MCi Crusader II 1989 Maintenance Manual page 113

Date
1-1-89
Page _ _
3_-3_a _ _
MC-9 MAl~TENANCE MANUAL
Defective motor valve
Solution: Check the primary and secondary valve rods to
see if they are binding in the chambers. Check for defective
0-rings on the rods.
Clogged air passages in motor
Solution: Disassemble the motor and clear air passages.
Linkage locked up
Solution: Check that transmission shaft has been properly
inserted. Also check drive pin for excess wear and proper
lubrication. Check to see if linkage is hitting against the coach
window side. This may be due to improper size drive bar or pin,
pulling linkage out of proper line of travel.
Motor is getting air, but shaft is not.turning
Solution: Check all drive components for broken valve
pin. gear or rack. Also. examine gear and rack for excessive
wear which may be making improper gear engagement. If a
tapered shaft is used. check to see if it has broken loose from
the gear.
2. MOTOR OPERATES BUT WIPER ARM DOES NOT MOVE
Shaft is operating but arm does not move
Solution: Check.if arm driver is cracked, or has become
disengaged through wear or some other cause.
3. MOTOR OPERATES AT LESS THAN FULL POWER
Air leak in the Control Valve
Solution: Check 0-rings for wear or flat spots.
Air leak in the Wiper Motor
Solution: Examine the large 0-rings on piston rack for
wear or flat spots. Also. examine the cylinder walls of the motor
to see if they are scored to allow air to bypass the 0-rings.
4. MOTOR OPERATES IN AN ERRATIC MANNER
Reverser "T" drilled off center. not drilled deep enough, or
it may hang up on reverser rod
Solution: Disassemble motor and examine reverser "T' to
see if the hole for the valve pin is drilled on center and deep
enough to allow full acceptance of pin. If "T" is hanging up on
rod. lubricate the "T" and examine bore for flash. Examine rod
for sludge deposit which could cause "T" to stick.
0-rings fit too tightly in bore of motor valve
Solution: Disassemble motor valve by removing the end
plates. Examine primary and secondary valve rods to see if any
0-rings show a high spot or complete oversize.
0-rings too tight in main cylinder bore
Solution: Examine large 0-rings on piston assembly for
high spots or complete oversize. Also, examine cylinder wall
bore to see if there is dirt or sludge on which piston may be
sticking.
Exhaust ports plugged
Solution: Examine ports to s~e if plugged or blocked.
Clean and clear them to allow free escape of air from motor.
Unused parking end plate plugged
Solution: If motor valve has parking end plate on both
ends, check
to
see that the unused park end plate is not
plugged.
5.
SLAMMING
ACTION BY ARM ON ONE SIDE OF SWEEP
Loss of pressure at one end of cylinder. causing no back
pressure on returning swing of motor
Solution: Replacement of main 0-ring. Clean port to allow
air passage to maintain proper air pressure in cylinder. Exam-
ine 0-rings on primary and secondary rOds and replace if worn.
6. MOTOR SWEEPS "SHORT" IN ONE DIRECTION
Reverser
•-r·
drilled off center
Solution: Disassemble motor and examine' reverser "T" on
reverser rod. Hole for valve pin must be dri_lled on center.
. Defective primary valve rod
Solution: Remove primary valve rod from motor valve and
see if the rod is sticking due to sludge or residue in bore
cylinder. Clean bore and lubricate. Check and replace improp-
erly sized or worn 0-rings.
Defective cylinder or cylinder 0-ring
Solution: Disassemble motor and examine large 0-rings
on piston rack for wear. Examine cylinder wall for sludge which
would cause piston to.stick or stop short of full travel. Check
cylinder wall for defects or cracks which could stop the piston
travel.
7. MOTOR OVERSWEEPS (OFF THE GLASS)
'il\tlrn transmission gear rack in motor
Solution: Disassemble motor and check gear and rack for
wear. Replace worn parts.
Piston stops worn or broken
Solution: Examine piston rack to see if piston stops on the
reverse rod are still proper length. Replace as necessary.
Worn arm pivot points, causing arm to slip on shaft when
shaft stops
Solution: Examine the shaft first to be sure it is not slipping
in the gear. If not, examine the point when the shaft attaches to
tne arm. See if arm driver is worn or broken. If so. replace arm or
arm driver.