SAI Repair DIY
01-14-2013, 02:08 PM
#1
Drifting
Thread Starter
SAI Repair DIY
This is a relatively easy DIY that may save a failing secondary air injection motor, commonly referred to as the SAI. Removal and installation is easy and covered many times elsewhere, so I wont repeat it. I would only do this repair if I heard the tell-tale screech/squeal on SAI start-up. The noise is indicating the SAI has a problem anyway, whether its the bearings or fan discs, the unit may need service soon. The noise could be from the sealed bearings or fan discs.
After SAI removal, separate the mounting bracket from the SAI assembly.
Remove retaining clips from assembly case.
You can now see the motor shaft and fan discs retaining nut. Don’t remove the snap ring. Just remove the nut.
Remove all fan discs and spacers, carefully noting the order and position of each piece. I usually stack or lay the pieces in order so I don’t forget. You may want to photograph or make notes.
You should now see only the motor left in the motor case. Remove the two retaining screws.
Replace the retaining nut on the motor shaft and carefully secure in a vise. Gently pull the motor case from the motor. You will see that it is just a basic rotor/stator electric motor.
You can now see the sealed bearings on each end of the electric motor. The shaft end and support end.
Carefully remove the seal from the SHAFT END sealed bearing. I used a jewelers flat blade screw driver to remove the seal. Just be gentle with it and it wont break.
You can now see the exposed caged ball bearings. Mine were dry. I carefully packed the bearings with a lite quality grease while rotating the shaft. I then replaced the seal and verified it was seated. The seal cant come out later because a spacer rides against it.
Then look at the support end sealed bearing. You will not be able to remove the seal but you can carefully separate it enough to “inject” grease into the bearing. You can use a needle-tip adapter on your grease gun or a large gauge syringe (18g or 20g) with lite grease.
I even put a little extra grease on the support end of the shaft because it is isolated in the closed housing end.
Verify the motor turns smoothly, reassemble, and install. You can test it prior to installation with a 12V DC source if you want to.
Some miscellaneous notes:
This will probably not help a seized sealed bearing(s).
This is NOT a critical complicated engine part and is not hard to DIY if you take your time and carefully note the dis-assembly.
I will run mine for awhile then take it apart again and see if my “extra” grease attracted more dust or dirt.
If my bearings would have been ruined, I still would not have trashed the unit. I would have rebuilt the electric motor itself, replacing the brushes and bearings which is much harder than this DIY.
After SAI removal, separate the mounting bracket from the SAI assembly.
Remove retaining clips from assembly case.
You can now see the motor shaft and fan discs retaining nut. Don’t remove the snap ring. Just remove the nut.
Remove all fan discs and spacers, carefully noting the order and position of each piece. I usually stack or lay the pieces in order so I don’t forget. You may want to photograph or make notes.
You should now see only the motor left in the motor case. Remove the two retaining screws.
Replace the retaining nut on the motor shaft and carefully secure in a vise. Gently pull the motor case from the motor. You will see that it is just a basic rotor/stator electric motor.
You can now see the sealed bearings on each end of the electric motor. The shaft end and support end.
Carefully remove the seal from the SHAFT END sealed bearing. I used a jewelers flat blade screw driver to remove the seal. Just be gentle with it and it wont break.
You can now see the exposed caged ball bearings. Mine were dry. I carefully packed the bearings with a lite quality grease while rotating the shaft. I then replaced the seal and verified it was seated. The seal cant come out later because a spacer rides against it.
Then look at the support end sealed bearing. You will not be able to remove the seal but you can carefully separate it enough to “inject” grease into the bearing. You can use a needle-tip adapter on your grease gun or a large gauge syringe (18g or 20g) with lite grease.
I even put a little extra grease on the support end of the shaft because it is isolated in the closed housing end.
Verify the motor turns smoothly, reassemble, and install. You can test it prior to installation with a 12V DC source if you want to.
Some miscellaneous notes:
This will probably not help a seized sealed bearing(s).
This is NOT a critical complicated engine part and is not hard to DIY if you take your time and carefully note the dis-assembly.
I will run mine for awhile then take it apart again and see if my “extra” grease attracted more dust or dirt.
If my bearings would have been ruined, I still would not have trashed the unit. I would have rebuilt the electric motor itself, replacing the brushes and bearings which is much harder than this DIY.
Last edited by KrazyK; 11-20-2014 at 06:25 PM.
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01-14-2013, 05:58 PM
#3
Excellent job Krazy - detail in your instructions is really good - a true "how to" for each step - for example rather than just saying "remove the motor from the case" - you actually tell us how.
Thank you - (now don't get all mad at me if by chance mine requires SAI work in the future and I don't do it by myself - what I will be armed with though is the knowledge that this part is not something that only a NASA engineer can work on)
Thank you - (now don't get all mad at me if by chance mine requires SAI work in the future and I don't do it by myself - what I will be armed with though is the knowledge that this part is not something that only a NASA engineer can work on)
03-23-2013, 02:10 AM
#7
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Thank you!
KrazyK,
Thanks so much. I had the loud whine noise followed by a wobbly wah wah wah when the SAI shut off. I followed your instructions to the letter and the noises are completely gone. I did take the liberty of spraying out every individual part with compressed air including the filter on the end which I also disassembled. There was a lot of dust in that small part! I used multiple applications of WD40 to clean out the bearings then used 3 in 1 oil to lube as I did not have grease and it was after 10 pm when I started the project so no stores were open... I will monitor it and if the noise returns I will disassemble again and use grease. Thanks again.
Thanks so much. I had the loud whine noise followed by a wobbly wah wah wah when the SAI shut off. I followed your instructions to the letter and the noises are completely gone. I did take the liberty of spraying out every individual part with compressed air including the filter on the end which I also disassembled. There was a lot of dust in that small part! I used multiple applications of WD40 to clean out the bearings then used 3 in 1 oil to lube as I did not have grease and it was after 10 pm when I started the project so no stores were open... I will monitor it and if the noise returns I will disassemble again and use grease. Thanks again.
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03-23-2013, 10:58 AM
#8
Three Wheelin'
That one is identical to audi 2.7T SAI pump by the way
Write up I did years ago:
http://forums.audiworld.com/showthread.php?t=1727056
Write up I did years ago:
http://forums.audiworld.com/showthread.php?t=1727056
03-26-2013, 11:01 PM
#9
By SAI was screaming whenever I started up the car cold. I cleaned it out this winter thanks to these instructions. It was pretty straightforward.
I used an air-compressor to blow out (a lot) of dust from the motor, and cleaned and inserted teflon grease into the bearings.
Cleaned and reinstalled. The startup noise is gone.
I used an air-compressor to blow out (a lot) of dust from the motor, and cleaned and inserted teflon grease into the bearings.
Cleaned and reinstalled. The startup noise is gone.
