2012/12/20 Caterpillar

Off-Highway Truck/Tractor:

777 (S/N: 84A1-UP)

777B (S/N: 4YC1-UP)

777C (S/N: 4XJ1-UP)

777D (S/N: FKR1-UP)

777D (S/N: AGC1-UP)

777D (S/N: 3PR1-UP)

777F (S/N: JRP1-UP)

Service Magazine SEPD1482, 16 08 2012, "Hoist Cylinder Group Piston Has Been Improved on 777D Off-Highway Trucks". Disregard this article. See the article that follows.

ReferenceDisassembly and Assembly, "Hoist Cylinder - Remove and Install".

Description of Change: The new piston provides proper clearance between the wear ring and piston. The service life of the piston and performance of the hoist cylinder group will be improved.

Adaptable To: The new 8J-9445 Piston and 336-5288 Hydraulic Cylinder Seal Kit are part of 300-0688 Hoist Cylinder Gp.

Illustration 1	g03174816

The new 8J-9445 Piston (1) is adaptable to the machines: 84A1-UP, 4YC1-UP, 4XJ1-UP, AGC1-UP, 3PR1-UP, FKR1-395, and JRP1-1900 and effective in production with the machines FKR396-UP and JRP1901-UP.

Use the following procedure to rework the piston for the machines 84A1-UP, 4YC1-UP, 4XJ1-UP, FKR1-395, AGC1-UP, 3PR1-UP, and JRP1-1900:

Show/hide table



Illustration 2	g03173139
(A) 183.87 ± 0.03 mm (7.239 ± 0.001 inch)

1. Remove piston (2) from the hoist cylinder group and discard the piston seals.

2. Grind piston (2) to dimension (A) as shown in Illustration 2.

3. Install the reworked piston (2) back to the hoist cylinder group with the new piston seals.