Chevrolet 1977 light duty truck, Руководство по обслуживанию

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ON-VEHICLE SERVICE
G EN ER A L
Exhaust System Pipes and Resonators Rearward of
the Mufflers Must Be Replaced Whenever A New Muffler
Is Installed.
N O T E : W h en a muffler is replaced use sealing
co m pound at the clam ped jo in t to prevent leaks.
T ruck ex h au st systems vary according to series and
m odel desig n atio n . Series 10-30 trucks use a split-joint
design system in w hich the exhaust pipe-to-m uffler are
clam ped to g eth e r and m uffler-to-tailpipe connections are
w elded together. All mufflers an d tailpipes are w elded
assem blies (no clam ps).
N O T E : All 10-20-30 series exhaust systems are
alum inized steel except: (1) " C " Series exhaust
pipes and (2) stainless steel exhaust pipes on
vehicles e q u ip p ed w ith underfloor catalytic convert­
ers. Always use correct rep lacem en t p arts w hen
servicing these systems.
W h e n in stallin g a new exhaust pipe o r muffler and
tailpipe, on any m odel, care should be taken to have the
correct alig n m e n t a n d relatio n sh ip o f the com ponents to
each other. P a rtic u lar care should be given to the
installatio n o f the exhaust pipe and crossover pipe
assem b ly on V-8 en g in e
single e x h au st system s.
Incorrectly assem bled parts o f the exhaust system are
freq u e n tly the cause o f a n n o y in g noises and rattles due
to im p ro p er clearances or obstructions to the norm al flow
o f gases. Leave all clam p bolts and muffler bolts loose
until all parts are p ro p erly aligned and then tighten,
w orking from fro n t to rear.
E xhaust system hangers, h an g e r brackets, and
clam ps w hich are d am ag ed should be replaced to
m a in ta in p ro p e r exhaust system alignm ent.
N O T E : W hen rein stallin g exhaust pipe to m a n i­
fold, always use new packings and nuts. Be sure to
clean m anil'old stud th rea d s w ith a w ire brush
w hen in stallin g the new nuts.
C O N V E R TE R H E A T SHIELD
C 10 Series
R e fe r to F ig u re 6F-1 fo r converter h e at shield.
C A T A L Y T IC C O N V E R TE R (FIGS. 6F-2 and 3 )
C IO and G 10 Series
Removal
1. R aise vehicle on hoist.
2. R em ove clam ps at fro n t and re a r o f converter.
3. C ut co n v erter pipes at fro n t and rear o f
co n v erter and rem ove converter.
4. O n CIO m odels, rem ove support attach in g
converter-to-transm ission.
5. R em ove converter p ip e-to -fro n t-ex h au st pipe
and converter p ip e-to -rear exhaust pipe.
Installation
1. W ith sealer on exhaust pipes, install pipes into
converter.
2. On CIO m odel, loosely connect support atta c h ­
ing converter-to-transm ission.
3. Install new " U " bolts and clam ps at fro n t and
rear o f converter.
4. Check all clearance and tighten clam ps and
support.
5. Lower vehicle and rem ove from hoist.
Catalyst Removal
If necessary, the catalyst in the co n v erter can be
replaced on the vehicle with Tool N o. J-25077.
1. Install asp ira to r J-25077-2 (Fig. 6F-4).
N O TE: S ep arate hoses should be attached to the
asp ira to r and the v ib rato r w ith m axim um available
pressure. M inim um o f 60 psi in each hose.
2. C onnect a ir supply line to a sp irato r to create a
vacuum in the converter to hold beads in place w hen fill
plug is rem oved.
3. Rem ove converter fill plug as follows:
a. T h read ed plug - Rem ove w ith 3 /4 " hex
w rench o r Tool J-25077-3.
b. Pressed plug - D rive a sm all chisel between
the converter shell and the fill plug. Use care not to
dam age converter shell (Fig. 6F-5). C ontinue to deform
fill plug until it can be rem oved w ith pliers (Fig. 6F-6).
N O T E : Do not pry fill plug from converter as
dam age to fill plug sealing surfaces could result.