Replace End Cap And Air Piston Assembly - Graco GX-8 Operation, Parts, Service, Repair

5. OPEN safety stop.
6. To install mixing module, hold down gun
trigger and slide module over end of valving
rod. Make sure to align keypin with slot in
gun block. Keep gun trigger depressed and
proceed to step 7.
7. To install PCD, hold gun trigger in and
place PCD over mixing module. If installing
a fan tip, position PCD according to which
spray direction is needed (vertical or hori-
zontal). Keep gun trigger depressed and
proceed to step 8.
Parts must align properly or chemical flow
from gun block ports will not enter mixing
module when gun is triggered.
8. Install PCD retainer:
a. With gun trigger depressed, thread
PCD retainer in place by hand.
b. Use 10 in. adjustable wrench to care-
fully tighten PCD retainer until it is snug
enough to ensure no leak will occur.
c. Release gun trigger.
CAUTION
To avoid damage to module and gun block,
do not overtighten mixing module retainer.
9. Install air cap and tighten by hand.
10. Adjust valving rod (see Valving Rod
Adjustment, page 11).
311338B
Replace End Cap and Air
Piston Assembly
End Cap
End Cap/Safety
O-Ring
Stop Assembly
Retaining
Cylinder
Ring
Cup Seal
Piston
O-Ring
Piston
Piston
Spring
F . 16: End Cap and Air Piston Assembly
IG
1. Clean gun (see Clean Spray Gun Proce-
dure on page 15).
2. Disconnect air supply from gun.
3. Use 5/16 in. wrench to loosen packing nut
3 or 4 turns (remove nut completely if rear
seal needs to be replaced).
4. Remove gun block:
a. Use 5/16 in. nut driver to remove gun
block mounting screw.
b. Carefully slide gun block away from
valving rod and air cylinder. If dried
chemical has built up on gun block,
remove dried chemical to make removal
easier.
c. Remove valving rod and jam nut (see
Remove Check Valve, page 17):
Repair
#8 Socket Head
Cap Screw
19