Chevrolet 70 1969 Series, Shop Manual

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POWER BRAKE 5-37
B U S H I N G \ R E T A IN E R \ P L U G
V A L V E B O D Y
T 1 8 2 4
Figure 9— Unloader Assembly
tate bearing by hand
L o
detect roughness. If wear,
roughness, or dam age is evident, bearing m ust be re­
placed.
CRANKCASE
1. Exam ine crankcase for cracks or other dam age. R e­
place with new part, if dam aged.
2. Inspect studs in crankcase and replace any which are
bent or have dam aged threads. W hen replacing studs,
be sure and install studs of proper length in same
holes from which they were removed.
CRANKSHAFT BEARING CAPS
E xam ine crankshaft front and rear bearing caps and re­
place if cracked. Check inside diam eter of rear bearing
against dim ension listed in “ Specifications” at end of this
m anual. Replace bearing cap assem bly if bearing is appre­
ciably worn (bearing only, is not serviced separately).
UNLOADER (Refer to Fig. 9)
1. Rem ove bushing, disc, diaphragm , and expander
spring from body. Should difficulty be encountered in
removing these parts, apply light air pressure to body
to force out these parts.
2. Remove rubber retainer from bushing.
3. Apply a thin film of light engine oil to bushing, dia­
phragm , and body before assembly.
4. Install expander spring around inside of diaphragm ,
then install these two parts in body.
5. Install rubber retainer on bushing.
6. Place disc in recess of bushing, then install in body.
GOVERNOR
There are two types of governors; the lock nut retained
housing type and the setscrew retained housing type. They
do not differ in their m ajor assemblies, but only in the re­
taining of the housing in governor body. Refer to Figure
10
.
Overhaul
1. Loosen adjuster plug lock nut, then remove adjuster
plug, spring and spring guide.
2. Remove large hex nut or the plug and set screw re­
tainers from housing and body.
3. Remove housing from governor body. R em ove hous­
ing O-ring. Rem ove valve assembly.
4. Rem ove end cap, and filter from governor body.
Clean and inspect governor assembly.
1 Adjuster Plug
2 Plug Lock Nut
3 Housing 4 Governor Body
5 Expansion Plug
6 Setscrew
S E T S C R E W R E T A IN E D
HO U SIN G T Y P E
7 O-ring
8 Spring
9 Spring Guide
L O C K N U T R E T A IN E D HOUSING T Y P E
1 Adjuster Plug
2 Plug Lock Nut
3 Spring
4 Spring Guide
5 Housing Lock Nut
6 Housing O-ring
7 Housing
8 Valve Assembly
9 Governor Body
10
/
10 Filter
11 End Cap
T - 4 3 9 1
Figure 10— Governor Com ponents
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M A N U A L