Engine: Pull the dipstick and run oil through
your fingers to check for grit. If the oil has a milky appearance, the
machine likely has a bad head gasket that has leaked antifreeze.
Turntable: Use a flashlight to check for leaks
and loose bolts behind the main valve bank, where the gearbox meets the
turntable bearing. Carefully study the turntable bearing’s teeth for any
signs of bending or breakage. Test swing box wear by shifting the boom
from side-to-side. Any movement beyond 1.5 inches is excessive – the
result of broken gears or turntable slack.
Hydraulics: Hydraulic leaks are the major concern
on the chassis. Note any leaks on the drive motors, caused by
loose-fitting or blown oil rings and indicative of impact damage. Also
inspect the steering linkage and its hoses for any signs of leaks.
Power Track: While the machine is running, extend
the power track until cables and hoses from the upper control box are
fully extended. This will expose any hydraulic hose leaks or broken links.
Boom: Use a flashlight to spot leaks within the
boom structure. If you find any paint cracks, check the boom for a bent
appearance. Paint cracks and visible bends are both the result of basket
overload. With one hand on the basket, bounce it up and down feeling for
side-to-side movement. This will reveal the condition of the wear pads,
located at the front of each telescoping section.