TM 5-3805-280-24-1
Problem
Possible reasons
1)
Important vibration of drifter hoses
t
P2 hose : Deflated or punctured HP accumula
ors.
LP P2 hoses : Deflated or punctured LP accu
m,
ulator.
2)
Overheating on drifter front part
Check :
- Pressurization circuit
- Air pressure reducer.
- Oiler.
- Feed pressure if too low.
3)
Coupling sleeve overheating, important
Feed pressure too low.
vibration level or erratic motion.
Increase feed pressure.
If unsuccessful, check :
- Bit wear
- Flushing (insufficient)
- Rubbing of drifter cradle on guide
- Feed motor if internal leak.
4)
Rotation speed irregular or too low.
If rotation back to normal while drilling in
manual mode, check rotation circuit relief valve
setting.
If still irregular while drilling in manual mode,
check the drifter rotation motor for internal leak.
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