DETROIT DIESEL 53
Fuel Injector 2.1.1
Then raise the spring above the stop pin with a screw driver and withdraw the pin. Allow the spring to rise gradually.
Refer to Fig. 24 and remove the plunger follower, plunger and spring as an assembly.
Invert the fixture and, using socket J 4983-01, loosen the nut on the injector body (Fig. 25).
Lift the injector nut straight up, being careful not to dislodge the spray tip and valve parts. Remove the spray tip
and valve parts from the bushing and place them in a clean receptacle until ready for assembly.
When an injector has been in use for some time, the spray tip, even though clean on the outside, may not be pushed
readily from the nut with the fingers. In this event, support the nut on a wood block and drive the tip down through the
nut, using tool J-1291-02 as shown in Fig. 26.
Refer to Fig. 36 and remove the spill deflector. Then lift the bushing straight out of the injector body.
Remove the injector body from the holding fixture. Turn the body upside down and catch the gear retainer and
gear in your hand as they fall out of the body.
Withdraw the injector control rack from the injector body. Also remove the seal ring from the body.
Clean Injector Parts
Since most injector difficulties are the result of dirt particles, it is essential that a clean area be provided on which to
place the injector parts after cleaning and inspection.
Wash all of the parts with clean fuel oil or a suitable cleaning solvent and dry them with clean, filtered compressed air.
Do not use waste or rags for cleaning purposes. Clean out all of the passages, drilled holes and slots in all of the injector
Carbon on the inside of the spray tip may be loosened for easy removal by soaking for approximately 15 minutes in a
suitable solution prior to the external cleaning and buffing operation. Methyl Ethyl Ketone J 8257 solution is
recommended for this purpose.
Clean the spray tip with tool J 9464-01 Fig. 27).
CAUTION: Care must be exercised when inserting the carbon remover J 9464-01 in the
spray tip to avoid contacting the needle valve seat in the tip.
Wash the tip in fuel oil and dry it with compressed air. Clean the spray tip orifices with pin vise J 4298-1 and the proper
size spray tip cleaning wire. Use wire J 21460 to clean .0055 " diameter holes and wire J 21461 to clean .006 " diameter
holes (Fig. 28).
Before using the wire, hone the end until it is smooth and free of burrs and taper the end a distance of 1/16" with stone
J 8170. Allow the wire to extend 1/8 " from tool J 4298-1.
Fig. 30. Cleaning Injector
Fig. 31. Sealing Surfaces
Fig. 32. Examining Surface
Nut Spray Tip Seat
Which May Require Lapping
with a Magnifying Glass