Empty "L" Bracket Housing for 12 Day Fleck 5600. # 1549401
If your Valve is the Econominder Version then use part number 3415494 instead ( listed below ).

If your housing has broken, you can transfer the gears and timer motor to this new empty case. Not much fun, but do able.
For a quick and easy repair, order the complete power head listed below.
And if your Valve is over 20 years old, then a complete valve replace might be your best bet.