One way to get glue into tight places is to use glue injectors. You can actually buy injectors that are made for glue, or sometimes make ones out of anything from cooking tools to medical supplies.
To make glue flow easier while maintaining its strength, don't dilute it but warm it up in a pot of hot water, just like a baby bottle.
Glue injectors and applicators can be found in fine woodworking stores or mail order catalogues, but rarely in regular hardware stores.