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15-4
GROUP 15·
LIGHTING SYSTEM, HORNS AND INSTRUMENTS
-
y·
FIG. 1 -Installation Speedo Cable.
SPEEDOMETER DIAGNOSTIC
PROCEDURES
' '
Speedometer system complaints are
generally the result of a visible or
audible defect in the system.
It
is im-
perative that the specific defect be
determined prior to attempting any
physical repairs to preclude unnec-
essarily disassembling system compo-
nents.
The following suggestions are
intended to aid in quick and accurate
system problem diagnosis.
VISIBLE DEFECTS
Slight Needle Waver or
Severe Needle Fluctuation
(No Noise)
I. Loose cable retainer
.
l. Defective speedometer head.
3. Bent cable core at attaching
nut.
4. Kinked or pinched cable hous-
ing.
5. Excessive grease in speedome-
ter head.
Inoperative
1. Broken cable core.
l. Defective drive and/ or driven
gear.
3. Defective speedometer
head.
AUDIBLE DEFECTS
Clicking or Ticking (With
Needle Waver), Grinding
or Ringing
/
I
\
-----\
~
.
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'
\ '
,,
'
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\
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'
I. Loose cable retainer.
l. Defective drive and/ or driven
gear.
3. Defective speedometer head.
4. No lube on cable.
SPEEDOMETER
REPAIR
PROCEDURES
NOTE: To effect any tests or repairs
on the speedometer head the instru-
ment cluster must be detached from
the instrument panel (see page 15·15)
to gain access.
DEFECfiVE
SPEEDOMETER
HEAD
Before removing a speedometer
head, disconnect the cable at the
head and insert a short section of ca-
ble core in the head. Rotate the sec-
tion of core to check for any drag-
ging or
noise.
The speedometer shaft
should turn freely and
evenly.
DEFEq'IVE CABLE CORE
AND HOUSING
1. To check for a kinked cable
core remove and wipe
dry.
Lay the
core out stra\ght on a flat surface
and roll it back and forth
.
Any kinks
or damage will be seen. Then take
an end in each hand, allowing core
to hang in approximately a 9-inch
loop. Rotate both ends to be sure
core turns
evenly.
2. Routing of the cable housing is
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particularly important where the ca-
ble leaves the speedometer head. The
optimum routing would provide that
the cable and housing take virtually
no change of direction for at least
a length of 8 inches from the
speed-
ometer
head.
3. When installing a new cable
and housing it is necessary that the
new assembly be guided and routed
properly to eliminate any
kinks.
4. Proper lubrication of the cable
core is accomplished by a light
application of a lubricant after the
cable has been wiped clean. A light
film is all that is required.
DEFECTIVE DRIVE AND
DRIVEN GEARS
1. A score nicked or gouged driv-
en gear is usually indicative of a de-
fective drive gear on those vehicles
that have the drive gear integral
with the transmission output shaft.
The output shaft should be
carefully
inspected for imperfections and re-
placed if necessary.
2. A driven gear with two or
three adjoining teeth badly scored is
indicative of improper
assembly
pro-
cedure. The gear should be inserted
in the transmission while simultane-
ously turning the drive shaft. This
will insure initial gear engagement
and prevent gear
damage.
Force
should never be used.
3. Whenever a drive gear is re-
placed, a new driven gear should al-
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