Jbrew-Greetings. You might be experiencing "chugging" or backing difficulties. Try this online manual of the three most common trailer brake types.
http://www.ufpnet.com/Selecte actuators and then the middle of the three options. Page 19 is the trouble shooting phase.
In general the emergency release is reset at the ball hitch end but without knowing your trailer it's difficult to diagnose. The manual may help.
Thanks for asking.
Scott
Marine Engineer
MEC3 and RYA Yachtmaster Ocean