On Thanksgiving, I started hearing an intermittent scraping sound, but it was kinda hard to track down since every time I looked under the hood it had gone away.

Yesterday, I took a short drive and noticed that the sound went away when I turned down the temp on the climate control enough that the AC would turn on. So, I stopped off at a friend's place and looked under the hood. Sure enough, the AC pump was having problems. The first thing I noticed was the smell (burnt brake type of smell with a bit of burnt rubber) and that there was a crusty layer of what appeared to be clutch material coming out of the clutch. You can see it in this pic between the belt and the body of the pump:
http://www.geocities.com/mike_lackey/Vette_AC.html

The AC Pump was also extremely hot. While we were looking at the car, the accessory belt snapped... probably because of the heat. I got a replacement belt, waited for it to cool off, and then headed home. I wanted to try to save the new belt I just put on, so when I got home, I poured some water on it to cool it off. The water just instantly turned to steam until I'd poured almost a liter bottle onto it.

Now for the questions. Is the problem the clutch or the pump itself? Even if it's just the clutch, will that much heat have destroyed the pump? It was still working well even on Friday when the clutch was destroying itself. I'm rather tight on cash since I just purchased the car, so where's the cheapest place to buy a replacement pump? Or, is there any easy (and cheap) way to bypass or remove the pump. Looking at the other pulleys, I don't see how to route a belt in there without it, but I thought AC was an option, so there must be Vettes without it.


[Modified by Darcane, 5:32 PM 11/29/2003]

 

Any obvious leaks such as compressor oil on the underside of the hood (compressor shaft seal leak) or ice on the windshield (evaporator leak)? Try to turn the outer hub by hand. Should turn freely with minimal resistance. If not, compressor has seized. If it turns ok and there's no indication that the oil leaked out, should only be the clutch assembly.

 

The A/C compressor is most likely seized.

The burning is the belt slipping on the non moving pulley when the clutch is engaged. That's why it burned off.

The cheapest thing is to unplug connector on the A/C comp.

Then, take it to a shop to get it fixed. :thumbs:

 

Actually, you've got it pretty much backwards. It was only making noise when the clutch was disengaged and the pump was not being used. It went away when the AC was turned on. I confirmed that this was the case by pulling the electrical connection off and running the car.

I played around with it some more today. I removed the belt and turned the inner hub (not the pulley itself) and it turned without any trouble. There was resistance to turning, but not much and I could turn it by hand easily. The pulley turns also, but it wobbles badly and feels quite loose. So, I'm quite certain it's just the AC clutch unless the extreme heat destroyed the pump too.

So far, the cheapest I've found for a pump is about $400, and that doesn't include installation. :(

 

Well then you are in luck.....

If it's just the clutch, and the A/C works fine, I would just replace the clutch!

Simple as that! :thumbs:

 

Hmm. Got any tips on how to pull the clutch off?

I don't have a set of manuals (yet... should be here in a week or so). I removed the bolt that goes through the pulley, and removed the front piece. The pulley itself fits quite loosely, but won't slide or pry off. What keeps this on? I'm not seeing any bolts or anything, but there is clutch dust packed in everywhere!

 

I watched the shop put my A/C clutch back together. Didn't see them break it down. It just bearly fits under the metal A/C lines (another millimeter and it wouldn't have fit.).

The mechanic said it took about 30 minutes to get it off, no special tools.

After I saw the pieces of the old clutch, I was surprised that it didn't just fall off!

 

GM recommends the a/c be discharged and the main hose removed, but you might try to get it off with the hoses attached. Sometimes there's enough play in the hoses so that the compressor can be removed and stood on it's backside which may make it easier - just don't bend any hard metal lines as that will create a restriction. Face plate is held on with a 10mm bolt and you need to hold it with a strap wrench or some oil filter pliers while you remove it. The plate should then slide off but keep an eye out for any shims (1/4 in. washers) that are on the end of the shaft. Pulley is then held on with a snap ring as is the coil underneath it and it will definitely help if the compressor is standing up. Install in reverse order making sure the snap rings are fully seated. Shim the face plate until there is a clearance of .020 between it and the pulley (if you're buying the ac delco clutch, you will have to order the shim kit separately). Torque the bolt to 10ft/lbs.

 

Hmm. Got any tips on how to pull the clutch off?

I don't have a set of manuals (yet... should be here in a week or so). I removed the bolt that goes through the pulley, and removed the front piece. The pulley itself fits quite loosely, but won't slide or pry off. What keeps this on? I'm not seeing any bolts or anything, but there is clutch dust packed in everywhere!

 

Should be held on by a snap ring which fits into a groove cut into the compressor snout. Use snap ring pliers to remove the ring and the pulley should slide right off. Here's a picture (I hope) of the snout. Second groove at the base is for the snap ring that holds on the coil. Remove it after the pulley is off.




[Modified by SunCr, 6:53 PM 12/3/2003]

 

SunCr, thanks for the help. I found the snap ring and should be able to get it disassembled.

I'm not sure how I sent that duplicate post up there...