Section 22: HEATING AND AIR CONDITIONING
PA1553
51
o Removal
a) Stop engine and allow engine coolant time
to cool.
b) Close shutoff valves. Refer to "05
COOLING" under heading "Draining
Cooling System" for location of valves.
c) Disconnect the electrical wiring from the
motor.
WARNING
Before proceeding with the following steps,
check that coolant has cooled down.
d) Disconnect water lines from pump at
flange connections. Place a container to
recover the residual coolant in the line.
e) Remove the two clamps holding the pump
motor to its mounting bracket. Remove the
pump with the motor as an assembly.
o Disassembly
a) Separate the housing (1) from the adapter
(7) by first removing the 4 capscrews.
Remove housing carefully to prevent
damaging the O-ring (2).
b) Remove rotor assembly (4), washers (3)
and shaft (5) from the adapter.
Inspection
Components removed from the recirculating
pump and motor assembly should be compared
with new parts to determine the degree of wear.
o Brushes
1. When removing brushes, note the position
of the brush in the tube. Brush life is
shortened if the brushes are not replaced
properly.
2. Examine brushes for the following:
a. Wear
Replace the brushes if less than 25%
of the usable brush is left (less than
0.300 inch [8 mm]).
b. Chipped edges
Chips can be caused by improper
handling or installation. Badly chipped
brushes should be replaced regardless
of their length.
c. Annealed brush spring
This can be detected by noting the
resiliency of the spring. Annealing is
caused by failing to tighten the brush
caps properly, thus not providing a
good low resistance contact between
the terminal and the brush tube.
Replace brushes showing evidence of
annealed springs.
d. Frayed or broken pigtail
An improperly installed brush may have
the pigtail (shunt) pinched under the
terminal or between the coils of the
spring. If the pigtail is badly frayed or
broken, replace the brush.
3. Observe the following factors when
replacing brushes:
a. The face of a new brush is carefully cut
to cause proper seating during the
"wear-in" period.
b. Improper installation can harm both the
brush and the commutator.
c. Replacement brushes should be of the
proper grade.
d. Brush performance will be affected if the
spring and terminal are not properly
placed in the brush tube. The spring
should be free over its entire length and
the terminal should make good contact
with the metal brush tube insert.
o Assembly
a) Install washer (3), shaft (5) and rotor
assembly (4) into adapter (7).
b) Install O-ring (2) into housing (1) and
assemble housing to the adapter.
c) Secure housing to adapter using 4
capscrews (6).
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