2012/07/20 Caterpillar

Off-Highway Truck:

793F (S/N: SND1-UP; SSP1-UP)

795FSeries AC (S/N: ERM1-UP)

797F (S/N: LAJ1-UP; WSP1-UP)

Description of Change: The new high-pressure fuel pumps have improved internal sealing because of the following design changes at the joints between the manifold and pump housings. The new pumps also have improved designs for the check valves.

• Bolts with flange-type heads are now used for the manifold to pump housing joint instead of the previously used socket heads.

• Dual seals protect the bolts at the manifold to pump housing joint from exposure to fuel

• Passages inside of the pump housing return fuel to the low-pressure inlet if a leak at the high-pressure seal occurs.

• The threads of the inlet check valve are now manufactured with a process that improves reliability.

Illustration 1	g03033684
(1) Manifold (2) Pump housing (3) Bolt with flange-type head

Illustration 2	g03036116
Cutaway view of the pump (1) Manifold (2) Pump housing (4) Barrel (5) Check valve

Illustration 3	g03036137
(4) Barrel (6) Inner seal (7) Outer seal (8) Passage for fuel

Illustration 4	g03036140
(4) Barrel (5) Check valve

Adaptable To: The new high-pressure fuel pumps are adaptable to C175 Off-Highway Truck Engines back to first production.