What do you replace mostly when fixing A/C - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Luis_gz06 · 04-08-2008, 12:15 AM

What parts do you guys replace mostly when fixing stock A/C to get it working properly? Ive replaced drier, expansion valve, compressor and recharged it and nothing good yet. The bad part is that im trying to fix it myself. I haven't vacumed it like it should, I just hooked everything up, and put refrigererant. But my main ?? is, what parts have to be replaced most of the time? Thanks!

stope4 · 04-08-2008, 12:52 AM

does compressor come on when you turn it on? Does the fan work on low, medium, high? what year truck. Got to give people more info.

**leddzepp** · 04-08-2008, 12:54 AM

You really need to put a vacuum on it for about 20-30 mins to properly evacuate the system. That is probably your problem right there. A/C sounds real simple, but in actuality it is not. Are you using R134 or R12? If converting to R134, the system needs to be flushed (not just evacuated) Any moisture in the system and it will NOT work, hence the vacuum. Most A/C parts do not fail, except the compressor. Did you put PAG 150 oil in the compressor yet? The other part that fails sometimes is the original POA valve. If you still have the original POA valve, it is important to NOT introduce oil when re-charging. In other words, do not buy freon that has oil added to it. I have completely restored the A/C in my 72 and it blows ICE cold air. Any other questions, feel free to PM me.

**john** · 04-08-2008, 01:13 AM

[QUOTE= I haven't vacumed it like it should, QUOTE]

That is your problem. Pulling vacuum not only removes all of the moisture, and it lets you know if there are any leaks. If your new dryer is exposed to atmosphere for very long it will also be contaminated with moisture.

Luis_gz06 · 04-08-2008, 11:51 PM

Thanks everyone! I am using r134 refrigererant. Compressor is new, fan works in all 3 speeds, and its a 70 truck.

**leddzepp** · 04-09-2008, 01:14 AM

Too bad you are not in So Calif...I'd have you cruise over and take a look at it. I have all the tools to do A/C now.

69heavychevy · 04-09-2008, 02:21 AM

yea be sure to vacumm, if not you can kiss your new compressor good bye in a few months. dont forget the condensor, very important component and often overlooked. dont know if this older trucks had evaporators but thats also something too look at if equipped with. good luck!

04-08-2008, 12:15 AM	#1
Luis_gz06 Senior Member Join Date: Feb 2006 Location: Las Vegas Posts: 1,378	What do you replace mostly when fixing A/C What parts do you guys replace mostly when fixing stock A/C to get it working properly? Ive replaced drier, expansion valve, compressor and recharged it and nothing good yet. The bad part is that im trying to fix it myself. I haven't vacumed it like it should, I just hooked everything up, and put refrigererant. But my main ?? is, what parts have to be replaced most of the time? Thanks! __________________ 1972 Chevrolet Blazer 4x4 (Almost done stay tuned) 1970 Chevrolet Pickup Longhorn CST/20 (SOLD)

04-08-2008, 12:52 AM	#2
stope4 Registered User Join Date: Jan 2006 Location: Houston Posts: 434	Re: What do you replace mostly when fixing A/C does compressor come on when you turn it on? Does the fan work on low, medium, high? what year truck. Got to give people more info. Last edited by stope4; 04-08-2008 at 12:52 AM.

04-08-2008, 12:54 AM	#3
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,996	Re: What do you replace mostly when fixing A/C You really need to put a vacuum on it for about 20-30 mins to properly evacuate the system. That is probably your problem right there. A/C sounds real simple, but in actuality it is not. Are you using R134 or R12? If converting to R134, the system needs to be flushed (not just evacuated) Any moisture in the system and it will NOT work, hence the vacuum. Most A/C parts do not fail, except the compressor. Did you put PAG 150 oil in the compressor yet? The other part that fails sometimes is the original POA valve. If you still have the original POA valve, it is important to NOT introduce oil when re-charging. In other words, do not buy freon that has oil added to it. I have completely restored the A/C in my 72 and it blows ICE cold air. Any other questions, feel free to PM me.

04-08-2008, 01:13 AM	#4
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: What do you replace mostly when fixing A/C [QUOTE= I haven't vacumed it like it should, QUOTE] That is your problem. Pulling vacuum not only removes all of the moisture, and it lets you know if there are any leaks. If your new dryer is exposed to atmosphere for very long it will also be contaminated with moisture. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/ Last edited by john; 04-08-2008 at 01:16 AM.

04-08-2008, 11:51 PM	#5
Luis_gz06 Senior Member Join Date: Feb 2006 Location: Las Vegas Posts: 1,378	Re: What do you replace mostly when fixing A/C Thanks everyone! I am using r134 refrigererant. Compressor is new, fan works in all 3 speeds, and its a 70 truck. __________________ 1972 Chevrolet Blazer 4x4 (Almost done stay tuned) 1970 Chevrolet Pickup Longhorn CST/20 (SOLD)

04-09-2008, 01:14 AM	#6
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,996	Re: What do you replace mostly when fixing A/C Too bad you are not in So Calif...I'd have you cruise over and take a look at it. I have all the tools to do A/C now.

04-09-2008, 02:21 AM	#7
69heavychevy Registered User Join Date: Jan 2007 Location: Garland,TX Posts: 431	Re: What do you replace mostly when fixing A/C yea be sure to vacumm, if not you can kiss your new compressor good bye in a few months. dont forget the condensor, very important component and often overlooked. dont know if this older trucks had evaporators but thats also something too look at if equipped with. good luck! Last edited by 69heavychevy; 04-09-2008 at 02:31 AM.



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