I just got done installing my Johnson CM30 to replace the ailing stock Bosche pump. After a reasonably long drive, I'm starting to think my new pump may not be working at all. How imperative is it that you bleed the system after replacing the pump? The Johnson pump doesn't have the third small nipple for what I'm assuming is a bleed/vent line like the stock pump does. Is this something I can do without? My next plan of attack is to use a multimeter to determine whether the pump is actually running or not. If anyone has any pointers on the subject, I'm all ears. Driving an "N/A" SL55 sucks.

The CM30 didn't work well for my car either.

I went with the stock OEM updated pump from my dealer.

I know it works because I have the fastest stock SL55 on dragtimes.com.

Check you wiring and get a scanner to see your IAT's.

I believe you must bleed the pump. Here is a link that might be helpful: https://mbworld.org/forums/w211-amg/216325-diy-ic-pump-e55.html

An NA 55 kompressor is no fun at all.

Good Luck