Chevrolet 70 1969 Series, Shop Manual

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POWER BRAKE 5-58
m ay be necessary to tap governor body flat against
work bench to dislodge piston.
6. Remove two piston grom m ets from grooves in piston.
Discard grom m ets.
7. Remove valve spring, valve, exhaust stem, and ex­
haust stem spring from piston.
8. Remove exhaust stem grom m et and washer from
bore. Discard grom m et.
9. M ount adjusting screw and spring assembly in a vise
with soft jaws.
10. Remove lock nut from adjuster screw; then thread
adjuster screw out of upper spring seat.
11. Remove spring, lower spring seat, spring guide, and
second lower spring seat from adjuster screw.
CLEANING AND INSPECTION
1. W ash all m etal parts in cleaning solvent. Blow parts
dry. W ipe rubber parts dry.
2. Check valve spring, exhaust stem spring, and adjuster
screw spring for free length, active coils, or collapsed
coils.
3. Inspect governor body for cracks, nicks, burrs, or
other dam age. Check for crossed or stripped threads.
4. Inspect adjuster screw for crossed or stripped threads
and distortion.
5. Exam ine the piston for nicks, burrs, or other dam age.
6. Check governor valve for deterioration or other d a m ­
age.
7. Exam ine the two filters in governor body. If d a m ­
aged, use a sharp hooked tool and remove them. Use
a suitable sleeve; press new filters in governor body
ports.
8. Inspect all air passages in ports for obstructions.
ASSEMBLY (Refer to Fig. 26)
Prior to assem bly of governor, lubricate governor body
bore, top of piston, piston grooves, piston grom m ets,
Adjusting Screw
Retaining
Upper Spring
Sea
Pressure Setting
Spring
Cover
Lower Spring
Seats
G ro m m e ts^
Adjusting Screw
Lock Nut
Body
Spring Guide
Exhaust Stem Spring
Exhaust Stem
>Filters
Inlet and Inlet-Exhaust Piston
Exhaust Valve Valve Spring
F igu re 2 5 — T y p e " D - 2 " A ir C o m p re sso r G o v e rn o r
spring guide, and adjusting screw with a barium -base
grease.
1. Position first lower spring seat, spring guide, second
lower spring seat, and spring on adjuster screw.
T hread adjuster screw into upper spring seat until the
dim ension from the top of the seat to the bottom of
the stem head is 1 - 7 /8 inches as shown in Figure 27:
then m ou nt adjuster screw and spring assem bly in a
vise having soft jaws.
Install lock nut on adjuster screw.
Position new exhaust stem g rom m et in groove inside
piston. Install new washer in piston. Prick punch
washer in four places.
Install two new grom m ets in grooves on outside of
piston.
6. Position exhaust stem spring, exhaust stem, valve,
2
.
3.
4.
5.
1 R u b b e r C o v e r
2 C o v e r R e t a i n in g R i n g
3 L o c k N ut
4 U p p e r S p r i n g Seat
5 A d j u s t e r S c r e w S p r in g
6 L o w e r S p r i n g Seat
7 S p r in g G u i d e
8 L o w e r S p r i n g Seat
9 A d j u s t e r S c r e w
1 0 Piston G r o m m e t
11 E x h au st Stem
12 E x h au st Stem Spring
13 W ash er
14 E x h au st S tem G ro m m e t
15 Piston
16 Valve
17 Valve Spring
18 Piston G ro m m e t
19 G o v ern o r Body
tpm
9398
Figure 2 6 — Type " D - 2 " Governor Com ponents
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L