If our center consoles are the same,( my 300cd), there is a bracket under the ash tray with a spacer under it. Place the spacer so when you just start to get the bracket snug ( so to not put too much pressure on the front end as to cause a bend it in the middle which might cause cracking) while pushing forward on the back of the center console to engage the keeper pin.

As for the carpet wash it in the washer but let it air dry unless you have a wool setting on your dryer.

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1990 420SEL
1995 E320 Coupe
2000 SL500
2009 ML320