I didn't think it was possible for the Wrench Guy to help you until you collected all three red wrenches, but I guess this is a bug on the Android version.
The Wrench Guy will help you even if you haven't gotten the other two wrenches. =o)
i got the wrench on the wall and the wrench in the book and then gave the wrench guy his music. i didnt get the wrench from the drain...
If you've only gotten the wrench from the book and the wrench off the pipes, the Wrench Guy is supposed to spit out the third wrench right after removing the cap.
So yeah, it sounds like a bug. =o(