Service
16
3A4238B
Service
Repairing the Air Valve
Tool Required
•
Torque wrench
•
Torx (T20) screwdriver or 7 mm (9/32 in.) socket
wrench
•
Needle-nose pliers
•
O-ring pick
•
Lithium base grease
NOTE:
Air Valve Repair Kits are available. Order Kit
236273 for models with aluminum center housing. Parts
included in Kit 236273 are marked with
. Use all the
parts in the kit for the best results.
Disassembly
1.
Relieve the pressure.
2.
With a Torx (T20) screwdriver or 7 mm (9/32 in.)
socket wrench, remove the six screws (3), air valve
cover (2), and gasket (4). See F
3.
Move the valve carriage (5) to the center position
and pull it out of the cavity. Remove the valve block
(7) and o-ring (6) from the carriage. Using a
needle-nose pliers, pull the pilot block (18) straight
up and out of the cavity. See F
4.
Pull the two actuator pistons (11) out of the bearings
(12). Remove the u-cup packings (10) from the
pistons. Pull the pilot pins (16) out of the bearings
(15). Remove the o-rings (17) from the pilot pins.
See F
5.
Inspect the valve plate (8) in place. If damaged, use
a Torx (T20) screwdriver or 7 mm (9/32 in.) socket
wrench to remove the three screws (3). Remove the
valve plate (8). See F
6.
Inspect the bearings (12, 15) in place. See F
The bearings are tapered and, if damaged, must be
removed from the outside. This requires disassem-
bly of the fluid section. See page 24.
7.
Clean all parts and inspect for wear or damage.
Replace as needed. Reassemble.
Reassembly
1.
If you replaced the bearings (12, 15),
reinstall as
explained on page 24. Reassemble the fluid
section.
2.
On models with aluminum center housing, install the
valve plate seal (55
) into the groove at the bottom
of the valve cavity. The rounded side of the seal
must face down
into the groove. See F
3.
Install the valve plate (8) in the cavity, seal down.
Install the three screws (3), using a Torx (T20)
screwdriver or 7 mm (9/32 in.) socket wrench.
Tighten until the screws bottom out on the housing.
See F
4.
Install an o-ring (17
) on each pilot pin (16). Grease
the pins and o-rings. Insert the pins into the
bearings (15),
narrow
end first. See F
5.
Install a u-cup packing (10
) on each actuator
piston (11), so the lips of the packings face the
narrow
end of the pistons. See F
6.
Lubricate the u-cup packings (10
) and actuator
pistons (11). Insert the actuator pistons in the
bearings (12),
wide
end first. Leave the narrow end
of the pistons exposed. See F
7.
Grease the lower face of the pilot block (18
) and
install so its tabs snap into the grooves on the ends
of the pilot pins (16). See F
8.
Grease the o-ring (6
) and install it in the valve
block (7
). Push the block onto the valve carriage
(5). Grease the lower face of the valve block. See
F
9.
Install the valve carriage (5) so its tabs slip into the
grooves on the narrow end of the actuator pistons
(11). See F
10. Align the valve gasket (4
) and cover (2) with the
six holes in the center housing (1). Secure with six
screws (3), using a Torx (T20) screwdriver or 7 mm
(9/32 in.) socket wrench. Torque to 52-60 in-lb
(5.6-6.8 N•m). See F
