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Discussion Starter #1
Hi all, my car has been making a sort of grumbling noise when idling after a cold start. The noise goes away once warm but it's pretty noticable when cold; I think I've pin-pointed the aircon compressor as the culprit.

Has anyone on here ever replaced the bearing in this clutch? I've seen a few american bmw sites where people have done this but I wonder if anyone here has? or indeed if the UK systems may be different. As far as I understand you undo a 10mm bolt and then remove a circlip to get the clutch and bearing off, then press a new one in.

Thanks :thumbsup
 

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They are a fookin pig as the bearing is pressed in which itself is not a problem but then they peen over the edge so you cannot get the bearing out without damaging the pulley...:mad
Plus the bearing is a special size which ONLY fits air-con compressors and is not availiable as a standard bearing. The cheapest I found a bearing was £70, so I got a second hand warrantied compressor. Plus when you take the pulley off the magnetic clutched is shimmed to a certain spec and I have yet to find out the correct procedure for shiimming them. Too tight and the clutch will drag, too loose and the magnetic clutch will not engage properly...:thumbsup
 

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Discussion Starter #3
So doable then :hihi

From the pictures I saw on an american site, it made it looks easy!
To be honest, the noise is soo annoying that it's worth a punt, maybe even just get access to the bearing and spray some grease in it as it's probably all washed out. I've got an SKF catalogue here too which I used at uni and I can't believe they won't have a bearing of the same dimensions :confused What about putting another clutch from a good compressor on?
When you say it needs shimming, I've got a stack of very fine shims from the wiper mechanism of an e34 which I think could be the right diameter, could it be a case of trial and error or are they really that hard to get right?

Not trying to disagree with your experience, I'm just tight is all :)
 

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So doable then :hihi

From the pictures I saw on an american site, it made it looks easy!
To be honest, the noise is soo annoying that it's worth a punt, maybe even just get access to the bearing and spray some grease in it as it's probably all washed out. I've got an SKF catalogue here too which I used at uni and I can't believe they won't have a bearing of the same dimensions :confused What about putting another clutch from a good compressor on?
When you say it needs shimming, I've got a stack of very fine shims from the wiper mechanism of an e34 which I think could be the right diameter, could it be a case of trial and error or are they really that hard to get right?

Not trying to disagree with your experience, I'm just tight is all :)
Been thorough the bearing catalogues and even a massive supplier near me says for that compressor its a 'special' air con bearing. Check your type of compressor as they use about 4 different types on E36's. I couldnt be bothered to piss around for the price of a good compressor as everytime I fixed one thing on mine, something else siezed.
I have the data for shimming them somewhere, but the shims are tiny as they sit behind the pully where the 5mm allen screws goes thorough.
Possible to fit another clutch, thats what I did, it lasted 2 weeks before it siezed again. I still have 2 sat here in my toolbox...:hihi
 

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Discussion Starter #5
Damn you Steve, you've turned my nice positive mood on this matter into a bad one lol

I'll still try and fix it for free first, if it all goes wrong then I'll get another compressor. Bit annoying but I can't bear this grumbling noise anymore.
 
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Ill try and find the bearing number later, you can see it when you remove the pulley. You will need a puller to get the pulley off the compressor as they are not that strong and break if you lever them. :thumbsup
Its not a difficult job, just a fookin pain when you cant get the parts or info...:frown
 

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Discussion Starter #7
Looks like I'll be putting this job off for a little while then.
I'll get the belt off and see how it feels when I spin it, I'll also spray some oil around to see if that helps for now.

What are your thoughts on second hand compressors? My friend has one removed from a 328i but it's been sat in his shed for a few months now and I'm worried that dust and crap may have got in (but that's a risk with any second hand unit surely?) is there a way to clean them before fitting?
 

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Looks like I'll be putting this job off for a little while then.
I'll get the belt off and see how it feels when I spin it, I'll also spray some oil around to see if that helps for now.

What are your thoughts on second hand compressors? My friend has one removed from a 328i but it's been sat in his shed for a few months now and I'm worried that dust and crap may have got in (but that's a risk with any second hand unit surely?) is there a way to clean them before fitting?
They are touch and go, it all depends on how often they have been used. If its not been used in years its fooked. I got one from quarry motors because it came with a 3 month warranty. I wouldnt have bothered if they didnt have one in stock....:thumbsup
 

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Discussion Starter #9
That's what I thought. It was used right up until we took the engine out and the aircon system seemed to be in full working order. Are there traps or filters in aircon systems to collect and rubbish that might get in? I wouldn't want to put something in that might knacker something down the line.

I just took the belt off and started the car and the noise wasn't there so that's confirmed it's the compressor. I couldn't replicate the noise when spinning it by hand though, it must be to do with the force the belt puts on it.
 

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That's what I thought. It was used right up until we took the engine out and the aircon system seemed to be in full working order. Are there traps or filters in aircon systems to collect and rubbish that might get in? I wouldn't want to put something in that might knacker something down the line.

I just took the belt off and started the car and the noise wasn't there so that's confirmed it's the compressor. I couldn't replicate the noise when spinning it by hand though, it must be to do with the force the belt puts on it.
Nothing should be able to get into the system unless it leaks or has been left open. They should be sealed. The reciever dryer is kind of a filter but only take out any moisture inside...:thumbsup
 

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Discussion Starter #11
So a compressor that's been left open for a few months could be perilous then...
I'd love to know if there was a way to clean them out before fitting just to be safe.
 

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So a compressor that's been left open for a few months could be perilous then...
I'd love to know if there was a way to clean them out before fitting just to be safe.
The only way i can think of is to flush it out with the correct PAG oil. You dont want to be taking the compressor itself apart as it will never seal again and they dont sell internal parts for them...:thumbsup
 

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Discussion Starter #13
No no, I don't want to be taking it apart lol
I'm just weighing up my mates one, it's a known quantity but the fact it's been left un-sealed for a while scares me a bit.
 

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Discussion Starter #14 (Edited)
Well we can scrap all this 'just replace the bearings' talk as I investigated further today and the compressor is making a grumbly noise when the clutch is activated too, so I'd say it's had it.
One by one I will get rid of all the rattles and clonks in this bloody engine bay lol
 
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