Pull off the plastic cog on the left and remove
the bearing inside the spool. Remove the circular spring clip that holds the
brake assembly (two little plastic blocks mounted on arms on a circular washer,
far right of the picture), remove the brake assembly and then remove the bearing
from the spool, there should be a
small copper washer behind this bearing, don’t lose it!

Put each bearing on something
you can use to spin it on, then put a few drops of lighter fuel on the
bearing. Spin the bearing until you hear it running freely. Then dry it in a
piece of kitchen towel. Repeat for the other bearing.
If
you have a UC reel the bearings are captive on the axle with the spool. Apply
the lighter fluid to the bearings on the spool in the same way.

Once the bearings are
completely dry and all the lighter fuel has evaporated apply one, or at most 2,
drops of oil to the bearing and spin them to ease the oil into the bearing.
Then reassemble the spool.
Don’t
use WD40 oil for this job as it will coat the bearings with some sort of
varnish and the bearings will make nasty noises and need replacing!

Next apply some of the reel oil to the level wind
worm gear, which is the criss crossed part you can see from underneath.

On C4 models there is a bearing at the end of the
level wind shaft, which should be oiled as well. There is a plastic bushing on
other models which can be oiled too.

Finally, put a drop of oil on the double plastic
cog in this picture. Put the oil on the end of the axle that it’s mounted
on. This is not strictly necessary, but does no harm.

Wipe round the inside of the circular chrome
piece on the gearbox to remove any oil or grease deposits.

Make sure the little plastic blocks are pushed
in, as they slide in and out on the little arms they’re mounted on.

Then reassemble the gearbox onto the rest of the reel. Don’t
force anything. If it won’t close up that final bit it’s probably because
one of the brake blocks isn’t pushed in fully.
Congratulations! Your reel is good for a few thousand more
casts. It wasn't too painful was it?