A/C issues
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Joined: Aug 2010
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From: Brunswick GA
A/C issues
Today I took the 81 out for a drive to the lake and about 30 min into the trip I began to notice a strange smell coming from the engine bay, a bit like burning rubber. I pulled over and noticed the a/c compressor would lock up, causing the belt and pulley to slip. This ONLY happened when the a/c was turned OFF. However, the compressor seemed to run normally while the a/c was turned on and blew out cold air like normal. Also, it might be important to add that I just recently added a new compressor belt and recharged the compressor about two weeks ago with r134 (I had removed the a/c belt about 6 months earlier and didn't replace it until recently because I had no need for it during the colder winter months). Running the car with the a/c ALWAYS on seems to put a lot of strain on these old cars, causing it to get very hot and nearly overheat.
What is the cause of this and how do I go about fixing it?
Thanks in advance for the help
What is the cause of this and how do I go about fixing it?
Thanks in advance for the help
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Joined: Aug 2010
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From: Brunswick GA
Usually a compressor will only lock up if the a/c is turned ON, meaning that it is low on freon, however mine only locks up with the a/c turned off. I drive my vette almost daily and I didnt have this problem until today
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From: Brunswick GA
UPDATE: Just removed the belt and took a look at the pulley, it spins freely with no resistance at all, however, I can hear some sort of metal rolling around inside the pulley. Is this normal? Im starting to believe that it may be the bearing but any advice is appreciated
Melting Slicks
Joined: Mar 2009
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With A/C off does the center of the clutch try to rotate? When it is off only the outer pulley should turn. With belt off there should not be any noise just smooth rotation when turned. Really unsual for the belt to slip with the A/C off. Pic. of mine.
Upper right is center of clutch. Two bottom pieces are the pulley with bearing in lower left piece. mike...
Upper right is center of clutch. Two bottom pieces are the pulley with bearing in lower left piece. mike...
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Joined: Aug 2010
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From: Brunswick GA
The clutch does attempt to rotate while the a/c is off but it is very slow. Also, the burning smell returns inside the cabin within a few seconds of turning the car on when the a/c is off, however it doesnt seem to be the belt causing this smell (the smell isnt as strong when standing near the compressor but is very faint). The clutch rotates normally while the a/c is on
Melting Slicks
Joined: Mar 2009
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OK. Ck. the clearance between the back of clutch face, upper right in pic. and the front of the pulley hub, lower left in pic.. The bare metal surface on the hub is where the clutch friction surfaces lock together when the A/C is turned on. It should be about .010-.015 in.. Mine is a tight .012 in.. If the face of the pulley hub or the backside of the clutch center that pulls in when the A/C is turned on, are too close that will cause the symptom, noise and smell. The two metal plates may be slightly rubbing together? That is causing the center of the clutch to rotate slightly when the A/C is off. I hope that makes sense. What I can suggest. mike...
Last edited by mds3013; Jun 16, 2012 at 09:31 PM.
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Melting Slicks
Joined: Mar 2009
Posts: 3,126
Likes: 15
The front center clutch piece can be pulled off with a puller after removing a 9/16 in. nut. Then you can inspect the two surfaces. They should be flat and smooth. When the center is pressed back on then you can set the gap. I was instructed to set this gap at .010 in.. Good luck with it. mike...
The nut on the compressor shaft is upside down in my pic..
The nut on the compressor shaft is upside down in my pic..
Last edited by mds3013; Jun 16, 2012 at 09:37 PM.
Thread Starter
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Joined: Aug 2010
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From: Brunswick GA
OK. Ck. the clearance between the back of clutch face, upper right in pic. and the front of the pulley hub, lower left in pic.. The bare metal surface on the hub is where the clutch friction surfaces lock together when the A/C is turned on. It should be about .010-.015 in.. Mine is a tight .012 in.. If the face of the pulley hub or the backside of the clutch center that pulls in when the A/C is turned on, are too close that will cause the symptom, noise and smell. The two metal plates may be slightly rubbing together? That is causing the center of the clutch to rotate slightly when the A/C is off. I hope that makes sense. What I can suggest. mike...
Melting Slicks
Joined: Mar 2009
Posts: 3,126
Likes: 15
I rented mine from Auto Zone on their lease program. Pay a deposit, return when finished and they refund the deposit. The pullers and installers be listed in the A/C tools of course. Holding the clutch center is the biggest problem. Their tool does not fit my '77. I used an old air pump belt squeezed around the outer edge of the clutch center and was able to remove/tighten the nut and remove/press the center back on. Kinda like a strap wrench. mike...
This is their power steering pulley remover/installer. The A/C clutch tools look very similar. I can't believe I did not take a pic..
This is their power steering pulley remover/installer. The A/C clutch tools look very similar. I can't believe I did not take a pic..
Last edited by mds3013; Jun 16, 2012 at 10:18 PM.