Chevrolet 10 Series 1970, Service Manual

Page: 241 / 671

BRAKES 5-3
anchor pins at the shoe heels and adjusting screw s at the
shoe toes which act as anchors in the r e v e r s e d irectio n of
rotation. Each adjusting s crew is threaded into o r out of
its support by means of an adjusting wheel. Adjusting
w heels are a c c e ssib le fo r adjustment through adjusting
slots in the flan ge plate.
F ig . 3 —T w in p le x Rear Brake
1. W h e e l C y lin d e r H eat S h ie ld
2 . W h e e l C y lin d e r
3. Brake Shoe Return S pring
4 . W h e e l C y lin d e r Push Rod
5. Brake Shoe
6. O v e rrid e Spring
7. H old Down Pin
8. O v e rrid e Lever
9. S tarw h eel
10. Brake Shoe A n c h o r
SELF ADJUSTING BRAKES (W A G N E R ) (Fig. 6)
NOTE: A ll 50 s e r ie s Flat Face Cowl m odels
with 7,000 lb. fron t axle and or 17,000 lb. r e a r
axle, a re equipped with W agner hydraulic s e lf-
adjusting brakes, fron t and re a r.
The W agner “ F A ” fron t brake shoes must be p r e ­
adjusted at installation in the sam e manner as manually
adjusted brakes, then autom atically adjusted when the
adjusting le v e r (A ) changes position in rela tion to the
shoe web (B ) as the contact plug (C ) is brought to b ea r on
the adjusting cam (D) causing the shoe to rem ain in its
adjusted position.
The W agner " F R 3 A ” r e a r brake shoes a re adjusted by
link crank adjusters (E ). On a r e v e r s e brake application
the head of the shoe (F ) m oves away fr o m its fo rw a rd
acting anchor (G) which cocks the link (H) crank system .
If lining clearan ce is sufficient, the crank pawl (I) picks
up the next tooth on the starw heel. The adjustment is
com pleted on the next brake re le a s e as the adjuster
sprin g (J) returns the crank pawl causing the starw h eel
to advance one tooth.
eith er toe o r heel, depending upon the d irection of drum
rotation. Both shoes a re always p rim a ry shoes, s e lf-
e n e rg izin g in eith er d irection of drum rotation. Brake
anchor supports, bolted to the axle housing flange in con­
junction with the flange plate, have rem ovable slotted
F ig .
4—
W agn er Type “ F ” Front L e ft Brake
F ig . 5 —W a g n e r Type “ F R -3 ” Rear Brake
W h e e l C y lin d e r H eat S h ie ld
U pper W h e e l C y lin d e r
A n c h o r Pin
Return Spring (S ho rt)
G u id e W asher
G u id e B olt
G u id e B o lt N u t Lock
W ire
8. Brake Shoe and L in in g
Assem bly
9. Return S pring (L ong)
10. A d ju s tin g W h e e l Lock
S pring
11. A d ju s tin g W hee l
12. Lower W hee l C y lin d e r
13. B acking P late
CHEVROLET TRUCK SERVICE MANUAL