9
Parker Hannifin
Cylinder and Accumulator Division Europe
Maintenance Bulletin
'Mill Type' Cylinders
MA3 Series
Installation
Figs. 1, 2 & 3
Inspect the surface of the piston rod for damage which could
cause early seal failure. When fitting the gland over the rod thread,
a slight rotary motion will help prevent damage to the seals.
In addition, shim stock or similar thin, tough material can be
wrapped around the threads to protect the seal lips.
Standard Glands Figs. 1 & 2
1
Ensure that the kit contains seals of the correct group.
Lubricate the gland and seals, and fit the wiperseal (40) into the
first groove, closest to the outside face of the gland.
2
Install the lipseal (41) in the fourth groove, with the lips facing the
pressure (cylinder) side of the gland.
3
Fit a pre-load ring (124) into the fifth groove, followed by a step
seal (123), with its step facing away from the wiperseal as shown
in Fig. 2.
4
Fit the wear rings 140a and 140b to the second, sixth and
seventh grooves, as shown.
Low Friction Glands Figs. 1 & 3
1
Ensure that the kit contains seals of the correct group.
Lubricate the gland and seals, and fit the wiperseal (40) into the
first groove, closest to the outside face of the gland.
2
Fit a pre-load ring (124) into the third groove, followed by a step
seal (123), with its step facing away from the wiperseal as shown
in Fig. 3. Repeat for the second pre-load ring and step seal, in the
fifth groove.
3
Fit the wear rings 141a and 141b to the second, sixth and
seventh grooves, as shown.
Standard and Low Friction Glands Figs. 1, 2 & 3
4
Each gland service kit contains an O-ring (45) which acts as a
seal and torque prevailing lock between the gland and head. This
is a static seal, and may be left in place unless faulty. If damaged,
the old O-ring and back-up washer (134) – if fitted – should be
removed from the gland, and the groove thoroughly cleaned.
Lubricate the replacement parts, and fit the back-up washer,
followed by the O-ring.
5
Lubricate the gland, seals and wear rings, and slide the gland
onto the piston rod.
6
50mm – 100mm bore cylinders: tighten the gland using a gland
wrench and spanner.
125mm – 320mm bore cylinders: refit the retainer and
secure with the hex-headed socket screws (136). Torque
tighten the gland screws.
Chevron Glands Figs. 1, 4 & 8
Ensure that the kit contains seals of the correct group for the
application. Note that the chevron seal assembly comprises a
header ring (137a), several chevrons (137b) and a back-up ring
(137c), as shown.
Fig. 8
Fig. 9
1
RGLL and RKLL gland service kits contain an O-ring (45) which
acts as a static seal between the inner gland and head. This
O-ring may be left in place unless it is faulty. If damaged, the old
O-ring and its back-up washer (134) should be removed from the
gland bearing, and the groove thoroughly cleaned. Lubricate the
replacement parts, and fit the back-up washer into the groove,
followed by the O-ring.
2
Lubricate the gland components, seals, back-up washer and
wear rings using clean system fluid.
3
Fit the wear rings 139b into the gland, and slide the gland (14b),
closed end first, onto the piston rod and press fully into the head (1)
4
Referring to figure 8, identify the header ring (137a) from the set
of chevron seals and slide it, closed end first, onto the piston rod
and into the gland, as shown in figure 4. Insert all the chevrons
(137b) in the same manner, with the lips of the seals facing the
inner (cylinder) end of the gland. When all the chevrons have been
fitted, install the back-up ring (137c) with its angled face against the
last chevron, as shown. Install the back-up washer (138) as shown
in figure 4.
5
Fit the wiperseal (40) into the outer groove of the gland retainer
(27), with the lip facing outwards. Lightly compress and insert the
wear ring into the recess in the inner face of the retainer. Lubricate
the retainer, seal and wear ring.
6
Fit the retainer assembly over the end of the piston rod, and slide
along the rod until it contacts the head.
7
50mm – 100mm bore cylinders: screw the retainer assembly into
the head and tighten securely using a facetype pin wrench.
125mm – 320mm bore cylinders: secure using the hexheaded
socket screws (136) and torque tighten to the figures shown on
page 4.
Servicing Cushion Needle Valves
Fig. 9
MMA cylinders are fitted with a cartridge-type cushion needle
valve adjuster. Leakage from cushion needle valves indicates
that the assembly must be replaced. The replacement assembly
includes a new O-ring.
Removal
Unscrew the needle valve assembly and clean the mounting hole,
paying close attention to the surface on which the O-ring seals.
Installation
Fit the sealing washer (69a) to the cushion needle valve cartridge
(70a). Lightly lubricate the screw threads of the cartridge and
torque to the figure shown in the table. The hexheaded cushion
screw (70b) may be adjusted to provide the required cushioning
performance. Note that the lock nut (70c) must be released before
adjustment and securely retightened afterwards.
