I just did this on my 300SDL too!! Where did you get your motor? I got mine at thebenzbin.com for I think $70.. they are pretty cheap if you need parts in the future.. But I priced a new assembly and it was around $250.

To get the blower off the shaft. i placed the blower between two tables and used a center punch to push the motor out of the blower. I did the same to bang the motor out of the housing.

After I bought my new motor, I decided I would try to fix the old one, I took it apart, and sanded the commutator, and still had about 1/8" of brushes left, so I put it all back together with the old motor and it works.. I think I will keep my new one as a spair.

John