Graco GX-8 Operation, Parts, Service, Repair page 23

5. OPEN safety stop.
6. Use 9/64 in. ball point hex key to remove socket
head cap screw that holds air cylinder to handle
(F . 16).
IG
7. Use retaining ring 45° pliers to remove retaining ring
that holds end cap in place inside air cylinder.
8. Remove end cap/safety stop assembly and piston
spring:
a. Pull safety stop and attached end cap out of air
cylinder.
b. Remove piston spring located inside cylinder.
Be sure to retain spring for re-installation.
NOTE: Force will be required to remove end cap
because ring is tightly compressed.
9. Inspect end cap ring. Replace if damaged. Apply
light coating of Lubriplate grease and install new
end cap ring.
NOTE: Skip steps 11-13 and go to step 14 if only end
cap ring and cup seal need to be replaced.
a. Remove piston/rod assembly:
Use gun block mounting screw (screw that
holds gun block to bracket) to aid in removal of
piston.
b. Look into rear of air cylinder and thread mount-
ing screw into center hole of piston at least 4 full
turns.
c. Use 6 in. pliers to grab mounting screw and pull
piston rod assembly out of air cylinder.
d. Inspect ring and replace if damaged. Apply light
coat of Lubriplate grease and install new ring.
10. Inspect air cylinder cup seal. If air escapes around
piston rod during operation, remove and replace
cup seal located in front of air cylinder. Lubricate
new cup seal with Lubriplate grease and install it.
Make sure cup faces toward rear of cylinder.
11. Insert piston and rod assembly into air cylinder. Be
careful not to damage cup seal in front face of air
cylinder as rod passed though. Remove gun block
mounting screw from piston.
12. Disassemble safety stop mechanism:
311338N
a. Use 5/64 in. hex key to remove two set screws
from knob.
b. Slide knob off stop pin and retain stop pin
spring.
c. Pull shaft out of end cap (F
13. Remove cup seal from end cap and inspect for
damage. Remove if damaged. Apply light coat of
Lubriplate grease and install new end cap ring.
O-ring
Spring
End Cap
Cup Seal
Stop Pin
F . 17: End Cap/Safety Stop Assembly
IG
14. Reassemble safety stop mechanism:
a. Insert stop pin into end cap hole.
b. Slide spring and knob onto stop pin.
c. Use 5/64 in. hex key to reinstall two set screws
into knob. Ensure knob is secure.
15. Reinstall end cap/safety assembly and piston
spring:
a. Insert piston spring and align over raised center
of piston.
b. Line up raised center of end cap with spring and
insert end cap into air cylinder.
c. Press end cap until it moves past retaining ring
groove in cylinder.
d. Maintain pressure on end cap. Ensure groove
remains visible.
16. Use retaining ring 45° pliers to reinstall retaining
ring into groove.
Repair
. 17).
IG
Knob
Set Screws
23