Chevrolet 10 Series 1970, Service Manual

Page: 281 / 671

BRAKES 5-43
STOP PLATE
RAM GUIDE
RAM
LATCH PLATE
DIE BLOCK
TUBEX
\
PLATE
RAM GUIDE
RAM
LATCH PLATE
DIE
TUBE\
F ig . 7 3 —F la rin g O p e ra tio n P o s itio n in g Tubing
F ig . 7 4 —F la rin g O p e ra tio n —First F la re
6
.
7.
two points in appropriate d irection , rep lace reta in er
sprin g and re -in s p e c t as outlined in this paragraph.
P la c e ste e l tube connector in hose fittin g and tighten
secu rely.
B leed a ll brakes as outlined in this section.
Hydraulic Brake Tubing (Figs. 71 thru 7 5 )
H ydrau lic brake tubing used on a ll trucks is a double
la y e r fle x ib le steel, copper coated and tin plated tubing
which re s is ts co rro s io n and also stands up under the high
p re s s u re s which a re developed when applying the brakes.
In making up hydraulic brake pipes, it is im portant that
the ends o f the tubing be fla re d p ro p e rly fo r the c o m p re s ­
sion couplings. U nless the tubing is p ro p e rly fla red , the
c o u p l i n g s w ill leak and the b r a k e s w ill becom e
in e ffe c tiv e .
Th is safety ste e l tubing must be double-lap fla re d at
the ends in o rd e r to produce a strong lea k -p ro o f joint.
The T o o l J-2185 must be equipped with the p rop er s ize
die block and upset fla r e punch fo r each s iz e tubing to
fo rm the double-lap fla re .
The p ro p e r s iz e die blocks and upset fla r e punches are
as fo llo w s :
Tubing Size Die B lock
3/16”
1/4"
5/16"
J-2185-27
J-2185-28
J-2185-29
Upset
F la r e Punch
J-2185-3
J-2185-37
J-2185-4
Finish
F la re Punch
J-2185-26
J-2185-26
J-2185-26
F igu re 71 shows two p ieces o f tubing— one with a
s in g le-la p fla re
“ A ”
and the other with a double-lap
fla r e “ B ” . It w ill be noted that the sin g le-la p fla r e splits
the tubing while the double-lap fla r e shown in “ B ” is a
heavy, w e ll-fo r m e d joint.
The follow in g procedu re should be follow ed in making
up hydraulic brake pipes:
1. Cut the tubing to the d esired length, using Tool
J-8000. Square o ff ends o f tube and ream sharp
edges with re a m e r tool p rovid ed on the tube cutter.
2. Install com pression couplings on tubing and dip end
F ig . 7 5 —F la rin g O p e r a tio n —First and Second Flare
o f tubing to be fla re d in hydraulic brake fluid. This
lubrication resu lts in b etter form ation o f the fla r e .
3. Select the c o r r e c t s iz e upset fla re punch. One end
o f this punch is hollowed out to gauge the amount o f
tubing n ecessa ry to fo rm a double-lap fla re .
4. Slip the punch into the tool body with the gauge end
toward the die blocks, in stall the ram and tap ligh tly
until the punch m eets the die blocks and they are
fo rced s e c u re ly against the stop plate.
5. Draw latch plate nuts down tight to preven t tube from
slipping. Draw nuts down altern ately beginning with
nut on closed side to prevent distortion o f plate.
6. R em ove punch and ram . R e v e rs e punch and place
back in tool body. In stall ram and tap ligh tly until
face o f punch contacts face o f die blocks to com plete
fir s t fla r e operation.
7. Rem ove ram and punch.
8. Insert finish fla r e and ram in tool body and tap ram
until a good seat is form ed.
9. Blow tubing out with com pressed a ir.
VACUUM POWER BRAKE UNITS
(1 0 - 2 0 - 3 0 SERIES)
GENERAL DESCRIPTION
The M aster Vac (fig s . 76 and 77) is a self-con tain ed
hydraulic and vacuum unit fo r pow er braking, u tilizin g
m anifold vacuum and atm ospheric p ressu re fo r its pow er.
The M a ster-V a c p ow er brake unit p erm its the use o f
a low brake pedal as w e ll as le s s pedal e ffo rt than is
CHEVROLET TRUCK SERVICE MANUAL