A/C Compressor issue

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Feb 2, 2015 | 05:00 AM

Brian Felts

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A/C Compressor issue

Guys as I am getting to know my 1988 Vette I noticed the A/C compressor clutch will not kick off. I unplugged the electrical connector and it still stays engaged with the system off on the dash it still stays on. There is gas in the system, the pipes get frost on them under the hood.

Am I going to need a new comp? or is there something to unlock the clutch?

Thanks
Brian Felts

Feb 2, 2015 | 06:50 AM

Red86Z51

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Brian, since you've eliminated the electrical aspect of clutch engagement by removing the connector (and the compressor still remains engaged), you've narrowed it down to the only other possibility--a mechanical failure of the clutch. You will need to remove the clutch to repair the failure, or replace the compressor. The frosted lines would be expected since the clutch never disengages. Fix the clutch, the frost goes away.

Dave

Feb 2, 2015 | 07:05 AM

Brian Felts

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In all of my years working on cars I have never messed with a A/C Clutch. Do I need a special tool? Any tips on how to do this, I think I still have the R12 system (Nothing looks touched from factory) I hate to bust the system open.

Thanks!!!
Brian

Feb 2, 2015 | 01:55 PM

Hot Rod Roy

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Replacing the a/c clutch does NOT require the removal of the compressor. Don't touch the refrigerant fittings. If you get frost on the lines, your compressor is working fine!

Feb 2, 2015 | 03:10 PM

desertmike1

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I believe your compressor is an Harrison R4, and the Clutch drive plate (center plate) requires a special "Install/removal" tool.

Check your air gap between the compressor pulley, and the Driven plate.. it should be about the thickness of a business card, if it is too tight this could cause the compressor to run full time.

Feb 2, 2015 | 03:36 PM

pcolt94

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with all the info above. If the bearing is not making noise, heated up and seized on the shaft, it will probably come off. I have some experience with clutches but definitely not an expert on them.

You may or may not have all the tools to do the job. In one case I did not have a really long pair of E clip spreader or compressor. The clutch clearance required to be set needs to be done properly and shims are used to do this.

Its not a high tech job but it's the little things you need to know to get it done properly. Make sure you don't damage the front seal if it is not going to be replaced.

Feb 2, 2015 | 08:00 PM

Red86Z51

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Quote:

Originally Posted by desertmike1

I believe your compressor is an Harrison R4, and the Clutch drive plate (center plate) requires a special "Install/removal" tool.

No, 1987 was the last year for the R4. In 1988 GM started installing Nippondenso 10PA20C Compressors.

As Hot Rod Roy said, you can remove the clutch on the car without opening up the system and losing your refrigerant. If you don't have a factory service manual, do a search here on the forum for info on removing the clutch, there have been many discussions on that topic.

Feb 2, 2015 | 09:00 PM

Brian Felts

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Thanks guys, I will have a look at it tomorrow and let you know what I find. The car is in perfect shape but I do have some gremlins from where it sat for a long time.

Brian