight. Since you'll have about $200 in tools to get that far, sometimes it's false economy doing it yourself and you should just take it somewhere that services AC. I wound up doing both, as my compressor leaked out the first fill I had... it only held vacuum for about 6 hours, which I convinced myself was "adequate", but it wasn't.
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1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible |
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#6 |
Registered User
Join Date: Jun 2014
Location: Ingleside, IL
Posts: 56
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Re: Factory A/C, what to do
If your system is flat, then looking for leaks with a dry gas (nitrogen) under pressure is the best method. Do not use compressed air as the moisture level will cause you great pain. Leaks occur at all the usual places, compressor shaft, mechanical connections, and especially the evaporator since this is where dramatic changes in temperature occur. Get the system tight before evacuating or charging and you will be a happy camper.
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#7 |
Registered User
Join Date: Jan 2000
Location: Wyoming USA
Posts: 2,445
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Re: Factory A/C, what to do
I did the same as you, I replaced all the vent tubes and such back to stock inside cab, traced all wires and hoses, brackets and got them hooked up and looking good for my taste. My compressor was good ,new drier and O-rings a 12 pack of bud light and off to my buddy's to recharge been holding good for a couple months now. He knew what oils and such to do so I'm not going to ask I am going to take him another 12 pack this afternoon .He did put 134 in though. I do live in Wyoming so the week we get into the 90/100 will be nice to have
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2001 Silverado K-1500 2005 FXDWG stage3 69 CHEVY Short/Step 327/4L60 373 posi 63 IMPALA 327 |
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#8 |
Senior Member
![]() Join Date: Apr 2016
Location: Cypress, TX
Posts: 3,702
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Re: Factory A/C, what to do
Thanks very much for all the information folks. This is the sort of thing I was hoping for in this post. If you vacuum and it leaks, how do you find the leak? Do you pressurize with air using some sort of pump?
EDIT I was writing while SJLenz1340 was writing. So where do you get nitrogen and is a pump required for that? |
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#9 | |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,392
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Re: Factory A/C, what to do
Quote:
You won't need a pump, but you will need a regulator to reduce the pressure from the tank. You will then need an ultraviolet light to find where the leak is. #1 leak is from the front seal of the compressor. If you see an oil streak running across the underside of the hood, in line with your AC compressor clutch, it's the culprit.
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#10 |
70+ ( Old Skool Club )
![]() Join Date: Nov 2003
Location: Saskatoon, Saskatchewan ,Canada
Posts: 9,117
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Re: Factory A/C, what to do
Or, you can take it to a professional A/C shop and let them deal with it. Then you can enjoy nice A/C throughout the hot summer. I've done a lot of things to my trucks over the years and was reluctant to try them and oh so pround of myself after I did them and everything worked as it should. My feelings are there are lots of things we can do to our trucks but I like to leave what I call "specialty " work like trans rebuilds, engine overhauls and rear end and A/C work to the pros.
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1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021 |
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#11 | |
Senior Member
![]() Join Date: Apr 2016
Location: Cypress, TX
Posts: 3,702
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Re: Factory A/C, what to do
Quote:
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#12 | |
Senior Member
![]() Join Date: Apr 2016
Location: Cypress, TX
Posts: 3,702
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Re: Factory A/C, what to do
Quote:
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#13 |
Senior Member
![]() Join Date: Aug 2004
Location: Centennial, CO
Posts: 2,946
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Re: Factory A/C, what to do
Since you're wanting it to work correctly, go thru all the under dash stuff and fix/rebuild as necessary. It all gets worn out and it will work way better if you have all the ducting right.
I had a factory a/c truck when I lived in DFW and it was night and day after I repaired all the ducting. It's not too complicated or expensive.
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ClusterTruck: 68 C10 Bought in 89, wrecked in 03. Slow low $ rebuild started '17. 6.0 & TKO http://67-72chevytrucks.com/vboard/s...d.php?t=788602 93 K1500 Short Step, 350, NV4500, EBL flash ECU. Vortec heads & roller cam someday... 05 Jeep Wrangler Unlimited. 3” lift & 6-speed 02 E320 the insurance total “free car” 13 Tahoe LTZ |
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#14 |
Registered User
Join Date: Apr 2007
Location: pasadena,TEXAS
Posts: 880
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Re: Factory A/C, what to do
There's a guy near you in ft. Worth that refurbishes and knows about old ac's. he refurbed mine and it looks great and has some great info. He goes by F A A Benny here on the forum and on Facebook..... look him up!
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1971 Cheyenne SWB 402BB, 700R4, 3.73 posi, PS, PB, A/C, Tilt, Tach "Wanda" Don't argue with idiots, People watching may not be able to tell the difference... There's someone in my head........But it's not me...... cheap tricks thread great info here!! http://67-72chevytrucks.com/vboard/s...d.php?t=489394 |
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#15 |
Senior Member
![]() Join Date: Apr 2016
Location: Cypress, TX
Posts: 3,702
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Re: Factory A/C, what to do
That is a beautiful engine compartment. Did you leave it to him from beginning to end, drop off your truck and pick it up later with working A/C, or did you do some of the work yourself?
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#16 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,392
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Re: Factory A/C, what to do
That would be better than dropping a pile of cash on the tank, regulator, etc. I only posted so that you would have an idea of what to do. It gets expensive fast. I have gauges and a vacuum pump because I bought an AC service machine from the shop I used to work at when the owner died.
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#17 | |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,392
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Re: Factory A/C, what to do
Quote:
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#18 |
Registered User
Join Date: Apr 2011
Location: formerly NY currentlyNC
Posts: 389
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Re: Factory A/C, what to do
a vacuum pump is also available from autozone as a loaner
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1970 short step c10 leaf spring 454 |
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#19 |
Senior Member
![]() Join Date: May 2012
Location: Scottsdale, AZ
Posts: 1,906
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Re: Factory A/C, what to do
Hey, how is your compressor wired? I noticed the two prongs are not connected.
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White K20 |
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#20 |
Registered User
Join Date: Apr 2007
Location: pasadena,TEXAS
Posts: 880
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Re: Factory A/C, what to do
Thanks... I pulled the the evaporator/fan piece and the heater box and sent them to benny to be refurbished and checked because I live outside of Houston 4 hours from fort worth. He refurbed the boxes , checked and replaced the fan and evaporator, checked the expansion valve and poa, and knew of a place that could recore my original heater core. I installed it all including new hoses, condenser and rebuilt compressor. his work look great! everything went back together and looks great but I think the rebuilt compressor isn't working right so I need to check it out.
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1971 Cheyenne SWB 402BB, 700R4, 3.73 posi, PS, PB, A/C, Tilt, Tach "Wanda" Don't argue with idiots, People watching may not be able to tell the difference... There's someone in my head........But it's not me...... cheap tricks thread great info here!! http://67-72chevytrucks.com/vboard/s...d.php?t=489394 |
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#21 |
Registered User
Join Date: Apr 2007
Location: pasadena,TEXAS
Posts: 880
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Re: Factory A/C, what to do
that pic was from when I got it all together but had not squirted the R12 in it yet so I had the compressor unplugged to prevent a ut-oh. heres another one during install to check the wire length
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1971 Cheyenne SWB 402BB, 700R4, 3.73 posi, PS, PB, A/C, Tilt, Tach "Wanda" Don't argue with idiots, People watching may not be able to tell the difference... There's someone in my head........But it's not me...... cheap tricks thread great info here!! http://67-72chevytrucks.com/vboard/s...d.php?t=489394 |
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#22 | |
Senior Member
![]() Join Date: May 2012
Location: Scottsdale, AZ
Posts: 1,906
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Re: Factory A/C, what to do
Quote:
Nice engine bay. Mine is uglier than me.... ![]()
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White K20 |
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#23 | |
Registered User
Join Date: Apr 2007
Location: pasadena,TEXAS
Posts: 880
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Re: Factory A/C, what to do
Quote:
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1971 Cheyenne SWB 402BB, 700R4, 3.73 posi, PS, PB, A/C, Tilt, Tach "Wanda" Don't argue with idiots, People watching may not be able to tell the difference... There's someone in my head........But it's not me...... cheap tricks thread great info here!! http://67-72chevytrucks.com/vboard/s...d.php?t=489394 |
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#24 |
Senior Member
![]() Join Date: May 2012
Location: Scottsdale, AZ
Posts: 1,906
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Re: Factory A/C, what to do
Ya, after all that effort you want cold, especially if you used the r12. A loose belt will make you think the pulley is locking up, but it's the belt not gripping. Tighten the belt. I would seriously consider getting an evacuation and charge from a pro. I do my own, but I can hang with 50s, our heat here is pretty dry. Anything under 90 and I'm happy to just roll down the windows anyway. I am considering a proper oiling and evacuation from a good shop. I just replaced my compressor(and nothing else) with a dirt cheep A6 and did my own hokey evacuation and roughly speaking oiling, then charged with cheap wally world 134a (not sure if there is a quality difference in brands)... and I am getting low 50s at the vent. So, you should be able to do better for sure.
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White K20 |
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#25 |
Moderator
![]() Join Date: May 2007
Location: Southern Cal
Posts: 20,005
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Re: Factory A/C, what to do
The a6 compressor does not cycle, it's either on or off.
The a6 will "lock up" and act like it's hard to turn, and your belt will squeal like a pig. I went through 4 of them over the years on various trucks before I concluded I was wasting my time and went with a new aluminum a-10. No more belt squeals, no leaks, no problems. A rebuilt a-6 will fail, it's only a matter of time. They also leak at the front seal. I will never use one again unless it's the original one on the truck from the 70's and still functioning. I restored the factory AC in my 68 a few weeks ago, a-10 compressor and r-12. 36 degree air idling at a stop light in 100 degree heat without missing a beat.
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1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man |
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