10
Parker Hannifin
Cylinder and Accumulator Division Europe
Maintenance Bulletin
'Mill Type' Cylinders
MA3 Series
Servicing Piston Seals
When a cylinder is overhauled, a new set of piston seals is
required. Cylinders should always be reassembled with new
cylinder body O-rings and back-up washers (26 and 47).
O-rings and back-up washers are available as a CB kit, and are
included in the piston seal kits described below.
Removal Figs. 1, 5, 6 & 7
When piston seals show signs of wear, it is likely that the gland
seals will also require replacement. If the gland is to be serviced
while the cylinder is disassembled, the gland assembly should
be loosened, as described on page 5, but left in place to sup-
port the piston rod during disassembly. The cylinder should be
removed for overhaul.
1 Remove the hex socket-headed cap screws (23) which secu-
re the head assembly to the front retaining flange, and slide the
head/gland assembly from the piston rod. The gland may now
be removed from the head and serviced separately, as descri-
bed on pages 5 and 6.
2 Taking care not to bruise the piston rod against the edge of
the cylinder tube, pull the rod/piston assembly from the tube.
Prise the cylinder body O-ring and back-up washer from the
groove in the head and clean the groove thoroughly.
3
If the cap needs to be removed, remove the hex sockethea-
ded cap screws (23) which secure the cap to the rear retaining
flange, and slide the cap from the cylinder body. Prise the
O-ring and washer from the groove in the cap and clean the
groove thoroughly.
Low Friction Piston, Fig. 6
Standard Piston, Fig. 5
Chevron Piston, Fig. 7
46
142
17a
55
143
17b
40
41
14a
134
124
45
123
140b
140a
55
127
125
126
46
127
123
141a
141b
40
14a
134
45
132
46
55
133
131
133
Fig. 1
35
34
36
37
18
17 17a
17b
23
7
40
41
70a
69a
19
15
19
14b
14a
70a
69a
1
45
134
26
23
74
73
47
26
27
47
