MCi Crusader II 1989 Maintenance Manual page 462

Date
1-1-89
Page . __
1_s-_3 _ _ _
MC-9 MAINTENANCE MANUAL
TIRES
MAINTENANCE
The correct maintenance procedure is essential to safe and
economical tire service. Daily, inspect each tire carefully for
cuts or foreign matter such
as
nails, glass, etc. Remove any
foreign matter lodged between tires and dual wheels.
Check tire inflation pressure (figure
15-5) with an accurate.
gauge. Pressure should be checked before starting a run and
should be as recommended by tire manufacturer. Always use
the same guage to check the pressure to eliminate any differ-
ences resulting from gauge error.
-OVER
INFLATED
UNDER
INFLATED
PROPERLY
INFLATED
F1gure 15-5. Tire Inflation.
If pressure loss is greater than normal. remove and inspect
tire to determine cause. Replace any missing valve caps.
-NOTE: Tire prct1sure should be checked
with pressure cold.
The valve core is a spring loaded check valve in the stem
permitting inflation or deflation of the tire. The valve is provided
to seal the air in the tire. When the valve cap is tightened on the
stem. the sealing washer inside the cap is pressed tightly
against the top of the stem, preventing air leakage.
REPLACEMENT
When tires are changed. especially to the new.low profile
t1 res riow available. clearances and revolutions per mile may be
affected. Before making changes to tires with different specifi-
cations. ensure that the replacement tires have adequate clear-
ances and that the revolutions per mile are not seriously
affected. Customers wh.o have already changed to replacement
tires. especially to low profile tires. should check to ensure that
the tires are not rubb•ng and that the revolutions per mile have
not affected the speedometer reading.
INFLATION
Improper inflation is the greatest cause of accelerated tire
wear. Tires should be checked frequently for this condition.
Unless correct air pressure is consistently maintained, tires will
not function as they should; consequently, safe, economical
operation of the coach will be affected.
An under-inflated tire runs sluggishly, heats up quickly
because of greater flexing, and is subjected to more frequent
bruising. Over-inflation does not compensate for over-loading.
It does not add strength to the tire; in fact. it actually weakens the
tire by reducing its ability to absorb road shock, and may cause
a blow-out
In addition to the effect improperly inflated tires may have on
tire life, improperly inflated tires will degrade steering, riding
comfort, and safe driving.
All tires on the same axle should always carry the same air
pressure. A difference in air pressure between rear tires and
front tires may be permissible within certain limitations: how-
ever, there should not be a difference in pressures between the
right and left tires on the same axle. A 5 psi (34.5 kPa) under-
inflation in one front tire not only can cause hard steering, but
can create steering hazards which may cause unsafe opera-
tion. An under-inflated rear tire can seriously affect braking.
Balance tire pressures for ease of steering, comfort in riding,
safety in driving, as well as for minimum fuel consumption and
maximum tire mileage.
NOTE: Before rotating tires, consult the tire
manufacturer. They are the source for direc-
tions relating to specific tires.
ROTATION
Radial tires should be rotated only when necessary. If the
tires are wearing evenly, there is no need to rotat~ If irregular
wear becomes apparent. or if the wear rate on the tires is
perceptively uneven, the tires should
t?e
rotated in such a
manner to alleviate the problem. There is no restriction on
criss-cross rotation.
Bias-ply tires should be interchanged at regular intervals to
obtain maximum life. Change wheels without dismounting tires
so direction of rotation will be reversed. The following system of
interchanging is recommended: Right frontto left rear inside or
right rear outside. Left front to right rear inside or left rear
outside.
If inside dua! tires show more wear than outside dual tires.
place front tires on inside when changing. In this case, outside
dual tires can be interchanged between right and left side of
vehicle.
If outside dual tires show more wear than inside dual tires.
place front tires on outside dual tires when changing. At the
same time, interchange right and left hand inside dual tires.
New tires should be installed on front wheels where they run
coolest Baggage should l:)lways be placed as far to the rear as
possible. This puts the load on the rear axle and reduces front
tire stress.
SAFETY PRECAUTIONS
WARNING: Exercise care when handling
wheels and tires. Careful attention
to
the
following suggestions wlll prevent injury.
Make it a rule to respect the explosive force
contained In an inflated tire.
Refer to figure
15-6.
1,
Prepare for any tire repair operation in a proper way. In
servicing tires be careful not to drop them on the feet. hands or
body, or heavily on the floor. Practice proper methods of lifting.
When carrying tires or wheels avoid oil and objects on the floor.
Keep floor clean and dry.
2. Deflating a tire properly is very important. First reduce
pressure as much as possible by pushing the valve core
plunger. Keep your eyes away from valve. Remove valve core
to
ensure complete deflation. Wear approved safety glasses or
goggles when using compressed air.