Great tool and video! I’ve recently got to know these compressors due to issues with my AC on an Audi S3. 1. Mine had a groaning noise coming through into the interior, still cold and no noise in the engine bay. - evacuated and recharged.. resolved! 2. A few months later (on a stinking hot day) the aluminium safety hub sheered off. Don’t know why. - I bought a 2nd hand denso compressor cheap and used it’s sheer hub. Actually changed it in situ by putting a socket on the central nut, and rotating the remains of the aluminium off. Didn’t need to discharge/recharge or remove the compressor. It was fiddly but doable. The garage wanted $1800 (new compressor etc) I did this fix for $100, knowing that it might well have to have the full fix anyway. 6 months later it is still running perfectly. My question is, if the compressor hasn’t seized, why would the aluminium sheer hub give way? (It is a powerful car ~200kw).
Hey Peter, it's not uncommon for the aluminum breakaway hubs to just fail after a while, they are very fragile. I've seen a few that are still running but have cracks in the thinnest part of the hub, i.e. they were going to fail in a few weeks or months.
Doesn't sound right for a bearing, knocking should be there whenever the engine is running. It might be the torque limiter hub is mostly broken, but more likely internal problems with the compressor. Does it still cool the air?
Thanks for the video. I have a question for you though. Do you know what the symptoms are when this bearing starts to go? My AC is still blasting pretty cold but I stopped using it since it seems to cause a kind of uneven idle when stopped at a light and the A/C is on. Also when I cold start the car I get a kind of short clacking noise not long after starting, this is on an 07 Benz ML350... I'm guessing whatever computer controls this just tries the compressor regardless of saying to leave it off on the climate control. When I recently replaced the serpentine belt I rotated the compressor by hand and it seemed to move okay but it was kind of sticky... or felt like it was hanging up the first couple rotations... almost like there was dirt in the back of the pully. I am just trying to determine if I can get away with replacing this pulley and bearing, or if I need to bite the bullet and get a whole new compressor. Thanks for your help if you have any ideas.
With the belt off your compressor pulley should rotate with a little bit of resistance, but it should be a smooth, even resistance. If it feels like crunchy or stiff, or you can hear any noises it will most likely be a bad pulley bearing, bad bearings inside the compressor are also possible but they are clean and PAG oil lubricated and much less likely to fail than the pulley. A clacking noise after startup could be anything, or do you for some reason think it also comes from the compressor? I would disconnect the compressor control valve (back of the compressor body and see if that startup noise goes away. I think your ML might set a fault code if you disconnect the control valve, might need to clear it after plugging the valve back in. With the control valve disconnected the compressor swashplate will stay at it's minimum angle ( the same as A/C off ). In this way I think you could determine if the noise has to do with the compressor or something else. Don't get a new compressor if your current is performing well. If the compressor fails at all internally the performance will degrade quickly and it will get noisy all the time, you would hear it at idle. Replacing the pulley is cheap.
@@Detroitthermo Thank you so much for the reply Erik. The only reason I thought it was related to the compressor was because of the way the pulley felt when I replaced the belt. Funny thing is with the old belt it was missing one of the outer most ribs. That could have also been damaged before I had replaced an idler pulley that went bad about a year ago. I also first replaced the belt with a Continental belt that started squealing like a witch not long after installing in at higher rpm's. I then put a Benz belt on and that stopped. Anyway, when I was rotating the compressor pully it wasn't the smooth but with some resistance feeling that I'm guessing is similar to the way both the alternator and power steering pump feel when you have the belt removed. I've not tried disconnecting as you describe yet. When I run the A/C it doesn't make any clacking/crunch noise... only notice that idle is not smooth at stop lights since something is causing a more strain than normal when the compressor is engaged, or the swage plate as you described is more fully pushing to do it's thing. When I do that first cold start in the mornings and I hear the clack noise the idle drops then surges just after this strain is removed. Makes me wonder if it is the bearing then the pulley is wobbling more when it's cold and some strain is placed on it. I'd love if this issue is just the pulley and I don't have to put a new compressor on it. Anyway, I'm working from home today so when I can sneak out to the garage or finish for the day in a few hours I'll take the tension off the belt, and see what it feels like now when I rotate it. I'll also try wiggling it from side to side to see if there's any play that might also point to the bearing. The car does have 156K miles on the clock so I know a compressor is not out of the question but it's so odd how it only makes the clack/grind noise for less than a second on cold starts. Thanks again.
@@Detroitthermo Well I just checked it..... it didn't feel like it was sticking/hanging when I was rotating it this time, however, I did twist, or push on it on the front from side to side.. and push/pulled on it a bit and it felt like there was play in it. I think I'll go ahead and order the part, and your tool tonight. I priced the pulley at the dealership and holy cow, they started out at $350 and tried to get me to buy at $303 with a discount..LOL... think I'm going to try eBay for $40 first along with your tool...... If you have any additional thoughts please let me know and thank you again for your time Erik.
@@ZaphodsPlanet That's what I would do too, cheapish pulley and change it yourself. $40 is really cheap though, hope it is OK. For $350 you could buy an OEM Denso compressor and use only the pulley!
Yeah, I just re-read what you've said, and I'll change my advice. It does sound like your pulley bearing isn't perfect anymore and could use replacing, but if you can't feel something serious, it can't be causing your engine to bog down at idle with A/C on. I guess I would probably change the pulley because it's easy, but I think your problem is somewhere else.
Great tool and video!
I’ve recently got to know these compressors due to issues with my AC on an Audi S3.
1. Mine had a groaning noise coming through into the interior, still cold and no noise in the engine bay.
- evacuated and recharged.. resolved!
2. A few months later (on a stinking hot day) the aluminium safety hub sheered off. Don’t know why.
- I bought a 2nd hand denso compressor cheap and used it’s sheer hub. Actually changed it in situ by putting a socket on the central nut, and rotating the remains of the aluminium off. Didn’t need to discharge/recharge or remove the compressor. It was fiddly but doable.
The garage wanted $1800 (new compressor etc) I did this fix for $100, knowing that it might well have to have the full fix anyway.
6 months later it is still running perfectly.
My question is, if the compressor hasn’t seized, why would the aluminium sheer hub give way?
(It is a powerful car ~200kw).
Hey Peter, it's not uncommon for the aluminum breakaway hubs to just fail after a while, they are very fragile. I've seen a few that are still running but have cracks in the thinnest part of the hub, i.e. they were going to fail in a few weeks or months.
Hey thanks for the video! I'm curious if a bad bearing could cause heavy knocking from the compressor when the ac button is engaged?
Doesn't sound right for a bearing, knocking should be there whenever the engine is running. It might be the torque limiter hub is mostly broken, but more likely internal problems with the compressor. Does it still cool the air?
Thanks for the video. I have a question for you though. Do you know what the symptoms are when this bearing starts to go? My AC is still blasting pretty cold but I stopped using it since it seems to cause a kind of uneven idle when stopped at a light and the A/C is on. Also when I cold start the car I get a kind of short clacking noise not long after starting, this is on an 07 Benz ML350... I'm guessing whatever computer controls this just tries the compressor regardless of saying to leave it off on the climate control. When I recently replaced the serpentine belt I rotated the compressor by hand and it seemed to move okay but it was kind of sticky... or felt like it was hanging up the first couple rotations... almost like there was dirt in the back of the pully. I am just trying to determine if I can get away with replacing this pulley and bearing, or if I need to bite the bullet and get a whole new compressor. Thanks for your help if you have any ideas.
With the belt off your compressor pulley should rotate with a little bit of resistance, but it should be a smooth, even resistance. If it feels like crunchy or stiff, or you can hear any noises it will most likely be a bad pulley bearing, bad bearings inside the compressor are also possible but they are clean and PAG oil lubricated and much less likely to fail than the pulley. A clacking noise after startup could be anything, or do you for some reason think it also comes from the compressor? I would disconnect the compressor control valve (back of the compressor body and see if that startup noise goes away. I think your ML might set a fault code if you disconnect the control valve, might need to clear it after plugging the valve back in. With the control valve disconnected the compressor swashplate will stay at it's minimum angle ( the same as A/C off ). In this way I think you could determine if the noise has to do with the compressor or something else. Don't get a new compressor if your current is performing well. If the compressor fails at all internally the performance will degrade quickly and it will get noisy all the time, you would hear it at idle. Replacing the pulley is cheap.
@@Detroitthermo Thank you so much for the reply Erik. The only reason I thought it was related to the compressor was because of the way the pulley felt when I replaced the belt. Funny thing is with the old belt it was missing one of the outer most ribs. That could have also been damaged before I had replaced an idler pulley that went bad about a year ago. I also first replaced the belt with a Continental belt that started squealing like a witch not long after installing in at higher rpm's. I then put a Benz belt on and that stopped. Anyway, when I was rotating the compressor pully it wasn't the smooth but with some resistance feeling that I'm guessing is similar to the way both the alternator and power steering pump feel when you have the belt removed. I've not tried disconnecting as you describe yet. When I run the A/C it doesn't make any clacking/crunch noise... only notice that idle is not smooth at stop lights since something is causing a more strain than normal when the compressor is engaged, or the swage plate as you described is more fully pushing to do it's thing. When I do that first cold start in the mornings and I hear the clack noise the idle drops then surges just after this strain is removed. Makes me wonder if it is the bearing then the pulley is wobbling more when it's cold and some strain is placed on it. I'd love if this issue is just the pulley and I don't have to put a new compressor on it. Anyway, I'm working from home today so when I can sneak out to the garage or finish for the day in a few hours I'll take the tension off the belt, and see what it feels like now when I rotate it. I'll also try wiggling it from side to side to see if there's any play that might also point to the bearing. The car does have 156K miles on the clock so I know a compressor is not out of the question but it's so odd how it only makes the clack/grind noise for less than a second on cold starts. Thanks again.
@@Detroitthermo Well I just checked it..... it didn't feel like it was sticking/hanging when I was rotating it this time, however, I did twist, or push on it on the front from side to side.. and push/pulled on it a bit and it felt like there was play in it. I think I'll go ahead and order the part, and your tool tonight. I priced the pulley at the dealership and holy cow, they started out at $350 and tried to get me to buy at $303 with a discount..LOL... think I'm going to try eBay for $40 first along with your tool...... If you have any additional thoughts please let me know and thank you again for your time Erik.
@@ZaphodsPlanet That's what I would do too, cheapish pulley and change it yourself. $40 is really cheap though, hope it is OK. For $350 you could buy an OEM Denso compressor and use only the pulley!
Yeah, I just re-read what you've said, and I'll change my advice. It does sound like your pulley bearing isn't perfect anymore and could use replacing, but if you can't feel something serious, it can't be causing your engine to bog down at idle with A/C on. I guess I would probably change the pulley because it's easy, but I think your problem is somewhere else.
hello sir could you give me the reference of the tool to unscrew the air conditioning pulley thank you sir
Hello Felix Albano, I added a link for my tool and a description of where to find the puller