39
SYMPTOM
Air motor and/or clamp and feed func-
tions do not start when trigger is de-
pressed.
Air motor does not run when trigger is
depressed, but feed and clamp func-
tions work properly.
Air motor "idles" when trigger is released.
Motor runs and the tool clamps workpiece
but does not feed.
Tool lunges during feed or when drills
exit the far side of the workpiece or
variation in feed rate.
REASON
Trigger or pilot valves clogged with for-
eign matter.
Gears damaged or jammed with debris.
Foreign matter in motor inlet.
Motor throttle valve adjusted too far,
stopping air flow to motor.
Broken rotor blades, rotor or gear bear-
ings.
Pilot valve sticky (not fully closed), or bad
"O"-rings on valve sleeve.
Leaking "O"-ring on air motor rear bear-
ing support.
Feed control needle valve "closed".
Debris in hydraulic system.
Air in hydraulic system.
Damaged or worn "O"-ring on collet pis-
ton.
SOLUTION
Disconnect air line then remove trigger
and pilot valves and inspect for debris.
Inspect "O"-rings and replace if neces-
sary.
With air line disconnected from tool,
remove backhead, clean and inspect
hears for damage and check both
spindles for free rotation.
Remove motor and clean debris from
the motor inlet ports.
Adjust valve until end of valve stem is
flush with the end of housing.
Remove motor and inspect rotor blades
and bearings. Replace if necessary.
Remove and inspect valve for debris
and for free movement of valve spool.
Inspect "O"-rings, lubricate and reas-
semble.
Remove and inspect "O"-rings. Replace
if necessary and reassemble.
Turn feed control needle valve counter-
clockwise until feed commences.
Remove feed control valve needle and
bleed hydraulic system until fluid is clear.
If air in hydraulic system continues to be
a problem, remove the hydraulic reser-
voir piston and check or replace its "O"-
rings. Also check or replace the inner
and outer "O"-rings on the pressure head
located in the main cylinder.
Check or replace "O"-ring.
TROUBLESHOOTING GUIDE FOR 15 NUT PLATE DRILL MOTOR
