MCi Crusader II 1989 Maintenance Manual page 76

Date
1-1-89
Page __
3 _· 5 _ _ _
MC-9 MAINTENANCE MANUAL
::ORROSION PREVENTION
Preventive maintenance is a key factor in avoiding corrosion
and must be considered as part of the regular service intervals.
The entire underside of the coach is sprayed with a heavy
application of asphalt base undercoating. Also, all fasteners are
corrosion resistant
The type of operating environment a coach is exposed to
determines the amount of dirt and corrosion that it will accumu-
late over any given operating period. Corrosion is one of the
most costly factors of part failure and abbreviated part life. It is,
however, an item that c;an be controlled when it is conscien-
tiously looked for and the proper steps taken within a reason-
able amount of time.
Certain areas of the coach are more vulnerable to corrosion
than others and it is these areas that should be addressed. For
example, the rear baggage compartment bulkhead in the rear
wheelhousing area should be examined regularly tor corro-
sion. This location contains many key components: relay valve.
suspension air filter. dry air tank, inversion valve, parking brake,
pressure regulator, and numerous other valves and fittings.
Other areas include the front wheelhousing area, spare tire
compartment. front left side service area, and engine compart-
ment.
Road splash will affect undercarriage. sides of coach. fresh
air intakes. condenser coil and engine compartment These
areas must be thoroughly cleaned to remove "dirt packs" from
flanges. channel and ledges. These places accumulate dirt and
salt and hold it in direct contact with steel and aluminum sur-
;aces. Use an understructure high pressure spray as part of a
regular wash. Damaged undercoating or paint should be
promptly repaired before corrosion can start
Frequency of wash periods depends on operating condi-
tions. During periods of exposure to salt daily washing as de-
scribed above is necessary.
If underbody parts show evidence of rust or corrosion. treat
as follows:
1. Clean. Remove dirt, grease and oil. by solvent washing.
2. Remove corrosion as well as all loose deadener coating
by sanding with wire brush or with other means.
CAUTION: Sandblasting can be used for
cleaning bulkheads, brackets and other
structural members. However, If should not
be used for exterior side paneling. Extreme
care should be taken not to sandblast
excesslvely.
After removing all corrosion, correct priming, painting and
undercoating must be applied to prevent further damage.
ROUTINE CLEANING
Wash and rinse water should be free of solids. It is especially
important to assure that recirculating systems are properly
designed, maintained and monitored for efficiency. In all cases
suppliers of recirculating systems should provide assurance
,at their equipment and techniques will function satisfatorily
with Lucite® windows. -
Two types of detergent are necessary for optimum washing
efficiency. A solvent-based dissolving type of detergent should
be used with the prewash spray. A highly lubricating type of
detergent should be used with brushes.
In each case, the detergent manufacturer should be con-
sulted regarding recommendations on concentration. Addi-
tionally, the water /detergent mixture should be 90°F to 110°F
to improve cleaning efficiency. .
Most high quality detergents contain sequestering agents
and are effective in water of up to eight grains hardness. This
does, of course. depend heavily on the particular detergent and
its concentration. If the detergent does not contain sequester-
ing agents, water should be softened to four grains hardness or
less for effective detergent action. In all cases, the detergent
supplier should be contacted for recommendations on deter-
gent and soft water requirements.
A good, high pressure water spray prewash is vital to remove
as much grit and grime as possible before brushing. Detergent
may or may not be employed with the prewash. If detergent is
used, follow the recommendations above, allowing enough
time for the detergent to soften the grime before other washing
steps. If detergent is not used in this step, please follow the
directions under "Detergent Prewash" below. For alternative
washer arrangements, please see figure 3-3.
1
I
a--tlll't.
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(7
.S-12.2M)
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l
Bnab F&.
,.._w.,,,
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Lullril:atin9
s.,,.y
2
t&-r
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a--tlll't. I I I
(7 .S-12.2M)
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Final
....
. . . Dalorlllnt
.......
..........
s-r
3
I
25-401't.
I I
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(7.~12.2M)
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. J ...
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Figure 3-3. Washing Equipment Schematic.
DETERGENTPREWASH
In cases where the initial prewash spray does not contain
detergent. we recommend that a small additional spray arm be
installed to cover the window area only. This arm should be
located far enough from the prewash spray so that its
effect
is
not diluted by additional water (probably 5-7 feet [1.5-2.1 m]).
Alternatively, this could be located in front of the main prewash
station if sufficient distance can be provided so as to allow the
detergent time to act (25 to 40 feet at 1-2 MPH [7.6-12.2 m at
1.6-3.2 km/h]). Where possible, warm water (90°-110°F [32°-
43
°
CD should be used with detergent