Secondary Air Injection Pump
04-03-2010, 06:30 PM
#11
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Nice writeup! Mine seems to have quieted down some since I put it back in, and now I don't hear it run unless I listen for it. So this seems to be a bonafide fix for these things.
Now if you can figure out how to rebuild the suspension compressor, you'll be an allroad hero!
Now if you can figure out how to rebuild the suspension compressor, you'll be an allroad hero!
04-04-2010, 12:49 PM
#12
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Thread Starter
Here are a few pics I took of the process.....the fan motor is the round **** looking thing at the right of the curve in the silver intake pipe.
Another view, straight down. There is a 6mm nut (10mm wrench) down on the right side of the bracket that you have to loosen to get the fan assembly out, and it's almost impossible to touch, let alone get a socket on it or even see it due to all the pipes and pieces in the way. I used a socket on a 3" extension, a universal joint, then another 3" extension, then a 10" extension and ratchet to get it loose!
My car is a 2004, and the impellers were only held on by this nut, no circlip. The fan and motor both were pretty clean inside, no rust. Lots of carbon dust tho, which I thought would mean new brushes, but they were like new, as was the commutator.
You need to straighten these 4 tabs on the end of the motor to get the end plate with the bearing in it out. Once you gently tap these straight, you can lay the motor on its side and tap the end cover off the tabs.
Tap the old bearing out and the new one in, only tap the new bearing on the outside race, if you tap it on the inside race you can ruin it.
Bend the 4 tabs on the sides of the motor out, then you can gently tap out the yellow and black brush assembly - it comes out all in one piece. Then remove the armature and tap out the bearing in the bottom. No point in only replacing the one, even it the other isn't noisey right now.
Here are all the parts ready to go back together, look how clean and unworn the commutator is on the armature - looks almost new. It's probably a good idea to hook it up to a battery and try it before you reinstall it in the car, as hard as it is to get it back out again!
Another view, straight down. There is a 6mm nut (10mm wrench) down on the right side of the bracket that you have to loosen to get the fan assembly out, and it's almost impossible to touch, let alone get a socket on it or even see it due to all the pipes and pieces in the way. I used a socket on a 3" extension, a universal joint, then another 3" extension, then a 10" extension and ratchet to get it loose!
My car is a 2004, and the impellers were only held on by this nut, no circlip. The fan and motor both were pretty clean inside, no rust. Lots of carbon dust tho, which I thought would mean new brushes, but they were like new, as was the commutator.
You need to straighten these 4 tabs on the end of the motor to get the end plate with the bearing in it out. Once you gently tap these straight, you can lay the motor on its side and tap the end cover off the tabs.
Tap the old bearing out and the new one in, only tap the new bearing on the outside race, if you tap it on the inside race you can ruin it.
Bend the 4 tabs on the sides of the motor out, then you can gently tap out the yellow and black brush assembly - it comes out all in one piece. Then remove the armature and tap out the bearing in the bottom. No point in only replacing the one, even it the other isn't noisey right now.
Here are all the parts ready to go back together, look how clean and unworn the commutator is on the armature - looks almost new. It's probably a good idea to hook it up to a battery and try it before you reinstall it in the car, as hard as it is to get it back out again!
04-09-2010, 06:51 AM
#13
AudiWorld Member
Thanks for the great post, Dave.
Mine's been intermittently screaming. You should hear it in an indoor parking garage!
I'll wait till it's a problem. Did this definitely solve the problem for you?
Mine's been intermittently screaming. You should hear it in an indoor parking garage!
I'll wait till it's a problem. Did this definitely solve the problem for you?
04-09-2010, 09:04 AM
#14
AudiWorld Member
Thread Starter
Mine is as quiet as new, so I'm gonna say it was an unqualified success!
In the garage was where my wife said she kept hearing it too, I never heard it till I opened the hood and had her start it up. Now you can't hear it at all, but I assume it's just running quietly, since I did test it before I installed it and it hasn't thrown any codes since!
Really, the only hard part of the job is getting to that nut down on the side of the bracket, once you've done that the rest is very straightforward. Taking the screws out of the coolant reservoir allows you to get a little more room for your hands.
I would recommend using good bearings from a bearing house. It's not that the ones you'd get at Westlake or the Hardware store are substandard, but you need a bearing rated for an electric motor (the RPM determines this) and I again recommend you stay away from Chinese made bearings. if it says China on the box, simply ask for a different brand - this is a common size so they will have them.
When you go to stake the tabs on the top - I used a deep well socket to press the end on tightly till I got the tabs staked over to hold it, otherwise the plate can spring up slightly and it won't be square, which could lead to premature wear or even the noise the other poster experienced.
Look at the commutator carefully, if it looks smooth, don't do anything to it except blow it off with compressed air. If it's badly grooved, you might be able to save it. I chuck it in a drill press and use a smooth file to carefully turn it down, then clean it up with some fine grit paper - don't forget to undercut the mica between segments if you do this, and make sure you blow all of the copper dust out of the nooks and crannies......
For $15 or whatever's worth of bearings and a little time and trouble, it seems worth it to me, compared to the cost of a new one.....
In the garage was where my wife said she kept hearing it too, I never heard it till I opened the hood and had her start it up. Now you can't hear it at all, but I assume it's just running quietly, since I did test it before I installed it and it hasn't thrown any codes since!
Really, the only hard part of the job is getting to that nut down on the side of the bracket, once you've done that the rest is very straightforward. Taking the screws out of the coolant reservoir allows you to get a little more room for your hands.
I would recommend using good bearings from a bearing house. It's not that the ones you'd get at Westlake or the Hardware store are substandard, but you need a bearing rated for an electric motor (the RPM determines this) and I again recommend you stay away from Chinese made bearings. if it says China on the box, simply ask for a different brand - this is a common size so they will have them.
When you go to stake the tabs on the top - I used a deep well socket to press the end on tightly till I got the tabs staked over to hold it, otherwise the plate can spring up slightly and it won't be square, which could lead to premature wear or even the noise the other poster experienced.
Look at the commutator carefully, if it looks smooth, don't do anything to it except blow it off with compressed air. If it's badly grooved, you might be able to save it. I chuck it in a drill press and use a smooth file to carefully turn it down, then clean it up with some fine grit paper - don't forget to undercut the mica between segments if you do this, and make sure you blow all of the copper dust out of the nooks and crannies......
For $15 or whatever's worth of bearings and a little time and trouble, it seems worth it to me, compared to the cost of a new one.....
Last edited by allroaddave; 04-09-2010 at 09:06 AM.
04-09-2010, 07:17 PM
#15
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Dealer thought the same thing here .... but was wrong
I had an identical sound on startup at about 40K miles. Dealer diagnosed as secondary air pump so he installed a new one. Unfortunately the same noise was there afterwards and that was not the fix. Good news was that I got a secondary air pump with installation for free. The odd noise that sounded like a bearing went away about a month later on its own and never came back.
04-10-2010, 07:34 AM
#16
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I think I'm the other poster, and I'm happy to report that after a couple of startups, it's now as quiet as it ever was. I can hear the electric motor running if I open the hood, but all the banshee noises are gone, and from inside the car, it's completely inaudible.
When I did mine, I pulled the coolant reservoir up and out of the way, and the side nut wasn't too bad-it doesn't need to be removed, just loosened enough to slide the bracket up and out. Extensions are your friend. On the other hand, I have a manual, and there might be different breather hoses and such back there based on transmission.
I honed the commutator down a little, but it was really in pretty good shape as it was.
Someone should probably offer rebuild service on these for a reasonable price, given how expensive they are to replace and how easy to fix for a somewhat mechanically-minded person. It'd be a reasonable solution for someone who doesn't want to take it apart themselves.
When I did mine, I pulled the coolant reservoir up and out of the way, and the side nut wasn't too bad-it doesn't need to be removed, just loosened enough to slide the bracket up and out. Extensions are your friend. On the other hand, I have a manual, and there might be different breather hoses and such back there based on transmission.
I honed the commutator down a little, but it was really in pretty good shape as it was.
Someone should probably offer rebuild service on these for a reasonable price, given how expensive they are to replace and how easy to fix for a somewhat mechanically-minded person. It'd be a reasonable solution for someone who doesn't want to take it apart themselves.
04-15-2010, 11:50 AM
#19
AudiWorld Member
Dave, what do you think about this bearing?
I've never used ceramic, but would guess that it would be good for high temp, like on an engine.
http://bearingsdirect.com/store/inde..._detail&p=4212
I've never used ceramic, but would guess that it would be good for high temp, like on an engine.
http://bearingsdirect.com/store/inde..._detail&p=4212
04-15-2010, 03:29 PM
#20
AudiWorld Member
Thread Starter
Well, first off that's really cheap for ceramic bearings - check the country of origin......
Secondly, you don't need bearings this good, but you'll never have to replace them again, that's for sure! Only one thing bother's me.....metal shielded bearings are that way because they're meant to be regreased, and there is no way to do that on this little motor except to take it apart again. Sealed bearings usually have plastic seals instead of metal. That wouldn't stop me from using them tho!
Let us know what you decide to do, and good luck on your repair!
Secondly, you don't need bearings this good, but you'll never have to replace them again, that's for sure! Only one thing bother's me.....metal shielded bearings are that way because they're meant to be regreased, and there is no way to do that on this little motor except to take it apart again. Sealed bearings usually have plastic seals instead of metal. That wouldn't stop me from using them tho!
Let us know what you decide to do, and good luck on your repair!