TROUBLESHOOTING
Page 85
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Worn rocker arm bores or shaft
journals — Inspect rocker arm bores and
shaft journals. Repair as required.
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Worn crankshaft bearings or camshaft
bushings — Replace bearings and
bushings in accordance with MACK
overhaul procedures.
ONE OR MORE CYLINDERS FAIL TO STOP
BRAKING OR ENGINE STALLS
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Control valve inner spring broken —
Replace inner spring.
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One or more control valves stuck in ON
or UP position — Check control valves for
binding. Remove and clean, or replace if
necessary. Inspect lube oil for contaminates.
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Solenoid valve sticking in ON position —
If solenoid valve cap remains down with no
electric current being supplied, replace the
solenoid valve.
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Center solenoid seal ring damaged
(allows oil to enter brake with solenoid
valve closed) — Remove solenoid and
replace all seal rings.
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Solenoid valve exhaust plugged —
Remove any restrictions at exhaust (bottom)
of solenoid valve.
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Clutch switch stuck in ON position or out
of adjustment — Check for proper
operation. Readjust or replace as needed.
ENGINE MISSES OR LOSES POWER
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Slave piston adjustment too tight —
Readjust slave piston clearance in
accordance with the Table on page 80.
SUDDEN DROP IN ENGINE LUBE OIL
PRESSURE
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Upper solenoid valve seal missing or
damaged — Remove solenoid and replace
upper seal ring.
5_106_00.bk Page 85 Friday, August 4, 2000 11:17 AM
BDC for engine manuals and specs