BRAKES-AIR
TRUCK SERVICE MANUAL
Fig. 1 Foundation Brake Assembly
Various tools are available which assist in
DESCRIPTION
servicing brake systems. These tools are Brake Recliner
(SE-1272), which is designed to remove, drill, rivet and
The foundation brake is where the real work in
circle grindlining, Shoe Gauge (SE1572) to measure arc
stopping a vehicle takes place. To provide adequate
diameter, determine from old shoe the diameter of drum
brakes on a vehicle, every square inch of brake lining-to-
the shoe has been working in and thickness of lining to
drum contact is needed as well as overall condition of
use in order to insure same arc diameter of drum. Brake
the frictional surface of the drum.
Drum Checker (SE-1605) to measure brake drum.
Brake shoe Grinder (SE-1690) used to circle grind or
The term foundation brake is given to those
grind lining on shoes in a true radius.
components at wheels which actually do the braking.
This includes such items as brake shoes, lining, anchors,
DISASSEMBLY
drums and spider or backing plate, Fig. 1. Although the
slack adjusters, cam and followers are not directly known
as components of the foundation brakes, they will be
Variations in the disassembly procedure may be
covered herein.
required as different types of brakes have been used on
IH vehicles. Some typical brakes used are single and
The following paragraphs cover the step-by-step
double anchor as well as wedge type actuated brakes.
procedures in servicing these components.
To disassemble the wheel brakes, proceed as
The need to be properly equipped in order to
follows, referring to the exploded view of that particular
perform "quality" brake service is greater now than it ever
brake group. Fig. 2 illustrates ' a typical front brake
was because of the fine tolerances of brake systems.
group while Figs. 3 and 4 illustrate typical rear brake
groups.
The key to precision brake service is in the
machine or truing every brake drum and fitting new brake
NOTE: More detailed information covering various
lining and shoe to the new drum diameter.
components can be found elsewhere in this section.
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