TRUCK SERVICE MANUAL
FUEL SYSTEM
Note: All tests on test stand are performed without a
b. Hold injector plunger down against its seat in
screen on injector.
injector cup with injector in a vertical position.
13. Assemble ST-708 Burnishing Tool into test stand
Assembly may be held in hand, do not place in
injector inlet connector. Retract the needle by
test stand holding device. Fig. 6-1-111.
pulling out small knob. With needle retracted
Note: Be sure ST-708-1 Needle is retracted.
ST-708 tool may be left in connector during all
c. Turn on test stand, and adjust pressure to 150
test operations.
psi [1034 kPa .
Note: Injector delivery is adjusted by burnishing the inlet
d. Check orifice plug inlet opening of Service Tool
orifice plug with ST-708 instead of changing the plug.
3375086, ST-1058 Body for leakage past ball
The replaceable needle point, ST-708-1, is the
valve.
burnishing member.
Note: Make sure plunger is seated in cup.
14. Install connector and ST-708 tool into Service
e. If leakage is observed, the ball must be
Tool 3375086, ST-1058 Body inlet by screwing in
replaced. Slight seepage is not harmful.
the large knob section. Fig. 6-1-112.
Fig. 6-1-111, F60213. Check leakage at inlet port
6. Install injector in Service Tool 3375086, ST-1058
Fig. 6-1-112, F60214. ST-708 installed in inlet
or Body. Disconnect Inlet pressure line from
connection
drain connection of body. Remove injector
plunger.
7. Seat injector so injector inlet aligns with body
inlet hole after injector adapter is located in
sleeve.
8. The location screw must seat in hole of adapter.
9. Check to be sure injector inlet is centered in
body inlet hole to prevent breaking ST7081
Burnishing Tool points when installed later.
10. Install spring and plunger into injector.
11. Assembly retainer plate over injector with pins
engaging in body.
12. Position injector in test stand with correct
adapter link. See Table 611.8.
Table 6-1-18: ST-790 Test Stand Link Data PT (type
Fig. 6-1-113, F60215. Assemble ST-70a tool to pot
D)
Length
Inch [mm]
Link Marking
6.5 [165]
ST-790-331
479
