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Compressor noise


epricedright

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My compressor makes a screaming noise (bearing?) when it is disengaged. It does this once it has warmed up. It will go away when the compressor engages. I stated earlier in another post that it screamed while engaged...I had that backwards due to I had forgotten since I've hardly driven her lately. Is this the clutch bearing going out or am I gonna need to replace the compressor? I haven't driven her fearing the compressor might go out completely reulting in "black death".

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So what's involved in replacing the clutch bearing? Never done it before. Is the clutch bearing the pulley on the outside furthest away from the compressor? Will a 3 jaw pulley remover take it off ok? I've read some post referring to hub bearing and compressor bearing. What's the diff? I imagine the compressor bearing is in the compressor itself...correct? But hub bearing?

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You will need a puller/installer specifically for removing the hub, see this tool

http://www.etoolcart.com/index.asp?PageAct...ROD&ProdID=1277

The AC hub bearing and AC pulley bearing are the same. Using that tool you pull the clutch plate and the pulley with bearing should come off relatively easy, although a puller may be required. I purchased the pulley at NAPA for my 91 for about $90 if I recall. You may be able to just buy a new bearing and press it in

post-3-1130156288_thumb.jpg

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You can replace just the bearing - a bearing supply house will have the bearing for less than $10. You will need to grind off the stakes and re-stake the new bearing in place though.

Some auto parts stores rent the puller tools. Be sure the thread matches your specific compressor and you will also need to set the clutch air gap distance upon reassembly.

The R&R of the clutch bearing will not disturb the refrigerant charge either.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Thank you Larry, Mike and Kevin!

I'm still a little confused. Is the clutch bearing the same as the hub bearing and pulley bearing...all the same bearing, just different names?

So in order to do this job, are these the steps involved:

1. Remove the clutch plate w/ the special clutch plate removal tool.

2. Remove the pulley bearing...should pull right off w/ no puller if lucky.

If not, can I use a standard gear puller? The bearings that are bad are in

this pulley.

3. I will then be able to see and inspect the clutch coil. In order to remove

the clutch coil if necessary...will I need that special clutch removal tool?

4. Replace pulley w/ new pulley that have the bearings inside, or have the

new bearings pressed into the old pulley. I'm not sure of a place to go to

have the bearings pressed into the pulley, any ideas?

5. Replace clutch plate.

At what step do I measure the clutch air gap distance and where is this clutch plate? Is there a snap ring somewhere I need to remove? How can I find out what size threads are on my compressor so I know which clutch plate tool to rent or buy? Sorry for all the questions.

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There is only one bearing, its part of the pulley/hub, its what the serp belt rides on. You may be able to buy just a bearing or you can buy the entire pulley with the bearing attached. If I recall, I sent a new AC pulley to adallak that I never used for my 91 4.9, maybe he could take a photo of it for you to show you what it looks like.

I can lend you my removal/installation tool if you like, I bought them for my 91, 4.9

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OK, thanks for clarifying that! I was wondering what the heck, where are all these bearings? blink.gif

Thanks for the offer Mike! That would be really nice if you wouldn't mind.

Am I anywhere close to the procedures involved?

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I am going to leave the steps to Kevin. It looks like you have it correct. However, step 2, Remove the pulley bearing...should pull right off w/ no puller if lucky. If not, can I use a standard gear puller? The bearings that are bad are in

this pulley.

MORE CORRECTLY, You will be removing the pulley, the bearing is pressed into the pulley

If your compressor is NOT blowing fuses yet, you can be reasonably sure that your coil is not shorted out from heat yet. Don't let it go too long otherwise it will look like this after it overheats, I was blowing fuses, the blown fuse takes out the AC clutch coil, the cooling fans and the horn (if I recall).

post-3-1130194308_thumb.jpg

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That's what I meant (pulley)....thanks! Yea, I hope you're right as my AC works fine, just noisy.

I read your post and saw what you went through w/ the black death(WOW!) ohmy.gif ...haven't driven her lately fearing that might happen to me as well.

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Everyone is giving great advice.

The only thing I wanted to add is when you're putting it back together, do no hammer/tap the clutch back onto the shaft.

You need to use the tool to press it back on.

If tapped back on, it will almost always screw up the compressor.

In pressing the clutch plate back on, this is when/where you set the gap.

Do not press the clutch plate on until it contacts the clutch. This will cause the compressor to run all the time.

The theory is to leave a gap and when the clutch coil is energized, this will magnetically draw the clutch plate in contact with the clutch and start the compressor.

Hope this makes some sense.

Barry

2008 STS V8
2016 Colorado Z71
1970 Corvette LT-1 Coupe

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Thanks Barry! Yep that makes perfect sense. The mud is becoming more clear now! smile.gif

So I take it I need to measure the distance between the clutch plate and clutch before removing the clutch plate and try to get it back to that same gap when replacing the clutch plate.

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Should the new pulley just slide right onto the shaft?  If not, do I need a pulley installer or can I tap it on?

I think that my installer should pull the clutch plate back into position, is that right Barry? I am going to lend epriced my removal/installer tool....

I have this tool:

http://www.etoolcart.com/index.asp?PageAct...ROD&ProdID=1277

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That's what I meant (pulley)....thanks! Yea, I hope you're right as my AC works fine, just noisy.

I read your post and saw what you went through w/ the black death(WOW!) ohmy.gif ...haven't driven her lately fearing that might happen to me as well.

If you have doubts, you can take your serp belt off and feel the pulley for looseness, wobble, roughness, etc..

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If your compressor is NOT blowing fuses yet, you can be reasonably sure that your coil is not shorted out from heat yet.  Don't let it go too long otherwise it will look like this after it overheats, I was blowing fuses, the blown fuse takes out the AC clutch coil, the cooling fans and the horn (if I recall).

I was hoping you were right about my coil being ok.

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As Emeril would say, Oh Yea Babe.....   How is this for a nice illustration!

BAM! That's the ticket! That clarifies the whole picture. Where did you find that? That's not in the FSM is it?

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If your compressor is NOT blowing fuses yet, you can be reasonably sure that your coil is not shorted out from heat yet.  Don't let it go too long otherwise it will look like this after it overheats, I was blowing fuses, the blown fuse takes out the AC clutch coil, the cooling fans and the horn (if I recall).

I was hoping you were right about my coil being ok.

Someone else recently went through this procedure, we will need to search, they replaced the pulley/bearing and reassembled it..... after it was reassembled they discovered that the coil was shorted and it was blowing the 5 amp fuse (or 10 amp I forget).

Here it is YEAH! , see this GREAT thread (nice photos by MAC), MAC had to replace his clutch coil also (darn my memory is good):

http://caddyinfo.ipbhost.com/index.php?sho...&hl=clutch+coil

There should be a way to measure the resistance of the coil to ensure its OK, what do you think about that theory?

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If your compressor is NOT blowing fuses yet, you can be reasonably sure that your coil is not shorted out from heat yet.  Don't let it go too long otherwise it will look like this after it overheats, I was blowing fuses, the blown fuse takes out the AC clutch coil, the cooling fans and the horn (if I recall).

I was hoping you were right about my coil being ok.

Someone else recently went through this procedure, we will need to search, they replaced the pulley/bearing and reassembled it..... after it was reassembled they discovered that the coil was shorted and it was blowing the 5 amp fuse (or 10 amp I forget).

Here it is YEAH! , see this GREAT thread (nice photos by MAC), MAC had to replace his clutch coil also (darn my memory is good):

http://caddyinfo.ipbhost.com/index.php?sho...&hl=clutch+coil

There should be a way to measure the resistance of the coil to ensure its OK, what do you think about that theory?

Yeah, that makes a lot of sense. Too bad Mac didn't get to test his first. sad.gif Lots of work to have to do twice. Any electrical gurus know how to test the coil?

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....

There should be a way to measure the resistance of the coil to ensure its OK, what do you think about that theory?

Theory is OK. But with modern A/C clutch coils, there is a potential problem for DIY'ers reading the DC resistance of the coil with an Ohmeter. A clutch coil that is not faulty, and is operating as designed, will display a very low DC resistance (as in 1 Ohm or less). Resistance of 1 Ohm or less can be mistakenly diagnosed as a "shorted" or faulty coil winding.

Most modern GM A/C clutch coils will measure ~~ 1 Ohm resistance. But that is only the DC resistance of the "pull-in" coil winding. After the clutch is engaged, the coil circuit resistance is increased (via smoke and mirrors) such that the "hold-in" coil resistance is much higher.

The "hold-in" coil resistance can be calculated. But but not easily measured with an Ohmeter.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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