- 11 -
diaphragm. If there is doubt as to whether the charge is correct, the
accumulator should be replaced with a service exchange unit available
from MASTERPAC ENGINEERINGCO.,LTD or authorised agents
8.5 Head Assembly (refer also to section 10.7 PAV20/20.07 Head
Assembly
）
1.It is useful to tie a rag around the breaker cylinder to absorb oil
released when the joint faces between head and cylinder are parted.
2. Remove the acorn nut
（
65
）、
complete with the M12 bonded
washer(67)& grub screw
（
66
）。
3. Remove the two cap screws
（
71
）
securing the head to the cylinder.
。
4.Screw one of the cap head screws removed in operation 3 into the
central hole in the head and use it as a jacking screw to lift up the head
from the cylinder and the oscillator assembly
（
69
）。
5. Lift away the head and remove the jacking screw.
6. Push the starter spool rod
（
70
）
downward to remove the starter
spool assembly. The top gland of the starter spool assembly will
remain in the head. This may be removed by pushing upwards with a
drift of suitable diameter. For more details on the starter spool see
section 10.7.2.
7. Remove oscillator spool assembly
（
7
），
dismantle, clean and check
condition. If scored, badly worn or the spool does not move freely, the
entire assembly will need replacing. See section 10.7.1 for more
details.
8.6 Cylinder Assembly (refer to Section 10.4 PAV20/20.03 Cylinder
Assembly)
1. Remove and discard the
‘
O
’
ring on top of the injector.
2.Prise out the injector using a pair of screwdrivers as levers. Take
great care not to damage the injector. Remove and discard the
remaining
‘
O
’
rings.
3. remove the spiral-retaining ring
（
27
）
using a pair of small
screwdrivers, one to ease the end of the ring out of the groove
and the other to ease it upwards. Continue in this way to ease out
the complete ring.
4. Remove the pinch bolt nuts holding the nose onto the cylinder.
（
26
）。
5. Remove the pinch bolts.
6. Remove cylinder (6)from nose.
（
25
），
If the nose is tight on the
cylinder driving a wedge into the slot may ease this.
7. Gently prise out the seal housing.
（
24
）。
8. Remove the piston
（
21
）
by pushing it upwards.
。
9. Examine surfaces of piston. Cylinder and injector. Components and
their mating parts, which are worn or deeply scored, must be
renewed. Slight scratches may be polished out with metal polish.
