Here is the excerpt from the L322 Workshop Manual

Adjust
1. Raise rear of vehicle.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
2. Remove rear road wheels.
3. On each rear brake:
4. Remove adjuster access plug from brake disc.
5. Rotate brake disc until access hole is in the 6
o'clock position.
6. Using a screwdriver or similar tool, turn brake
shoe adjuster until resistance is felt. Apply
handbrake several times to centre shoes, re-adjust
if required and repeat.
7. Ensure handbrake is released and check disc
will not rotate.
8. Back the adjuster off 8 notches, check disc is
free to rotate.
9. Fit adjuster access plug.
10. Fit rear road wheels and tighten nuts to 140 Nm
(103 lbf.ft).
11. Handbrake lever assembly is self adjusting and
will correctly tension cables. However after
adjustment apply handbrake several times,
release handbrake and ensure road wheels are
free to rotate.
12. Lower vehicle.

Click image to enlarge