Mack MP7 - Page 130

REPAIR INSTRUCTIONS, PART 1
Page 119
5. Injector Removal — 28 mm (Short) Yoke
Use care when removing the unit injector
because the injector hold-down is not secure and
could fall off if not held in place.
a. Initially attempt to remove the unit
injector using the standard injector
puller (tool No. 9990006).
b. If the unit injector cannot be removed
using the standard puller, proceed to
using the heavy-duty puller (tool
No. J 48922) by positioning the forks of
the heavy-duty puller (tool No. J 48922)
under the lip on the unit injector. Secure
the puller by sliding the lock collar down
over the forks. Remove the injector
from the cylinder head using hand
tools. The injector must be lifted out
along with the hold-down yoke.
122
Figure 122 — Removing Injector with the Heavy Duty
Unit Injector Puller (Tool No. J 48922)
If excessive combustion leakage has resulted in
the copper sleeve being stuck-fast to the unit
injector by carbon, the unit injector must be
replaced. The condition is found when the unit
injector is removed and the copper sleeve comes
out with the injector.
6. Injector Removal — 38 mm (Tall) Yoke
Use care when removing the unit injector
because the injector hold-down is not secure and
could fall off if not held in place.
a. Use a pry bar (tool No. 9998511) or
equivalent, under the hold-down or
injector lip and pry up to remove the
injector.
123
Figure 123 — Removing Injector with a Pry Bar
(Tool No. 9998511)
b. If the injector cannot be removed using
the pry bar, proceed as follows:
i. Depending on which injector is
stuck, remove the unit injector
from the companion cylinder (i.e.,
if the injector in cylinder No. 1 is
stuck, remove the injector from
cylinder No. 6). Use the
appropriate flywheel turning tool to
rotate the engine crankshaft to
position the camshaft at TDC.
Next, rotate the engine from TDC
to the appropriate camshaft mark
to position the piston at the
companion cylinder at TDC, see
the following table. Confirm the
piston is at the top of the cylinder
by inserting a 40 cm (16 inch)
piece of straight stiff wire into the
injector hole of the companion
cylinder.