PS Magazine - TB 43-PS-435
PS, The Preventative Maintenance Monthly
ISSUE 435
FEBRUARY 1989
PUT YOuR
Fo±t ²
-
³lE peDAL. I´
SHµ¶·¸
dr¹º i/»
INCh¼
T
he pedal should be firm once you
pass the Fee travel.
A sinking brake pedal is the sign of
a leak. If you can't find a leak, and
the ±uid LeveL in the master cylinder
stays up, the master cylinder may be
bad.*
ThEre is air in the lines if the pedal
feEls soft or spongy. AiR gEts traPped
when the ±uid leVel droPs too Low in
thE
MastEr cyLinDer,
or the brakes
wEren't bled properLy the last time thEy
wErE serviced. Bleed all the lines and
then pump the brakEs seVeral ti²es. If
thE pedal st³rts to so´en again, there
is a leak.
*NOTE: HMMWV's and CUCV±s are difeR·
ent. They hAve a hydRo-boos²eR ²ha² le²s
²he pedaL sink iF you appLy haRd pRess³Re
whiLe you´Re s²oppedµ T¶is can be a
¸ooLeR, so check o³² ²he brakes iF ²he
dRIveR repo¹s i².
28
A sPongy peDal usually Means a hose
has gotten wEak and is rEaDy to burst.
µraKE hose inspection is rEquirED at
each
sEMiannual
service,
but don't
wait
if
you
have
a
spongy
peDal¶
·yeball all hoses, pronto!
¸eplace any hose with a bulgE. ¹ook
close at the hoses that run closE to the
Fame. Check ºr wear and pinching.
»f a hosE is wo¼ or cracked thru the
outer coVer down to the fiRst ply of
½abric, or if it's crimped, replace the
hose. GEt the whole scoop on manda-
tory brake hosE inspEction in TB
9½
¾300¿405À14Á
Painless Bleeding
¾leeding thE lines is a snaP when
you haVE thE right tool .
.. that's ¿llEr/
bleeder, NSN
Â910À00À¾73À365ÃÄ
»t's
in thE No.
1
and No.
¾
CoM²on shop
sEt anD thE insÀructions on how to use
it are in thE truck's
À¾0
TÁ.
fÅB 8Æ
»f you don't have a fÂller/bleeder, it
takes two to bLeed the hydrauLic brake
lines. Here's Ãow it goes:
ÄÅÆ ¸ound up a
1¾
inch long piece of
clEar plastic tubingÇNSN
47¾0À00À
96ÂÇ1433
will doÇand a clear glass
or plastÈc container to catch the Éluid.
Êut about an inch of brake fluid in the
jar.
ÄÅÆ Ëit the tubing over the bLeeder
ValVE on the wheel farthest Fom the
master cyLinder. Êut the loose end of
the tubing down inside the jar into the
Éluid. Always start with the Longest line
whEn you bleed the system. That's the
one with the most aiR trapped inside.
That way you get most of the air out
of the system right oÌ the bat.
ÄÅÆ Áake sure the master cylinder is
Íull of Fesh, cLean ±uid and the cap is
on beºre you bleed each line.
ÎÏÐ Have your buddy pump the brake
pedal at Least three times and then hold
the pedaL down until you say Whoa!
That wiLL keep thE brake Éluid coming
while you bleed.
Have your buddy hold
down ºhe brake pedaL
ÄÅÆ Open the bleeder valve. Watch the
Éluid as it flows thru thE tube. When
you no longer see air bubbles, or when
the Élow stops, tighten the valve and
holler Whoa!
WÈÉn ÊË aÌÍ bÎÏÐÑËs
StO.lGH±£N
VÒÓvÔ
ÕÖ×
WHOA!
ØÙ
ÄÅÆ If the ±uid stopped ±owing beºre
aLl the bubbles Ñere out, have your
buddy pump up the pressure and bLeed
again until you see a steady ±ow of
±uid.
ÄÅÆ Áove to the next Longest Line and
bLeed that wheeL cyLinder. Work your
way down to the shortest Line.
ÄÅÆ Get rid of the oLd ±uid according
to your SOÊ.
ÚÛB 8Æ
2Æ
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