TRUCK SERVICE MANUAL
BRAKES-AIR
ASSEMBLY, ADJUST AND TEST
Before placing the adjusting screw and stem
assembly in the governor body, check to be sure the
Prior to assembly, lubricate the lower body bore,
exhaust stem and its spring are in place in the piston.
the top of the piston, the piston grooves, piston
Install the adjusting screw and spring assembly
grommets, a piston setting spring guide and adjust screw
retaining ring.
using Item 1 in LUBRICANT SPECIFICATIONS.
At this point make the adjustment as outlined
Install the exhaust stem grommet in its groove in
under SERVICE CHECKS.
the stem bore of the piston.
After the adjustment is made, the top cover should
Drop the inlet and exhaust valve into place at the
be screwed on tightly until it seals the body against the
bottom of the piston.
entrance of any foreign matter.
Install the inlet valve spring with its narrow end
If necessary, install new filters in the reservoir and
against the valve. Press the spring down until the large
unloader ports.
These cup shaped filters can be
coiled end snaps into the groove inside the piston.
installed with head of a pencil.
Position the exhaust stem spring over the exhaust
Perform operating and leakage tests as outlined in
stem. Then carefully press the stem into the stem bore
SERVICE CHECKS section when checking rebuilt
of the piston.
governor.
Install the piston in the body.
MAINTENANCE
Install one lower spring seat, spring guide, the
15,000 Miles
other lower spring seat, pressure setting spring and the
Clean or replace governor filters. If cleaning use a
hex-shaped upper spring seat on the adjusting screw, in
cleaning solvent which is known to have no detrimental
that order. Screw the upper spring seat down until the
effect on metal or rubber material.
dimension from the top of the seat to the bottom of the
stem head is approximately 17/8".
100,000 Miles
Install the lock nut.
Disassemble the governor and clean and inspect
all parts.
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