Usage:
D11N (4HK, 74Z) Track-Type Tractors;
776B (6JC),
776C (2TK),
784B (5RK) Tractors;
777B (4YC),
777C (4XJ),
785 (8GB),
785B (6HK),
789 (9ZC),
789B (7EK),
793 (3SJ),
793B (1HL) Trucks;
994 (9YF) Wheel Loaders;
5130 (7TJ, 5ZL),
5230 (7LL) Excavators
Reference: Service Magazine; May 12, 1986; Page 5; "Cylinder Liner Seat Insert Available".
Description of Change: Two new stainless steel liner seat inserts are available. These new inserts will allow cylinder blocks with liner seat cracks to be repaired that formerly could not be salvaged.
Adaptable To: The 7W-5949 Liner Seat Insert is 3.175 mm (.1250 in) thick. The new 120-4334 Liner Seat Insert is 5.080 mm (.2000 in) thick and the new 120-4337 Liner Seat Insert is 7.620 mm (.3000 in) thick.
The new 120-4334 Liner Seat Insert should be used when liner seat cracks extend into the block up to 5.0 mm (.20 in). For cracks deeper than 5.0 mm (.20 in), use the 120-4337 Liner Seat Insert regardless of the crack depth. While this in a change from prior recommendations, 5 years of successful field experience has proven it to be unnecessary to replace the cylinder block when a crack extends deeper than the insert.
NOTE: A cylinder block with cracks that extend into a bolt hole or water passage is not salvageable.
The 120-4334 and 120-4337 Liner Seat Inserts use a press fit installation method (see Installation Procedure in this article). This is different from the original slip fit method used with 7W-5949 Liner Seat (see the Reference Article). The 7W-5949 Liner Seat Insert should NOT be installed using the press fit method that follows.
Installation Procedure
1. Measure the thickness of the liner seat insert and counterbore block to the same depth. Refer to the illustration for outside diameter and radius dimensions of the counterbore.
Dimensions to machine counterbore into cylinder block. (1) 212.051 ± 0.025 mm (8.3485 ± .0010 in) Diameter. (2) Depth of counterbore should equal thickness of insert. (3) 0.63 ± 0.13 mm (.025 ± .005 in) Radius.
2. Clean insert and all mating surfaces prior to installation of insert.
3. Apply 4C-9506 Sealant only to outside of insert.
4. Install insert, making sure chamfer is facing in toward block.
5. The insert must be installed with a projection of + 0.025 mm (.0010 in) -0.000 mm (.0000 in).
6. Install cylinder liner. The projection of the liner flange should be between 0.06 and 0.20 mm (.002 and .008 in) above the spacer plate. If this measurement is incorrect, remove the insert and remachine the counterbore.
NOTE: For additional details concerning the machining, installation tooling, and installation procedures, refer to Salvage And Reuse Guideline, SEBF8255, "Procedure To Install Top Deck Insert, 3500 Cylinder Block".