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TRUCK SERVICE MANUAL
TM 5-4210-230-14&P-1
BRAKES-HYDRAULIC
If it is not known how much material has been
removed from the drum during the turning operation, the
following simple test may be used to help select the proper
lining.
Hold standard size lining snugly to the shoe, position
it against the inner surface of the drum, forcing it into contact
with the drum surface. The lining is now in the same position
as during a brake application. If space is noted at the ends of
the shoe (shoe can be rocked), oversize lining is required (Fig.
9). If lining selected is too thick, only the ends of the lining
will contact the drum, see Fig. 10.
Fig. 10 Lining Selected Too Thick
The lining must be installed on the shoe so that it fits
smoothly and evenly, contacting the shoe throughout the
entire radius. If gaps occur between the rivets, difficulty will
be met in adjusting the brakes in that "spongy" or rubbery
pedal may occur which makes satisfactory brake application
impossible.
To insure complete contact and avoid gaps between
lining and shoe, secure lining to shoe with "C" clamp so that
rivet or bolt holes are in alignment. Position "C" clamp as
close to the holes as possible, clamping the lining firmly in
place.
Fig. 11 Sequence in Securing Brake Lining to Shoe
When securing brake lining to shoes, start with the
center rivet or bolt and work toward the ends as shown in Fig.
11. When securing brake block lining to shoe, use the
sequence as shown in Fig. 12. Always use new lock washers
when installing bolt on lining and tighten nuts to 89-111 Nm
(20-25 ft. lbs.) torque.
Fig. 12 Sequence in Securing Brake Block Lining to Shoe
When riveting linings, use a roll set to upset the
rivets. A star set may split the tubular end of rivet and prevent
a tight fit.
After the lining is installed, check tightness of lining
to shoe, (Fig. 13) with a .203 mm (.008 in.) feeler gauge at
any point along the arc of shoe and lining.
Fig. 13 Checking Tightness of Lining
After installing the new lining on the shoes, the lining
should be ground in a true radius to fit the drum diameter. A
brake shoe grinder is provided on brake reliner (SE-1272)
which is designed to dress the lining in a true radius and fit
the drum diameter. This grinder swings the shoe in an arc
across the surface of an abrasive wheel.
A brake shoe grinder which mounts on the spindle
may be used after installing shoes with new lining. The
grinder rotates about on its axis and the grinding head
equalizes the distance between the two brake shoe lining
surfaces
CTS-2779 Page 6
PRINTED IN UNITED STATES OF AMERICA
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