PUMP GP-TRANSMISSION GEAR 3P4405 - Caterpillar

ENGINES
3406B AND 3406C ENGINESProblem:
Reports of early hour oil consumption and slobber may sometimes be attributed to excessive valve guide wear. This wear is generally isolated to the exhaust valve guides only.Solution:
The worn valve guides can be replaced without removing the cylinder head. This maintains the integrity of the head to block seal. Existing service tools can be modified to do this task. See TOOL MODIFICATION and REPLACEMENT PROCEDURE.Tool Modification:
Modify the Plate Assembly (part of the 1U9347 Valve Spring Compressor Group) as shown in Illustration 1. The Plate Assembly is used to compress all four valve springs for a cylinder at once. The modification will provide clearance with the rocker arm stands. This will allow the valve guides closest to the exhaust manifold "outboard guides" to be replaced without draining the coolant or removing the rocker arm shaft assembly.Modify the 1U95725/8Inch Extractor (part of the 1U9570 Dowel Puller Group) as shown in Illustration 2. The inside diameter of the slotted end of the extractor must be enlarger to a diameter of 17.53 to 17.63 mm (.690 to .694 in). This diameter should be maintained to the end of the slots or 38 mm (1.5 in). The larger diameter will allow the extractor to fit over the valve guide.Modify the 1U9577 Forcing Collar (part of the 1U9570 Dowel Puller Group) as shown in Illustration 3. The outside diameter of the collar must be reduced to 46 mm (1.8 in) for a length of 57.0 mm (2.25 in). Do not modify the end of the collar with the "knurl". This modification will provide clearance between the outside of the forcing collar and the cylinder head bridge dowel and the fuel injector nozzle adapter in the cylinder head.Modify the 7S8859 Driver as shown in Illustration 4. The length of the bore guide pilot is shortened to 13 mm (.5 in). This will prevent the driver pilot from contacting the end of the valve when installing the guide in the cylinder head.Replacement Procedure:
1.Remove the valve cover, base, and related components. See the appropriate Service Manual Disassembly and Assembly module.2.If the engine is eguipped with a compression brake, remove the compression brake.3.Remove the rocker shaft assemblies and bridges.4.Turn the crankshaft until the pistons of the No.1 and No. 6, or No. 3 and No. 4, or No. 2 and No. 5 are at the top of the cylinder. Two cylinders may be worked on at each position. When the pistons are at the top of their travel, they can support the valves as the valve stem keepers are removed.5.The modified plate assembly (part of the 1U9347 Valve Spring Compressor Group) can be used without removing the rocker arm stands. Special Instruction, SEHS9032, "Using 1U9347 Valve Spring Compressor Group" is included with the tooling. Use the valve spring compressor group to remove the valve keepers, rotocoil assemblies, springs, and guide washers.6.Inspect the area for debris on top of the valve guide and excessive side to side movement of the valve stem in the valve guide.