GMC 4000 Series Service Manual page 382

TORQUE WRENCH
TUBING CLAMP!
W
ADAPTER
/T / W ^
TUBE N U T P L i || _
n
V
w r y NOZZLE HOLDER
T I G H T E N I N G N U T A T N O Z Z L E
H O L D E R
Figure 2 6 — Torque Wrench Adapter for Tightening
Nuts on H igh Pressure Lines (Typical)
preformed tubing of the original material. All lines
must be of equal overall length. Tubing inside diam­
eter must be 0.084-inch, and wall thickness must
be 0.083-inch. The torque wrench adapter (J-22975)
shown in figure 26 must be used to assure correct
torque at all tube nuts. Torque nuts to 20 to 25
foot-pounds. NUTS MUST NOT BE OVER-TIGHT­
ENED since this may com press the tubing and re­
sult in reduced inside diameter.
IMPORTANT: Refer to figure 27 for arrange­
ment of fuel high pressure lines. As lines are s e ­
lected and placed in respective positions, dip each
end of line in fuel oil and start tube nuts at pump
and injection nozzles with fingers. Each nut should
be turned a minimum of four full turns before u s­
ing wrenches. LINES MUST NOT BE FORCED OR
BENT INTO POSITION.
1. Remove dust cap from threaded connections
at injection nozzle and at outlet port in injection
pump, then place the high pressure line in place
so that fittings on both ends line up squarely with
G M C S E R V I C E M A N U A L
FUEL INJECTION SYSTEM— TORO-FLOW ENGINE
ADAPTER!
TORQUE
WRENCH
HYDRAULIC
L HEAD
T I G H T E N I N G N U T A T H Y D R A U L I C
H E A D
Figure 2 8 — Delivery V a lve a n d Retaining Parts
Figure 2 7 — Fuel H igh Pressure Line and Clam p Installation
respective threads at both the injection pump and
the nozzle holder. Start tube nuts at both ends,
then when lines are seated use torque wrench and
adapter (J-22975) (fig. 26), to tighten nut at hy­
draulic head to 20 to 25 foot-pounds torque. Tighten
nuts at nozzles 20 to 25 foot-pounds torque.
2. Assem ble rubber line clamps and metal
backing plates with the rolled edges of backing
plates crossw ise of lines. Refer to figure 27.
3. Finally, tighten the line clamp bolts to
firmly support lines and prevent vibration. When
clamp bolts are properly tightened, the metal parts
of clamp plates must not touch fuel lines. At least
0.060 inch clearance must exist between edge of
clamp and surface of each line.
FUEL DELIVERY VALVE
REPLACEMENT
IMPORTANT: Before disassembly of fuel de­
livery valve, make sure cap gasket and valve seat
gaskets are available for replacement.
REMOVAL (Fig. 28)
1. Remove equipment as necessary to provide
access to the hydraulic head assembly. Use solvent
Sec. 6M
Page 371