GMC 4000 Series Service Manual page 255

Sec. 5B
Page 248
AIR BRAKES
or by putting pressure housing in vise and using
a wrench on hex end of cap.
4. Position diaphragm over plate rod, then in­
stall pressure housing and cap assembly.
NOTE: Diaphragm should fit evenly between
pressure housing and non-pressure housing. Align
marks made on housings at disassembly to insure
proper air port location.
5. Pull clamping ring over flange of pressure
and non-pressure housings. Install clamp bolt and
nut and tighten firm ly.
*A ir brakes are optional equipment on LA, DLA4000. Standard brakes are Air-
( * ) With Eaton 16121 or 16221 opt. axle.
( f ) Includes L, DL4000 with Tim ken G161 or G361 opt. axle.
* " Fail-S afe " cham bers are optional on all 5500-6500.
G M C S E R V I C E M A N U A L
SPECIFICATIONS
FRONT BRAKES
FRONT AXLE MODEL
Brake S iz e ................................................................................
Brake Shoe Lining
W id th ......................................................................................
T h ic k n e s s ..............................................................................
Area (sq. in. per a x le ) ........................................................
Brake Chamber
T y p e .......................................................................................
Diam eter................................................................................
Adjust Travel to ...................................................................
Slack Adjuster
T yp e ........................................................................................
Length Between Hole C e n te rs...........................................
Assisted Hydraulic.
REAR BRAKES (EXCEPT STOPMASTER)
TRUCK SERIES
Brake S iz e ............................................
Brake Shoe Lining
W id th...............................................
T h ic k n e ss.......................................
Area (sq. in. per a x le )....................
Brake Chamber
T y p e .................................................
D iam eter.........................................
Adjust Travel t o.................................
S lack Adjuster
T y p e................................................
Length Between Hole Centers.
STOPMASTER BRAKE SPECIFICATIONS
TRUCK SERIES
Brake S iz e .................................................................................
Brake Shoe Lining
W id th.....................................................................................
T h ic k n e ss..............................................................................
Area (sq. in. per a x le )........................................................
Brake Chamber
Standard
Diameter (at clamp b a n d ).............................................
" F a il-S a fe "
Diameter (at chamber b o d y).........................................
. Connect all air lines and build up air p res­
6
sure in system to normal operating pressure. Push
parking brake knob in to admit air to outer brake
chamber.
7. Turn release bolt counterclockwise as far
as possible (approx.
18
(see fig. 42). This will leave the parking brake
chamber in operating condition.
NOTE: It is best to have at least 60 psi of air
in chamber to hold spring tension off nut so a bet­
ter "feel" is obtained when the nut does bottom.
*F070
1 5 x 3
3"
/ 6" 7
i
190
52 3 /32"
Short as possible
w /o brakes dragging
PL-18
W - W
L, DL4000(*) ALL MODELS(f)
1 5 x 6
15 x 5
6"
5"
3 /4"
3 / 4 "
316.8
24 24
l l A "
m *
Short as possible w /o brakes dra
PL-24
PL-20
6"
5 /2"
5500— OPT
6500— STD
15 x 5
5"
Crescent
315
5.66"
5.264"*
turns) to release spring
12