Combining two layers to create one solid object and remove white line

[rusty5D64]

I've got a stubborn problem I can't figure out for the life of me, guys. 

I've got this logo that I want to be one solid object with as few paths as possible, but I've got this divided section that I can't figure out how to combine. Mergine it, joining it, compound path hasn't solved it - but I'm sure I'm doing something wrong. When I save it out as a PDF or EPS it has a white line through the two elements and it's driving me insane.

Help...

Thanks!

[Monika Gause · Accepted solution]

Just use the shapebuilder tool if nothing else works.

Turn on the gap detection in the tool.

Please embed screenshots in your posts, don't attach them.

[rusty5D64]

THANKS Monika. That worked immediately and perfectly! Bingo. 

OK - sorry about the non-embed. Rookie move. 

Appreciate the help!