You’ll also want to detach the metal ground strap located
in the center of the terminal block, where the neutral/ground
wire was connected. This metal strap has been used to ground
the dryer by connecting the neutral wire to the body of the dryer.
A separate ground wire—the fourth wire, is replacing it.
You should be able to simply remove this metal strap.
The new cord has a green ground wire; two hot wires, which
are black and red; and a white neutral wire. Attach the neutral
to the middle connector and the two hot wires to either end of
the terminal.
In order to safely ground the machine the green
ground wire must be securely connected to the dryer frame.
There may be a screw on the frame where you can attach the
ground but most likely you’ll have to drill a hole into
the frame and attach the wire using a sheet metal screw and
washer.
To make sure the ground wire is properly installed
you can check it using a multimeter set to test resistance.
Touch one end of the multimeter to the metal body of the dryer
and the other to the ground prong of the plug. The meter should
register a positive resistance reading. If it doesn’t,
double check to make sure you’ve made a good connection
between the dryer frame and the ground wire.
Replace the metal access plate carefully; the new ground wire will
protrude from the side of the plate as it is attached to the outside
of the dryer frame. The plate should fit snugly without cutting
into the new ground wire.