Manual

15
Service
Repairing the Air Valve
Tools Required
D Torque wrench
D Torx screwdriver or 8 mm (5/16”) socket wrench
D Needle-nose pliers
D O-ring pick
D Lithium base grease
NOTE: Air Valve Repair Kit 784–90616 is available.
Disassembly
WARNING
To reduce the risk of serious injury whenever you are
instructed to relieve pressure, always follow the Pres-
sure Relief Procedure on page 11.
1. Relieve the pressure.
2. With a torx screwdriver or 8 mm (5/16”) socket
wrench, remove the six screws (3), air valve cover (2),
and gasket (4). See Fig. 7.
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 Fig. 8.
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). Re-
move the o-rings (17) from the push pins. See Fig. 9.
5. Inspect the valve plate (8) in place. If damaged, use a
torx screwdriver or 8 mm (5/16”) socket wrench to
remove the three screws (3). Remove the valve plate
(8) and seal (9). See Fig. 10.
6. Inspect the bearings (12, 15) in place. See Fig. 9. The
bearings are tapered and, if damaged, must be removed
from the outside. This requires disassembly of the fluid
section. See page 21.
7. Clean all parts and inspect for wear or damage. Re-
place as needed. Reassemble as explained on page 15.
Reassembly
1. If you replaced the bearings (12, 15), reinstall as
explained on page 21. Reassemble the fluid section.
2. Install the valve plate seal (9{) into the groove at the
bottom of the valve cavity. The rounded side of the
seal must face down into the groove. See Fig. 10.
3. Install the valve plate (8) in the cavity. The plate is
reversible, so either side can face up. Install the three
screws (3), using a torx screwdriver or 8 mm (5/16”)
socket wrench. Tighten until the screws bottom out on
the housing. See Fig. 10.
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 Fig. 9.
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 Fig. 9.
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 Fig. 9.
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 Fig. 8.
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 Fig. 8.
9. Install the valve carriage (5) so its tabs slip into the
grooves on the narrow end of the actuator pistons (11).
See Fig. 8.
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 screwdriver or 8 mm (5/16”) socket
wrench. Torque to 38–43 in-lb (4.3–4.9 N.m). See Fig.
7.