A few notes to others who may try this .
I found it very difficult to remove the motor faceplate gently.I did squeeze the stakes as Qmulus kindly suggests below. It went easier when I ground back the obstructing 'ears' and edges. Remove only as much as is necessary. There are 2 Torx screws that help secure the front plate so I was not worried about reassembly with slimmed down stakes.
I was worried about damaging the carbon brushes so removed the springs- that was fun replacing them !I used an Exacto blade to hold them compressed in position while bending back the 4 retaining tabs.
The bearings are(?) 608 2RS .2RS Not ZZ ! I measured the o.d. as 22mm, the i.d. as 8mm and the thickness as 7mm.As Qmulus suggests, this is a popular size for skateboards but better quality are available- even ceramic on Amazon!
The bigger problem is the stakes around the mid point of the circumference of the body of the motor. They are very thick.I had no way of bending them without risking damage & debris inside the motor. Perhaps they could be weakened with a Dremel wheel and then bent out of the way? Q was right ,there was carbon debris so I removed what I could with a powerful shop vac.
My suggestion is that if the motor is noisy - find a replacement motor - but where? It has no part number or manufacturer name on it. Must be available because the same motor is used on many other vehicles.
WRITEUP: 2.7T Secondary Air Injection SAI Pump rebuild - AudiWorld Forums
Maybe the VW/Audi?Mercedes Forums have solved this issue??
Reassembly - you may need pushnuts - the 3 that retain the filter housing? Here is a possible source Aaronspushnuts. FYI ,they are approx. 12mm o.d. and 2mm i.d.:
** PUSHNUTS, push on nuts for bolts or unthreaded rods **
There is also an External circlip 15mm i.d. I do not know what function it has other than to make a scraping noise. Chucks Pump was missing this part but worked fine w/o it.
Quote:
Originally Posted by Qmulus
"For disassembling the pump motor, I squeeze the "ears" that were peened over back up, then use a flat chisel to work the end plate off of the motor housing. Doing it this way you can then peen the ears back down when you are done with another sharp chisel and it looks like no one was even there. If you grind away the ears, you have no material to keep the end plate on.
The actual process of rebuilding these pumps correctly is an involved and messy process. First you disassemble and clean everything (an industrial washer and or ultrasonic cleaner is ideal), then test the armature windings, turn and properly finish the commutator and brushes, replace bearings, reassemble and test for some amount of time (note current and airflow) . There are also some other steps that I consider "proprietary" that I learned from experience on these, but that is basics. This all assumes the motors are in good shape, when in reality about 50% have damaged windings and/or are badly corroded from exhaust gases. I don't bother with those, but they could be repaired. Luckily the orientation of the pumps in the Porsches (horiontal) is more favorable to these pumps than the vertical orientation used in other cars as the carbon from the brushes is not as likely to settle on the bearings. A brushless motor in this application would be ideal.
Anyway, glad to hear that you found your issue.
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