Not sure if it will help, but here are some excerpts from my PV444 service manual:

"Since the brake shoes are flexibly attached to the brake backing plate and because of the shape of the lower support, the brake shoes are self-centering. In addition, the front brake shoes, the linings of which are as a rule subjected to most wear, are self-adjusting.

"The self-adjusting device (fig 3) functions in the following way.

"A contact plug (4) is fitted in a hole in the brake shoe. The outer end of this plug is in contact with the brake drum and is held against this by a spring (2). As the brake lining wears down, the contact plug is moved inwards causing the lever (7) to press against the eccentric (6) by means of a stud (3). In this way the distance between the guide lip (8) on the brake shoe and the toothed lip (9) on the lever (7) is widened. The toothed key (11) which is influenced by a spring (10), is then pulled in between the above lips (8 and 9 respectively). The return movement of the brake shoe is thereby limited so that the clearance between the brake lining and drum remains constant regardless of the degree of wear on the brake lining.

"When the brake linings have worn down so that the contact plug reaches the web of the brake shoe, self-adjusting ceases."

See figure 3 below.

There is then a section called "Adjusting wheel brake units" which states:

"Check the handbrake is not applied. Rotate the wheel backwards and turn the eccentric for the front brake shoe away from the wheel unit cylinder (anti-clockwise on right wheel, clockwise on left wheel) until the wheel is locked by the brake shoe. Then slacken the eccentric sufficiently to enable the wheel to rotate freely (see 2, fig. 20). Adjust the rear brake shoe by rotating the wheel forwards and applying the eccentric in the opposite direction to the front one (see 1, fig. 20)."

See figure 20 below.

Hope this helps.

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58 PV 444