Wiper Takes Abnormally Low Current; Wiper Takes Abnormally High Current; Removing The Motor, Gearbox, And Wheelboxes; Wiper Arm Fixing Details - MG MGB Workshop Manual

THE
ELECTRICAL SYSTEM
_
N
WIPER TAKES ABNORMALLY LOW CURRENT
Check that the battery is fully charged. The performance of
the motor is dependent on the condition of the battery.
Remove the commutator end bracket
and examine the
brush
gear,
ensuring
that it bears ■rmly
on
the
commutator.
The tension
spring must be renewed if the
brushes do not bear firmly on the commutator. Brush levers
must move freely on the pivots. If these levers are stiff they
should be freed by working
them backwards and forwards
by hand.
Examine
the commutator
and, if necessary, clean with a
fuel-moistened cloth. A suspected
armature
should be
checked by substitution.
WIPER TAKES ABNORMALLY HIGH CURRENT
If an abnormally
high current
is shown on the ammeter,
this may be due to excessive load on the driving shaft. The
stall current of the motor when cold is 14 amps. and when
hot is .8 amps.
If there is no obvious reason for this, such as a sticking
wiper blade, a check should be made at the gearbox.
Remove the gearbox cover and examine the gear assembly,
checking that a blow on the gearbox end bracket has not
reduced the armature
end-■oat. The armature
end-■oat
adjusting screw must be set to give an armature end-play of
.008 to .012 (.20 to .30 mm.).
Sluggish operation with excessive current consumption
may
be caused through frictional
losses in badly positioned
or
defective connecting
tubes. The connecting
tubes can be
checked, using a cable gauge. (Details of this gauge can be
obtained from any Lucas Agent.) The gauge cable is similar
in appearance to the driving rack but is .010 in. (.25 mm.)
larger in diameter
and is less ■exible. The gauge will not
easily pass through
connecting
tubes having less than the
minimum
permissible curvature.
SOGZBW
Fig. N.12
Wiper arm ■xing details
1. Retaining clip.
2. Splined drive.
MGB. Issue5.
25729
3. Locking screw.
4. Locking wedge.
A1277AW
Fig. N. 13
Windshield wiper drive components
1. Cross-head
5. Final gear.
2. Cable rack.
6. Park switch.
3. Outer casing.
7. Connecting rod.
4. Armature.
To check the tubing remove the motor
and inner rack.
Insert the gauge into the connecting
tube as far as the first
wheelbox and
then withdraw
it.
Remove the tubing
connecting
the wheelboxes. Insert and withdraw the gauge.
If the gauge moves freely the tubing is correctly
installed. If
the gauge does not move freely the tubing must be checked
for sharp bends and obstructions. Check the wheelboxes for
alignment and then reassemble.
Removing the motor, gearbox, and wheelboxes
The motor and gearbox is located beneath the passenger's
side of the fascia panel and is mounted on a bracket secured
to the bulkhead panel by three screws.
The cable rack connected to the cross-head in the gearbox
passes through outer casings which connect the gearbox to
the ■rst wheelbox and the ■rst wheelbox to the second
wheelbox.
Disconnect
the wiper arms, the electrical connections from
the motor, and the outer cable from the gearbox housing.
Remove the three screws securing the bracket to the
bulkhead panel and withdraw
the motor, bracket, and cable
rack from beneath the fascia panel.
Slacken the cover screws in each wheelbox and remove the
cable rack outer casings.
Remove the nut, front bush, and washer from the front of
each wheelbox
and remove the wheelbox together with the
rear bush and spindle tube from beneath the fascia panel.
Replacement
is a reversal of the removal sequence, but care
must be taken to ensure that the wheelboxes are correctly
lined up and that the cable rack engages the gear and
spindle assemblies.
N.15