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Discussion Starter · #1 ·
I removed the Secondary Air Pump on my 2005 SLK 350. Mine turned out to be OK but here is how to do it. It is not difficult but I found angle Torx wrench very handy, you can use a narrow spark plug socket and extension to place over the end if you need more torque. The motor is attached on a bracket with 4 screws that need to be removed. Only the left side inner one was a bit tricky. I wrapped a plastic electronic bundle harness once I had it loose so I didn't drop it when pulling out, really helps to position for putting back in too, just cut the plastic once the screw is threaded. All the screws had an initial hold but would suddenly release with a little snap and then were easy to unthread.
Both screws on right are easily accessable (first picture shows where they were) and the far one on the left (#4) but the one just behind and above the belt (#3) is tricky but look at the picture. There is a screw right above that secures the solenoids separate bracket (black colored) to the motors bracket (not painted), you can leave this alone.
Once the bracket is free its easy to remove the 3 screws holding the motor to the bracket, don't forget to pull the power lead, its the only electrical connection you need to remove.
Also be careful its easy to knock off those small hoses going to the solenoid on the far left, make sure they are all connected before replacing motor. I knocked one loose.
I could have left the motor and tested it in situ but I read sometimes if the casing loose you can get fooled so I chose to take it out, connected to a separate car battery with thick leads and alligator clips. It spun up fine.
Removal took me 45 minutes, 30 minutes to put it back in.
Of course you will need to remove the front shroud and the three hoses before you do anything.
Good Luck!
 

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Discussion Starter · #4 ·
Just a final note here. Replaced old pump with oem bosch pump took 30 min , bought it $200 on Amazon. So quiet, I can't even hear it. This is an easy job, save yourself $1000 +
Anyone have any questions contact me here.


The bearings on mine went at 63,000 mi
 

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**Premium Member 2006 SLK55 AMG
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I had to replace mine a few months ago. My only symptom was a check engine light, followed up with me reading the OBD codes. This is definitely a DIY project. Be sure to use bwessels' suggestion or something similar to avoid lost bolts. I bought my replacement from eeuroparts.com. Here's the link to the part: Mercedes-Benz Air Pump - Bosch 0580000025 - Free Shipping
Less than $200 and shipping is free. I also replaced the associated relay, just in case. My failure was an open circuit through the motor... no continuity.... failed brushes most likely.

Horace
 

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Discussion Starter · #7 ·
what does this secondary air pump do? What were the symptoms that helped you determine it needed replacement?

Also the video you posted has been removed.....

SCF
My pump starting to screech like a jet air plane indicating the bearings were going but I caught it before the seized, then you will have a code issued and warning light. The SAP pumps air into the exhaust/catalytic converters during cold warm up to get the CAT up to operational temperature lowering unwanted emissions. It is a part of the emissions control system and will not effect the engine or running but you won't pass an emissions test w/o it.
Also there have been many cases where as it fails it draws too much current and can ruin the relay and even that whole fuse board under the hood.
 
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