Repair Air Motor; Disassemble The Air Motor; Reassemble The Air Motor - Graco Dyna-Star 26A938 Instructions Manual

Repair Air Motor

Refer to Parts, on page 16 for this section.
NOTE: Air Motor Seal Kits are available. To order the
correct kit for the pump, see page 18. Parts included in
the kit are marked with an (*). For best results, use all of
the parts in the kit.

Disassemble the Air Motor

1. Stop the pump in the middle of its stroke. Follow
Pressure Relief Procedure, page 10.
2. Disconnect the air lines.
3. Use a 10 mm socket wrench to remove four screws
(18), then remove the air valve (17) and gasket (16).
4. Remove four screws (18) to remove the manifold
(15) and gasket (14).
5. Use a 10 mm socket wrench to remove the pilot
valves (19) from the top and the bottom covers.
6. Remove the lift ring (31) and o-ring (32) from the
center of the top cover.
7. Remove the tie bolts (10).
8. Remove the top cover and take out the o-ring (9).
9. Remove the cylinder (11).
10. Slide the piston assembly (5) straight up and off of
the bottom cover.
NOTICE
To prevent damage, do not attempt to take apart the
piston assembly (5).
11. Remove the o-ring (8) from around the piston.
12. Remove the retaining ring (4), the u-cup seals (3,
33), and the o-ring (9) from the bottom cover.

Reassemble the Air Motor

NOTE: Use NLGI No. 1, bentone-based grease for
lubricant.
Manual 3A7718A
For easier reassembly, begin with the top cover (13)
turned over on the workbench then reassemble the air
motor from top to bottom.
1. Lubricate and install the o-ring (9) onto the top cover
(13).
2. Lubricate the inside of the cylinder (11) then lower
the cylinder (11) onto the top cover (13).
3. Lubricate then install the o-ring (8) around the
piston assembly (5).
4. Slide the piston assembly (5) down onto the cylinder
(11), making sure that the o-ring (9) stays in place.
5. Lubricate then install a new u-cup seal with flange
(33) in the bottom of the bearing located in the
bottom cover (1), making sure that the u-cup faces
up and the flange faces down. Then lubricate and
install a new u-cup seal (3) in the top of the bearing
making sure that the u-cup lips are facing up (F
8).
33
Lips Face Up
F . 8
IG
6. Install the retaining ring (4).
7. Lubricate and install the o-ring (9) onto the bottom
cover (1).
8. Place the bottom cover (1) carefully onto the
cylinder (11), sliding the rod through the bearing.
The manifold surfaces of the top and bottom covers
must align.
9. Install the tie bolts (10) and hand tighten.
Repair
.
IG
4
3
Lips Face Up
13