819.4470
14
Service
Repairing the Air Valve
Tools Required
D
Torque wrench
D
Torx (T20) screwdriver or 7 mm socket wrench
D
Needle-nose pliers
D
O-ring pick
D
Lithium base grease
NOTE:
Air Valve Repair Kit 819.4274 is available. Refer to
page 23. Parts included in the kit are marked with a
symbol, for example (4
{
). Use all the parts in the kit
for the best results.
Disassembly
To reduce the risk of serious injury whenever you are
instructed to relieve pressure, always follow the
Pressure
Relief Procedure
on page 10.
Warning
1.
Relieve the pressure.
2.
With a Torx (T20) screwdriver or 7 mm socket wrench,
remove the six screws (3), air valve cover (2), and gas-
ket (4). See Fig. 8.
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. 9.
4.
Pull the two actuator pistons (11) out of the bear-
ings (12). Remove the u-cup packings (10) from the pis-
tons. Pull the pilot pins (16) out of the bearings (15). Re-
move the o-rings (17) from the push pins. See Fig. 10.
5.
Inspect the valve plate (8) in place. If damaged, use a
Torx (T20) screwdriver or 7 mm socket wrench to re-
move the three screws (3). Remove the valve plate (8)
and seal (9). See Fig. 11.
6.
Inspect the bearings (12, 15) in place. See Fig. 10. The
bearings are tapered and, if damaged, must be removed
from the outside. This requires disassembly of the fluid
section. See page 20.
7.
Clean all parts and inspect for wear or damage. Replace
as needed. Reassemble as explained on page 15.
Torque to 5.6–6.8 N
S
m.
Fig. 8
3
2
4†
2
2
02644B
18
{
5
Fig. 9
1
2
See Detail at right.
Grease.
3
Grease lower face.
1
{
7
{
6
5
2
3
3
04165B
11
