GMC 1976 ZEO 6083 Maintenance Manual page 252

Figure 45-Removing Air Valve Push Rod Assembly
viced using a complete assembly, since the floating
control valve cannot be removed over the eye end of
the push rod .
CLEANING AND INSPECTION
CAUTION :
If there is any suspicion of con-
tamination or any evidence of corrosion,
completely flush the hydraulic brake sys-
tem. Failure to clean hydraulic brake sys-
tem can result in early repetition of trouble.
Do not use gasoline, kerosene, anti-freeze
alcohol or any other cleaner with even a
trace of mineral oil.
After disassembly, immerse all metal parts in
metal cleaner. Plastic parts,
as
well as the rubber
power diaphragms, should be cleaned in Declene or
equivalent . Care should be taken to avoid chipping
or damaging plastic parts in handling . After parts
have been thoroughly cleaned, those parts which
come in contact with hydraulic brake fluid (that is,
all master cylinder parts and the power section push
rod) should be thoroughly washed in Declene or
equivalent before assembly . Use air to blow out dirt
and cleaning solvent from recesses and internal pas-
sages. DISCARD ALL RUBBER PARTS EX-
CEPT THE POWER DIAPHRAGMS .
ASSEMBLY
NOTE :
During assembly, when a lubricant is
specified, use either the lubricant furnished with
the repair kit or Seal Lubricant No . 1050169 or
equivalent .
1 . Lubricate the "O" ring seal, Figure 37 and
place on the air valve.
Figure 46-Installing Retainer Ring
BRAKES 5- 3 3
2. Wipe a thin film of lubricant on the large and
small O.D . of the floating control valve .
3 . If the floating control valve needs replacement,
replace the complete air valve push rod assembly .
4. Place the air valve end of the air valve push rod
assembly into the tube of the primary power piston .
Manually press the air valve push rod assembly so
that the floating control valve bottoms on the tube
section of the primary power piston .
5 . Place lip of retainer on the O.D . of Tool J-
23175. (figure 46) Manually press the retainer until
seated in the primary power piston tube . (figure 47)
6. Place the push rod limiter washer over the
push rod and position on the floating control valve .
7. Install filter element over the push rod eye and
press into the primary power piston tube .
8 . Using snap ring pliers, place the snap ring into
the groove in the air valve.
9. Install the rubber reaction bumper on the air
valve .
NOTE:
Tolerances of component parts affecting
output of the tandem power brake are very criti-
cal. To maintain correct power brake output, the