SECTION 6: MAINTENANCE
CAS40P 40 CFM / 100 PSIG
PAGE - 54
®
An Oshkosh Corporation Company
J.
Refer to
Section 6.4.6
. To dismantle head, remove
low pressure hold-down covers and high pressure
hold-down covers by removing cap screws. Lift out
low pressure cages and high pressure cages. Low
pressure valves and high pressure valves can be
lifted out as well as the low pressure seat gasket
(
Figure 6-7
, [
V
]), and high pressure seat gasket (
Fig-
ure 6-7
, [
D
]).
K.
Refer to
Section 6.4.6
. To dismantle valves, place
valve in a soft jaw vise and remove center screw.
Valves are now free to take apart. Clean all parts
thoroughly. Valve plates and seats must be smooth
and flat; they can sometimes be resurfaced by rub-
bing on fine emery cloth held on a smooth surface.
6.4.13.1 FITTING AND REASSEMBLING
Clean all parts thoroughly before assembling. Refer
to
Table 6C: Compressor Torque Values
for proper
torque specifications for assembling parts.
A.
Crankshaft — Base
Be sure base is free of all metal chips and dirt. Insert
crankshaft and oil feeder ring only into base. Assem-
ble end cover and tighten end cover bolts evenly.
End cover gaskets or shims are furnished in three
thicknesses, and the proper combination must be
selected so that crankshaft can be “spun” in the bear-
ings without “end play”. Also see that oil feeder ring
turns freely within the guide lugs in the base. Then
remove crankshaft. For additional guidance, refer to
Section 6.4.7
.
B.
Piston — Cylinder
Check fit before assembling pistons to connecting
rods. Pistons without rings should slide through the
cylinder of their own weight and holding the skirt of
the piston with the two thumbs there should be no
appreciable side motion at any point of piston travel.
Scored cylinders or pistons should be replaced. For
additional guidance, refer to
Section 6.4.8
.
C.
Wrist Pins should be
“
tap
”
fitted by hammer. See
that roll pin holes are in line.
D.
Wrist Pin — Needle Bearing
Fit so that piston can be “rocked” with three fingers:
the thumb on one side and index and middle fingers
on the other. The piston should not rock of its own
weight. Drive roll pin into wrist pin when piston and
wrist pin holes are in line and piston is assembled to
IMPORTANT
Badly worn parts including springs,
which lose tension after considerable
use should be replaced.
TABLE 6C: COMPRESSOR TORQUE VALUES
BOLTS
SIZE
GRADE
TORQUE
(ft.-lb.)
POSITION
1/4-28 NF
8.8
8
LP. Valve
Nut
3/8-24 NF
8.8
40
Cylinder to
Base Bolt
5/16-18
NC
8.8
10
Head to
Cylinder Bolt
10.9
Connecting
Rod Bolt
8.8
LP & HP
Hold Down
Bolt
5/16-24 NF
8.8
12
Flywheel
Bolt
7/16-14
NC
8.8
43
Cover Bolt
Manual #99905382 Rev 02
(JUNE 2018)
