Service; Electrode Replacement - Graco 218-026 Instructions-Parts List Manual

5. Carefully remove the fluid needle assembly (45) from
the rear part of the gun barrel (18). See Fig 15. If the
packing assembly (45a) or insulator (45g) are still in
the barrel, insert the packing removal rod (59d) into
the front of the barrel to gently push them out. Refer
to Fig 16.
NOTE: If the insulator (45g) is removed, be sure to install
it so the insulator end with holes is facing the
packing assembly (45a).
6. Wipe the internal surfaces of the barrel clean with a
soft brush or cloth.
CAUTION
Clean all parts in non–conductive solvent
compatible with the fluid being used, such as xylol
or mineral spirits. Use of conductive solvents can
cause the gun to malfunction.
7. Remove the packing assembly (45a) from the needle
(45b).
NOTE: If the position of the adjusting nut (45c) is
changed, install the adjusting nut to the approxi-
mate dimension shown in Fig 15. (Final adjust-
ment will be made in step 15.) If the spring (45f)
was removed, reinstall it over the nut (45d).
8. Install the new packing assembly (45a).
CAUTION
Carefully screw needle (45b) into new packing
assembly (45a) to avoid damaging the seals.
9. Test the drag on the fluid needle. It should be approxi-
mately 2.5–3 lbs (use a small spring scale to meas-
ure). If the adjustment is out of tolerance, tighten or
loosen the adjusting screw on the packing assembly
(45a) slightly and retest. Continue to adjust until the
tolerance is correct.
10. Install the entire fluid needle assembly (45) into the
gun barrel, from the back of the barrel.
11. Firmly tighten the packing nut (45e) down until it bot-
toms.
CAUTION
When checking the fluid needle movement, DO
NOT move the needle out of the gun barrel more
than 6.35 mm (1/4 in.) to avoid pulling the needle
out of the packing area and damaging the pack-
ings.
12. Install the barrel as described under Barrel
Removal.
13. Install the electrode as described under Electrode
Replacement.

SERVICE

14. Install the air cap assembly and fluid nozzle as
described in Clean the Air Cap and Fluid Nozzle.
15. Trigger the gun to check the needle adjustment. The
air should come fully on before the fluid comes on.
Adjust the needle adjusting nut (45c) until the proper
lead and lag is achieved.
If the fluid comes on too soon , remove the trigger and
back the needle adjusting nut (45c) out (away from
the barrel) slightly.
If the fluid comes on too late, tighten the needle
adjusting nut (45c) slightly (turn towards barrel).
After adjustment is complete, tighten the locking nut
(45d) against the adjusting nut (45c).
KEY
18 Gun Barrel
45 Fluid Needle Assembly
45c Needle Adjusting Nut
Fig 15
KEY
45 Fluid Needle Assembly
45a Needle Packing Assembly
45b Fluid Needle
45c Adjusting Nut
45d Locking Nut
45e Packing Nut
45f Spring
45g Insulator
45g
45a
Fig 16
132.7 mm
(5.2 in.)
45
18
45d
45c
45b
45e
45
45c
45f