GMC 1990 Light Truck Repair Manual page 342

5-6 BRAKES
5. Primary piston assembly (30).
6. Snap ring (31).
• The primary piston must be compressed to
install the snap ring.
7. Diaphragm (23) into the cover (22).
8. Cover (22).
Figure 11— Removing the Reservoir
1. Cover
2. Diaphragm
3. Reservoir
4. Grommet
5. Q uick Take-Up
Valve
6. Spring
7. Spring Retainer
8. Primary Seal
9. Secondary Piston
10. Secondary Seal
9. Tube seats (if removed).
• Seat the tube seats with a spare brake tube
nut (figure 18).
BENDIX MASTER CYLINDER
The Bendix Master Cylinder has identifying information
stamped into the front surface of the body. The first digit
indicates the plant where it was built. The second digit
indicates the year it was built (a 5 means 1985 or a 6
means 1986). The last digits indicate the day it was built
(271 means the 271st day of the production year).
N O T IC E : D o n o t h o n e th e m a s te r c y lin d e r b o re .
W h e n th e b ra k e m a s te r c y lin d e r is o v e rh a u le d ,
it is re c o m m e n d e d th a t th e c y lin d e r b o d y b e
re p la c e d ra th e r th a n "c le a n e d u p " b y h o n in g
th e b o re . T h e m a s te r c y lin d e r h a s a h a rd , h ig h ly
p o lis h e d "b e a rin g iz e d " s u rfa c e , w h ic h is
p ro d u c e d b y d ia m o n d b o rin g fo llo w e d b y b a ll o r
ro lle r b u rn is h in g u n d e r h e a v y p re s s u re . H o n in g
w ill d e s tro y th is s u rfa c e w h ic h w ill c a u s e ra p id
w e a r o f ru b b e r c u p s .
N O T IC E : D o n o t u s e k e ro s e n e , g a s o lin e , o r a n y
o th e r u n a p p ro v e d s o lv e n ts fo r c le a n in g o r
flu s h in g m a s te r c y lin d e r a n d c o m p o n e n ts . T h e
u s e o f th e s e a s s o lv e n ts o r a n y o th e r w ith a
tra c e o f m in e ra l o il w ill d a m a g e ru b b e r p a rts .