SHAFT ASSEM. 6N4441 - Caterpillar

Cylinder Leakage - Test
Introduction
A leakage test may be performed to measure cylinder/combustion chamber leakage. High cylinder leakage may indicate one or more of the following:
Worn or burnt valves
Broken valve springs
Stuck valve lifters
Incorrect valve lash
Damaged piston
Worn piston rings
Worn or scored piston bore
Damaged cylinder head gasket
Cracked or damaged cylinder head
Cracked or damaged engine blockTest Procedure
Disconnect the battery ground negative cable.
Remove the spark plugs.
Rotate the crankshaft to place the piston in the cylinder being tested at Top Dead Center (TDC) of the compression stroke.
Install the Cylinder leak down tester.
Apply shop air pressure to the leak down tester and adjust according to the manufacturer instructions.
Record the cylinder leakage value. Cylinder leakage that exceeds 25 percent is considered excessive and may require component service. In excessive leakage situations, inspect for the following conditions:
Air leakage sounds at the throttle body or air inlet hose that may indicate a worn or burnt intake valve or a broken valve spring.
Air leakage sounds at the exhaust system tailpipe that may indicate a worn or burnt exhaust valve or a broken valve spring.
Air leakage sounds from the crankcase, oil level indicator tube, or oil fill tube that may indicate worn piston rings, a damaged piston, a worn or scored cylinder bore, a damaged engine block or a damaged cylinder head.
Air bubbles in the cooling system may indicate a damaged cylinder head or a damaged cylinder head gasket.
Perform the leakage test on the remaining cylinders and record the values.Engine Mount - Inspect
Introduction
Broken or deteriorated mounts can cause misalignment and destruction of certain drive train components. When a single mount breaks, the remaining mounts are subjected to abnormally high stresses.
When raising or supporting the engine for any reason, do not use a jack under the oil pan, any sheet metal, or the crankshaft pulley. Due to the small clearance between the oil pan and the oil pump screen, jacking against the oil pan may cause the pan to be bent against the pump screen. This will result in a damaged oil pickup unit.
Test Procedure
Measure the engine movement at the engine mount to check for damage to the rubber portions of the mount.
Apply the parking brake.
Start the engine.
Firmly apply and hold the primary brakes.
Have someone stand to the side of the engine and observe the movement.
Slightly load the engine, shifting from drive to reverse a few times.
If the engine moves more than 24 mm (0.945 inch) from the rest position in either direction, check for loose engine mount bolts.
If the engine mount bolt torque is within specifications, check the condition of the engine mounts.
Replace the engine mounts if any of the following conditions is met:
Heat check cracks cover the rubber cushion surface.
The rubber cushion is separated from the metal plate of the mount.
There is a split through the rubber cushion.