Chevrolet 10 Series 1970 Service Manual page 291

4. Inspect actuation housing cylin d er bores fo r sco re s,
scratch es, o r co rrosion .
c o rrod ed spots may be polished out with crocus
cloth. N e v e r use e m e ry
scratch es o r co rrosion a re too deep to be polished
out, spider must be replaced.
5. Inspect plungers fo r scorin g,
rosion. Ligh t scratch es m ay be polished out with
crocus cloth. If scratches o r c o rro s io n are too deep
to be polished out, plunger must be replaced.
6. Inspect plunger seal fo r any cracking or d e te r io r a ­
tion. Any d eterio ra tion
should be replaced.
Assembly (Figs. 89 and 9 0 )
1. Install r o lle r s in retaining cage.
2. P la c e w asher in position on retaining cage.
3. In stall wedge in retaining cage.
4. In stall wedge seal.
5. P osition spring on wedge against washer and co m ­
p re s s enough to in sta ll return spring washer and cot­
te r pin.
Installation (Fig. 89 )
1. In stall new sea ls on anchor plungers as shown in
F igu re 91.
2. Install plungers and seals in housing as shown in
F igu re 92.
NOTE: Installation tool shown in F igu re 92 can
The a ir brake system
drau lic brake components with a ir brake parts fo r p ro ­
ducing and u tilizin g g re a te r braking fo rc e s .
co m p re s s o r in the a ll a ir brake system builds up and
m aintains the a ir p ressu re req u ired to operate a ll of the
a ir pow ered d evices.
A p ressu re protection va lv e is in stalled between the
p rim a ry a ir brake system and the a u xilia ry a ir operated
a c c e s s o rie s . A minimum a ir p re s s u re of approxim ately
80 p si is req u ired to lift the v a lv e diaphragm off its seat
and p e rm it a ir to pass to the a c c e s s o rie s . Should the a ir
p ress u re drop below 80 psi, the diaphragm closes off a ll
COMPRESSOR
The T u -F lo 400 and 500 c om p ressors a re single stage
recip ro ca tin g piston type c o m p resso rs. Both the 400 and
500 c o m p resso rs have two cylin d ers.
3 5 ,0 0 0 Miles:
R em ove co m p ressor d ischarge v a lv e cap nuts and check
fo r p resen ce o f e x c e s s iv e carbon deposits. A lso, check
the d isch arge line fo r carbon.
found in eith er check, the cylin d er head or discharge line
should be cleaned o r replaced.
Light scratch es o r sligh tly
cloth o r sandpaper.
scratch es, or c o r ­
is unacceptable and seal
STANDARD AIR BRAKES
GENERAL DESCRIPTION
com p letely rep laces a ll hy­
The a ir
MAINTENANCE AND ADJUSTMENT
If e x c e s s iv e carbon is
be made lo c a lly according to dimensions shown
in Figu re 93.
3. In sert plunger guide with new washer inside slots in
If
anchor plungers.
4. In stall automatic adjuster components as detailed in
applicable procedu re.
5. Install wedge assem bly in actuation housing (R e fe r to
F igu re 94). Be sure r o lle r s are seated c o rre c tly in
retain er cage and make good contact with plungers.
NOTE: Spring reta in er washer has " e a r s " on
each side to be used as guides to assure c o rre c t
installation (See F igu re 90). Housing has ' 's lo ts "
to match " e a r s " on washer (See F igu re 95).
6. In stall brake shoes as previou sly d escrib ed under
" Brake Shoe Installation" in this section.
7. In stall brake cham bers as described previou sly.
8. Connect a ll a ir lines into both chambers.
9. Build up a ir p ressu re in system and push parking
brake knob in to admit a ir into outer cham bers (with
" F a il-S a fe " only).
10. With a ir in outer cham bers, turn re le a s e bolt at each
chamber (if " F a il-S a fe " ) counterclockw ise as fa r as
it w ill go (approxim ately 18 turns). B rakes a re now
in operating condition, eith er fo r s e r v ic e brakes o r
parking.
11. A fte r brakes a re in operating condition, adjust brakes
and repeat operating and leakage tests as p reviou sly
described.
a ir to the a c c e s s o rie s and a ll rem aining a ir p ressu re is
r e s e r v e d fo r the brake system .
N orm a l operation
p erio d ic tests, inspection and adjustment to assure safe,
efficien t operation.
Since the veh icles co vered by this manual w ill be used
in a wide v a rie ty of operations it is d ifficu lt to fix m ain­
tenance in tervals (tim e o r m ilage) which w ill sa tisfa cto ­
r ily suit a ll conditions.
T h e re fo re , such in terva ls stated in these maintenance
p rocedu res must be rela ted to the type of usage to which
the p a rticu lar veh icle is used.
1 0 0 ,0 0 0 Miles:
Depending upon operating conditions and exp erien ce,
disassem ble com p ressor,
thoroughly. R epair
parts.
IMPORTANT:
the engine cooling system to prevent damage
fro m fre e z in g , w ater cooled com p ressors must
be drained as both cylin d er block and cylin der
head a re w ater cooled. Use drain cock o r r e ­
m ove head and/or block pipe plugs.
o f braking system s n ecessitates
clean and inspect a ll parts
o r rep lace a ll worn or damaged
Should it be n ecessary to drain
CHEVROLET TRUCK SERVICE MANUAL
BRAKES 5-53