
25 Hydraulic brake systems
25.1 BRAKE SHOE ARRANGEMENTS
General background
The earliest and simplest form of hydraulically oper-
ated, internally expanding drum brakes is that in which
a pair of friction-lined shoes is mounted in leading and
trailing fashion on either a common or individual pivots.
Before the layout of this type of drum brake assembly is
examined in detail, it must first be briefly explained
what is meant by the expressions leading and trailing
shoes (Figure 25.1).
A leading shoe may be defined as one where the
direction of drum rotation is from the applied load end
or toe to the fulcrum end or heel. Conversely, a trailing