How do i re thread the spool on a black and decker gl320

Page 8 of the user manual. If you do not have the manual, you can download it from here: http://www.manualslib.com/manual/16674/Black-And-Decker-Gh710.html?page=9#manual

with fine file , refurbish male threads.
determine the female threads with magnifying glass to determine damage to female threads. female threads can be repaired with a die from OSH or H/D. ask for help to find the right thread pattern or take them both to the hardware store to get the right die

There is a tiny hole where you must put the string through in the spool. Then hold it there with your finger and start wrapping the way it shows on the top of the spool.

Remove cup from bottom of unit by depressing 2 detent tabs and pulling away from unit.
Replace empty spool with new full one or wind on aftermarket string. Wind in direction of
arrow on spool. Make sure spool is seated on rachet firmly.

For Black and Deckers: Remove cup from bottom of unit by depressing 2 detent tabs and pulling away from unit. Replace empty spool with new full one or wind on aftermarket string. Wind in direction of arrow on spool. Make sure spool is seated on rachet firmly.

For Black and Deckers: Remove cup from bottom of unit by depressing 2 detent tabs and
pulling away from unit. Replace empty spool with new full one or wind on aftermarket
string. Wind in direction of arrow on spool. Make sure spool is seated on rachet firmly.
MANUAL:
http://www.dewaltservicenet.com/servicenet_home.aspx?AspxAutoDetectCookieSupport=1

PARTS:
http://www.ereplacementparts.com/black-and-decker-grass-trimmer-parts-c-4167_9518.html

Make sure to look at the spool. There should be an arrow showing which way to wind the string...Good luck...Lee

Go to home depot. look at the floor model and the replacement spools they sell there. Reverse engineer the stringing process or but a pre-loaded spool.
Otherwise,
1. Squeeze the tabs on the side of the head of the unit to remove the spool cover.
2. remove spool.
3. place end of string in small hole in center ring of spool.
4. wide spool with string in the direction of the arrows printed on the spool. DO NOT OVERLOAD!.
5. snap string into notch on spool and cut string leaving 6" exposed.
6. thread 6" of string through hole in side of unit head, replace spool, and replace cover.
7. go cut grass.

Do you mean that the string keeps feeding as you try to operate the trimmer?

If so, you are winding the string on the spool the wrong way. Put the string on the spool in a clockwise direction. This should do it.

Jim

rethread grasshog