Chevrolet 10 Series 1970 Service Manual page 293

SPRING
INLET
PORT
CLAMP RING
NUTS A N D
BOLTS
CLAMP
R IN G
F ig . 9 8 —A ir Brake C ham ber (C la m p Ring Type)
GOVERNOR
Every Six M onths or 1 5 ,0 0 0 Miles:
R em ove both go vern or a ir filt e r s and wash thoroughly
in cleaning solvent that is known to have no detrim ental
e ffe c t on m etal, nylon, o r rubber m a terial.
BRAKE VALVE
Every Year or 5 0 ,0 0 0 Miles:
D isassem ble brake v a lv e and clean a ll parts. Install
new in let va lv e s and piston seal.
RELAY VALVE
If the re la y v a lv e does not function as described under
S erv ic e O peration s— R elay V alve (but in any event once
each y e a r) d isassem b le the va lve and clean a ll rubber
p arts and parts subject to w ear should be replaced if
worn o r damaged.
QUICK RELEASE VALVE
Every Y e ar or 5 0 ,0 0 0 Miles:
D isassem b le va lve, clean a ll parts and rep la ce the
diaphragm.
BRAKE CHAMBERS
Every M onth or 2 ,0 0 0 Miles:
Check tra v e l of brake cham ber push rods and adjust
brakes i f n ecessary. Push rod tr a v e l should be kept at
the minimum without brakes dragging.
E x c e s s iv e tra v e l shortens the s e r v ic e
cham ber diaphragm s and also resu lts in slow braking
response.
Every Year or 5 0 ,0 0 0 Miles:
D isassem b le brake cham bers and clean a ll parts. In­
s ta ll new diaphragms. When rep lacin g re le a s e springs
be sure to use the c o r r e c t spring, otherw ise uneven
braking w ill result.
N O N PRESSURE
PLATE
► M O U N TIN G BOLTS
YO KE
5 8 1
I
...
life of brake
SLACK ADJUSTERS
The slack adjusters are fu lly packed with grea se when
assem bled and need no p erio d ic lubrication.
If the slack adjuster is disassem bled fo r any reason it
must be repacked with g rea se in the follow in g way:
1. R em ove one plug fro m the slack adjuster side plate.
2. Using a p ressu re g rea se gun, in ject grease into the
hole in side co v e r w hile turning the w orm shaft ap­
p roxim ately 50 revolutions in one direction.
3. Install side plate plug secu rely.
4. Rotate worm shaft about 3 revolutions in the opposite
direction.
5. R e fe r to Section 0 - Lubrication fo r additional in­
form ation.
RESERVOIRS
D rain a ir r e s e r v o ir s regu la rly , as required.
conditions govern frequency;
am ple, once a month may be sufficient, w hile in humid
areas it may be n ecessary to drain r e s e r v o ir s daily.
S atisfactory draining is accom plished only by leavin g
the drain cock open after the a ir has escaped and until
a ll drainage stops.
Many an efficien t r e s e r v o ir arrangem ent has fa ile d in
its norm al function through haphazard maintenance.
DRAIN COCKS
A ll drain cocks should be p e rio d ic a lly checked fo r
leakage, both fo r leakage past the key and leakage through
the body around the key. Leakage of m ore than a one inch
soap bubble in one second is not p erm issib le.
SAFETY VALVE
Every Y ear or 5 0 ,0 0 0 Miles:
The safety va lve should be rem oved, disassem bled and
thoroughly cleaned. Adjust to 150 psi b lo w -o ff p ressu re
a fter reassem bly.
SINGLE CHECK VALVE
Every Y ear or 5 0 ,0 0 0 Miles:
The check va lve should be dismantled and thoroughly
cleaned.
LOW PRESSURE INDICATOR
Every M onth or 1 0 ,0 0 0 Miles:
Check the e le c tr ic a l connections and the a ir pressu re
at which the contacts close.
If above o r below this range, replace switch.
AIR GAUGE
Check the accu racy of the a ir gauge sem i-annually.
The sim plest way to do this is to com pare it with another
gauge known to be accurate.
Dash gauges may lo se th eir accuracy a fter long p eriods
of s e r v ic e and may req u ire replacing. Continued use of
dash gauges showing e r r o r of m ore than 5 psi high o r
low is not recom m ended.
BRAKES 5-55
L o ca l
in dry clim a tes, fo r ex ­
This should be 58 to 65 psi.
Many state m otor veh icle
CHEVROLET TRUCK SERVICE MANUAL