Hydraulic Lines - Chevrolet 40 SERIES 1971 Service Manual

Sec. 5A - 18
HYDRAULIC BRAKES
1 Connecting Rod
2 Seal
3 Wheel Cylinder Body
4 Piston
Figure 21 -T w in -A ctio n W heel Cylinder
TY PES " F R -3 " AND "F R -3 A " (Fig. 18)
D isa ssem b ly
P u ll boots off ends of c y lin d e rs and rem o ve
pu sh ro d s fro m b o o ts. P u sh p isto n s, cup s, and
sp rin g out of c y lin d e r. R em ove b le e d e r valve fro m
u p p e r c y lin d e r.
In sp e c tio n and R e p a ir
1. R e p a ir k its a r e av ailab le w hich contain the
p a r ts to be re p la c e d w hen o verhauling w heel c y l­
in d e rs .
2. In sp e ct cy lin d er b o re fo r s c o r e s , s c ra tc h e s ,
o r c o rro s io n . Light s c r a tc h e s o r slig h tly c o rro d e d
sp o ts m ay be p o lish ed out w ith c ro c u s cloth. N ever
u se e m e ry cloth o r sa n d p a p e r. If s c ra tc h e s o r c o r ­
ro sio n a r e too deep to be p o lished out, re p la c e
c y lin d e r.
3. C heck fit of new p isto n s in cy lin d e r b o re ,
usin g a fe e le r gauge a s shown in fig u re 19. C le a r ­
an ce should be w ithin 0.001" to 0.005" on " F R -3 "
ty p e. R eplace c y lin d e r if c le a ra n c e ex ceed s the
m axim um .
A ssem b ly
B efo re a ssem b lin g w heel cy lin d er, clean each
p a r t in b ra k e fluid o r alco h o l.
CAUTION: DO NOT use kerosene,
or gasoline for cleaning wheel cylinder
parts. Dip each internal part in hydraulic
brake fluid before assembling.
H yd rau lic b ra k e s y s te m u n its a r e in te rc o n ­
n e c te d by flex ib le hose and sp e c ia l m etal tubing.
F le x ib le hose is u sed betw een m a s te r c y lin d e r (on
cab) and fra m e connection, betw een fra m e and
fro n t w heel c y lin d e rs, and betw een fra m e and r e a r
5 Cup
6 Connector Insert
7 Spring Assembly
T-2699

HYDRAULIC LINES

1. In sta ll p isto n s, p isto n cups, and sp rin g ,
w ith cup lip s tow ard in sid e of cy lin d e r.
2. A ssem b le pu sh ro d s and b oots, then in sta ll
on cy lin d e r. Seat boots evenly in c y lin d e r g ro o v es.
Align pu sh ro d slo ts
3. In sta ll b le e d e r valve in u p per c y lin d e r.
TWIN-ACTION (Fig. 21)
D isassem b ly
P u ll boots off ends of c y lin d e r and rem ove
p u sh ro d s fro m boo ts. P u sh p isto n s, cups, and
sp rin g out of c y lin d e r. R em ove cups fro m p isto n s.
R em ove b le e d e r valve fro m u p p er c y lin d e r.
In sp ectio n and R ep a ir
1. R e p a ir k its a r e a v a ila b le w hich contain the
p a r ts to be re p la c e d when overhauling w heel c y l­
in d e rs . R e fe r to P a r ts Book fo r re p a ir kit p a rt
n u m b e rs .
2. In sp e ct cy lin d er b o re fo r s c o r e s , s c ra tc h e s ,
o r c o rro sio n . L ight s c r a tc h e s o r slightly c o rro d e d
sp o ts may be p o lish ed out w ith c ro c u s cloth. N ever
u se e m e ry cloth o r san d p a p er. If s c ra tc h e s o r c o r ­
ro sio n a r e too deep to be p o lish ed out, re p la c e
c y lin d e r.
3. C heck fit of new p isto n s in cy lin d er b o re ,
using a f e e le r gauge. C le a ra n c e should be w ithin
0.002" to 0.004". R eplace cy lin d e r if c le a ra n c e
exceed s 0.004". R e fe r to fig u re 19.
A ssem bly
B efore a sse m b lin g w heel cy lin d er clean each
p a r t in b ra k e fluid o r alcohol.
CAUTION: DO NOT use kerosene,
or gasoline for cleaning wheel cylinder
parts. Dip each internal part in hydraulic
brake fluid before assembling.
1. In sta ll new cup on each pisto n so open end
of cup w ill be tow ard fla t end of p isto n .
2. A sse m b le boots on pu sh ro d s, being s u re
b ead on boot engages groove in pu sh ro d. In sta ll
boots and push ro d s on c y lin d e rs, engaging bead on
o u te r edges of cy lin d e r housing.
ax le b ra k e lin e . When the hy d rau lic lin e s have
been disco n n ected fo r any re a so n , b ra k e sy ste m
m u st be bled, a fte r connecting lin e s, a s d ire c te d
un d e r "B leeding B ra k e s ."
a s shown in fig u re 18.
CHEVROLET 40-60 TRUCK SERVICE MANUAL