broken or distorted, and when new linings are
(7) Inspect inlet connection block bore where
installed to replace worn out linings. Replace all
O-rings seal for scratches and grooves.
twelve springs to insure uniform retraction.
(8) Inspect brakedrums for cracks, checks,
e. Reassembly. Refer to figure 3-108 and
d i s t o r t i o n , and scored surfaces. Scored brakedrums
reassemble the brake assembly as follows:
can be repaired by turning on a lathe. No brake
( 1 ) Install two new O-rings (3 and 4) on ex-
l i n i n g is any better than the drum it contacts. The
pander tube nozzle (12), lubricating them with
maximum brakedrum should be turned is 0.060 to
vaseline, and install inlet connection (10).
(2) If torque plate (11) has been removed from
(9) If any linings have come loose from the
axle housing, install with opening at top. Slide
shoes, re-rivet them.
expander tube (12) with inlet connection over the
(10) If the frame assembly is cracked or
(11) Recement expander tube shields. If any
Be sure that the inlet connection
shields are loose, all shields should be removed and
opening faces the vehicle, and that the
reversing the block
inlet connection drum bolt clearance
a s s e m b l i e s from their original installation. Procure
n o t c h faces the wheel side of the torque
a good neoprene base adhesive compound and use
( 3 ) Position lower half of frame (9) over ex-
(a) Clean shields with lacquer thinner or
p a n d e r tube and torque plate (11), and secure with
acetone. Do not use petroleum base solvents.
bolts (1). Tighten bolts 3/8"-38 to 42, ½"-95 to
(b) Place one shoe in brake assembly.
100, 5/8''-l70 to 185 ft.-lbs. torque; dry thread.
Reverse shoe to expose a clean section of tube, free
from initial cement. Mark the position of the ex-
tended end of the shoe on the tube. Note the
If necessary to line up frame bolt holes, start at one
position of the m ark in relation to the torque bar of
end and install five bolts; then install a clamp across
the frame to line up the last two holes, and install
the frame assembly. Mark relative positions for
(c) Coat cement on the tube at each of the
(4) Position upper half of frame (8) over
twelve marks. Coat a spot 3 x 1½ with the 1½ inch
expander tube and torque plate, making sure that
dimension being centered over the mark. The 3
i n l e t connection lines up with frame cutout. Install
inch dimension should be centered between the
b o l t s . Tighten bolts 3/8"- 3 8 t o 4 2 , ½ " - 9 5 t o 1 0 0 ,
5/8''-l70 to 185 ft.-lbs. torque; dry thread.
( d ) Coat the inside, or concave side, of the
(5) Place a block and shoe assembly (5),
shields with cement. Keep cement confined to the
between the torque bars so that projecting end of
center 3 inches of the shields.
shoe is approximately centered on a shield (6).
(e) A l l o w c e m e n t t o d r y f o r 5 m i n u t e s .
P a r t i a l l y insert retracting spring (6) to temporarily
(f) Place a shield on the tube so that one half
hold the lining assembly in place.
o f the shield protrudes from under the end of the
( 6 ) Dovetail a second block and shoe assembly
i n t o the first block and shoe, and partially insert a
(g) Remove the shoe assembly and press
s e c o n d retracting spring. Drive the first spring fully
shield firmly to the tube.
(h) Install the next shoe with a shield
(7) Install remaining block and shoe
centered under the protruding end of the shoe.
a s s e m b l i e s in similar manner, that is, always keep
Press shield firmly to tube and install retracting
o n e shoe assembly ahead of the one in which the
retracting spring is being completely inserted.
(i) C o n t i n u e i n s a m e m a n n e r w i t h t h e
b a l a n c e of the shields, shoes and springs until all
(1) Refer to figure 3-108 and reinstall the
brakeshoes and shields are in place.
b r a k e assembly. Reinstallation is the reverse order
(12) Replace expander tube if cracked,
charred, or if the nozzle is loose.
(2) Replace wheel (TM 10-3930-242-12).
( 1 3 ) Replace brake lining if worn beyond the
minimum thickness if torque bar forms ridges on
( 1 ) Fill reservoir with hydraulic oil (OE 10).
the end face of the linings that may cause the block
and shoe assemblies to hang up, or if excessive
Reservoir must be free of dirt. A screen should be
cracking or chipping is evident.
provided in the reservoir to keep out foreign particles.
( 1 4 ) Replace the frame assemblies if distorted
from any crack or damage.
(2) With engine idling, open each bleeder
valve (located on top of automatic slack adjuster
(15) Replace retracting springs if they are