21
308-262
Air Motor Service
Cylinder and Piston Service
Disassembly
1.
Disconnect the air motor (1) from the displacement
pump (100), as explained on page 15.
2.
Remove the six screws (25 and 42) holding the
bottom cylinder cap (4) to the cylinder (2). Lift the
cylinder off the cap to expose the piston (14). See
Fig. 11.
3.
Pull the piston (14) and piston rod (18) out of the
outlet housing (18) and bottom cylinder cap (4).
4.
Remove the piston o-ring (32*). Insert a punch in
the hole at the end of the piston rod (18) to hold it
steady, and unscrew the nut (35) from the rod.
Remove the two washers (27), o-ring (30*) and
piston (14).
5.
Stand the cylinder (2) upright. Remove the six
screws (25 and 42) and lift off the top cap (3).
6.
Examine the inner surface of the cylinder for
scoring or damage.
7.
Remove the large o-ring (22*) and two small
o-rings (34*) from the inside of the top cylinder cap
(3). Repeat for the bottom cylinder cap (4).
Reassembly
1.
Grease the large o-ring (22*) and the two small
o-rings (34*) and install them on the top cylinder
cap (3). Repeat for the bottom cylinder cap (4).
See Fig. 11.
2.
Install the top cap (3) on the cylinder (2). Be sure
that the large o-ring (22*) does not roll out of the
groove. Install two M4 screws (25) in the square
section of the cap and four M5 screws (42) in the
tabs. Torque the two M4 screws (25) to 14 to 17
in-lb (1.6 to 1.9 N-m) and the four M5 screws (42)
to 35 to 45 in-lb (4.0 to 5.1 N-m).
3.
Install a washer (27), an o-ring (30*), the piston
(14),
with the chamfer facing down toward the
o-ring (30), and a washer (27) on the piston rod
(17). Screw the self-locking nut (35) onto the rod.
Install the o-ring (32*) on the piston (14), and
lubricate the o-ring.
4.
Grease the piston rod (17) and the inner wall of the
cylinder (2).
5.
Insert the piston rod (17) into the bottom cap (4)
and the outlet housing (18), being careful not to
damage the u-cup packing (19) inside the cap.
6.
Install the cylinder (2) down over the piston (14).
Be sure that the large o-ring (22*) does not roll out
of the groove. Install the screws (25 and 42) in the
bottom cap (4), as explained in step 2.
7.
Reconnect the air motor (1) to the displacement
pump (100), as explained on page 15.
