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GM COACH MAINTENANCE MANUAL
Sec. 4
Page 73
or other damage. If damaged in any way, or if
it
has become loose at the soldered joint at the
governor body, the body and tube assembly must
be replaced.
3. Inspect seat on upper valve and upper valve
guide for wear or damage. Also check fit of up-
per valve stem in upper valve guide.
If the seat
on the upper valve shows a decided groove from
wear (fig. 28), or
if
the upper valve stem is not
a neat sliding fit in the upper valve guide, the
upper valve and valve guide must be replaced as
an assembly.
4. Inspect lower valve for wear or damage.
If the valve is grooved excessively (fig. 28),
it
must be replaced.
Check fit of lower valve in
governor body.
It must be a neat sliding fit. If
clearance is excessive, lower valve must be re-
placed.
GOVERNOR REPAIR
1. If the upper valve and seat are not too
badly worn, they may be repaired by carefully
grinding the valve to its seat using valve grind-
ing tool (BWE-211398) and grade 1000 grinding
compound.
To grind valve, temporarily install
upper valve in upper valve guide and screw guide
into body. Valve must be turned back and forth
during the grinding operation using a piece of cord
in manner illustrated in figure 29.
The cord
should be pulled in such a manner as to keep the
upper valve contacting the valve seat on the valve
guide during the grinding operation. Clean valve
UPPER VALVE
'II
GRINDING-'1'
UPPER VALVE
TOOL
'II,.
".;'/GUIDE
CORD
~
/
j
.,
t
,
CORD
AIR COMPRESSOR AND GOVERNOR
---\~1-N __ _...
CORRECT
INCORRECT
SEAT
SEAT
UPPER VALVE SEAT
I
.---LOWER
VALVE
.
'
.
i
I
,
(
.
.
CORRECT
INCORRECT
SEAT
SEAT
LOWER VALVE SEAT
TP
1573
Figure
28-Correct and
Incorrect Governor
Valve
Seats
and seat thoroughly with cleaning fluid after grind-
ing.
2. If lower valve is not worn excessively, it
may be ground to its seat using grinding tool
(BWE-221609) and grade 1000 grinding compound.
To grind valve, insert valve in body, then thread
grinding tool into body. Turn valve back and forth
using cord in manner illustrated in figure 29. A
slight downward pull must be exerted on cord
during grinding operation.
UPPER VALVE
GUIDE
TP
1572
Figure
29-Grinding and
Seating Governor
Valves
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