SB-2-303-D Page 3
Note
When replacing the fluid tip or
fluid needle, replace both at the
same time. Using worn parts can
cause fluid leakage. Also, replace
the needle packings at this time.
Lightly lubricate the threads of
the fluid tip before reassembling.
Torque to 20 - 25 ft. lbs.
To prevent damage to the fluid
tip (3) or fluid needle (3B), be sure
to either 1 ) pull the trigger and
hold while tightening or loosen-
ing the fluid tip or 2) remove fluid
needle adjusting screw (27) to
relieve spring pressure against
needle collar.
TROUBLESHOOTING
Leakage from the tip can be caused by
sluggish needle travel, improperly mixed
zinc solution, or worn tip and/or needle.
If leakage occurs during application, clean
the gun and hoses out and remove fluid
tip. Inspect the interior seating surfaces.
If large particles appear to be imbeded
into the tip seat, scrape the surfaces with
a blunt object. Then, attempt to remove
agglomerates from the balance of solution
by straining.
Fluid Tip – If large imbedded clumps
cannot be removed, or if the tip seating
surface is worn, it will be necessary to
replace the tip and needle. Satisfactory
operation depends on the unique DeVil-
biss tip design, smooth needle shaft, and
lubricated and properly adjusted packings.
A. Trigger Points
B. Packing
C. Adjusting Valves
D. Threads
A
B
A
C
D
In order to insure proper operation,
replace these parts when tip leakage oc-
curs due to wear:
MBC-4397-D
Fluid Tip, Needle & Gasket Kit
(Zinc waterborne gun)
AV-650-D Fluid Tip
MBC-496-DEX Needle and
AV-1 Gasket
(Zinc solvent-based gun)
MB-135
pre-lubricated leather packings (3)
(both guns)
SPRAY GUN LUBRICATION
Daily, apply two drops of •SSL-10 spray
gun lube (see Accessories) at trigger
bearing stud (29) and the stem of the air
valve (19) where it enters the air valve
assembly. The shank of the fluid needle
(3B) where it enters the packing nut (7)
should also be oiled. The fluid needle
packing (3A) should be kept soft and pli-
able by periodic lubrication. Make sure
the sprayhead (6) and retaining ring (1)
threads are clean and free of foreign mate-
rial. Before assembling retaining ring to
sprayhead, clean the threads thoroughly,
then add two drops of SSL-10 spray gun
lube to threads. The fluid needle spring
(26) and air valve spring (20) should be
coated with a very light grease, making
sure that any excess grease will not clog
the air passages. For best results, lubricate
the points indicated, daily.
• Material Safety Data Sheet available from
DeVilbiss upon request.
