PHQ250JHMAVL Jackleg MK 1 Parts and Repair Manual PDF

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17. Remove the operating handle adapter nut (12812UF) with the limit
plate (AVH664). Check the limit stop dowel pin (AVH662) that
protrudes from the control body for wear. Always replace the rubber
bumper (D2105) in the limit plate regardless of appearance or wear. .
18. Remove the operating handle assembly with the control handle still
intact. The anti-vibration backhead operating handle has a straight shaft
and it should slip out easily. If it is tight rethread the nut and tap gently
on the nut with a hammer.
19. Replace all four O-rings (AVH666) on the operating handle shaft
regardless of the condition of the O-rings.
20. Remove the grub screw (AVH661) and the anti-vibration spring
(AVH665). Compare the tension of the anti-vibration spring with that of
a new AV spring and replace the AV spring it is not exactly the same.
Check the grub screw to be sure it is ok for re-use.
21. If the limit stop dowel pin (AVH662) is
worn remove it with a punch inserted in the
hole behind the pin. Replace with a new pin.
Water Control Valve and Water Tube
22. Unscrew the water control valve assembly (A1506PC1) from the
backhead using an expandable wrench or a large open end wrench.
This valve automatically adjusts water flow through the water tube to
flush drill cuttings from the hole. Air pressure from a port in the
backhead competes with a spring loaded valve to regulate the flow of
water.
23. Always remove the water control valve and the water tube with the
water tube seal (D1675) and spacer (D1674) still in place from the
bore of the backhead. Push the water tube from the front end of the
machine if necessary using end of the wooden handle of a hammer...
24. Remove O-ring (164231) within the recess inside the backhead
bore. This O-ring is always replaced regardless of condition
Version 200711