TRUCK SERVICE MANUAL
FUEL SYSTEM
spring. Use thrust washer, Part No. 188713, with teflon
stop collar, Part No. 188714.
Air Fuel Control
Fuel pumps with Air Fuel Control (AFC) must be
mounted to Swivel Vise, ST-302, with front cover
Mounting Plate, No. 3375133. Fig. 5-10.
Disassembly
1. Remove AFC cover plate. Fig. 5-24.
2. Carefully lift bellows away from sealing surface
around AFC cavity and pull bellows, piston and plunger
assembly from AFC barrel. Fig. 5-25.
3. Remove AFC bellows spring and steel shim between
spring and fuel pump housing. Fig. 5-26.
4. Remove AFC barrel retaining ring. Fig. 5-27.
5. Remove AFC barrel, discard barrel "O" rings.
6. Remove plunger jam nut and unscrew plunger from
Fig. 5-24, F5301. Removing AFC side cover plate
center bolt.
7. Remove center bolt jam nut, washer, and gasket;
remove bellows from piston. Fig. 5-9.
8. Slide "Glyd" ring and "O" ring seal assembly from the
AFC throttle plunger.
AFC Assembly Installation
1. Lubricate barrel "O" rings and Install in grooves in
barrel, press barrel Into housing and secure with snap
ring.
Note: Lightly coat all "O" rings with a 50-50 mixture of a
lubricating oil additive (such as STP) and clean
lubricating oil just before installation. Fig. 5-27.
2. Place steel shim in bellows spring seat groove.
3. Install spring with small end in housing. Fig. 5-26.
4. Lubricate "O" ring and install over throttle plunger
using installation tool No. 3375146 then install "Glyd"
ring over tool and plunger on top of "O" ring. Install
plunger assembly in seal-ring forming tool No. 3375147,
leave in tool and complete Steps 5 through 7.
Fig. 5-25, F5302. Removing AFC bellows and piston
5. Assemble center bolt, gasket, washer (rounded edge
assembly
toward bellows), bellows (with part number toward
piston), piston, washer and jam nut.
6. Hold assembly by hex on center bolt and center
bellows piston and washers, without twisting bellows
tighten jam nut to 30 to 40 in-lbs [3.4 to 4.5 Nm] torque.
Make sure parts are centered.
7. Wrap plunger threads with teflon tape and screw
plunger into center bolt until threaded end of plunger is
flush with center bolt surface. Install jam nut, leave
loose.
Fig. 5-26, F5303. Removing AFC bellows spring and
washer
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