Hi,
I have no connection to the surname Erdmann- but wanted to offer this:
1920 Cook Cty., IL, Enumer. Dist. #2077, Sheet 2B, 2211 Keystone: Erdmann, Emil (61), Amalia (55-wife). They state they immigrated in 1889 and were naturalized in 1900. They were both born in West Prussia and he was a tailor.
Are you sure your Emil Erdmann died in 1914? Because this guy fits the profile! Of course, wife's name is different though.