Bearing Clearance - Check
SMCS Code: 1203-535; 1219-535
Keep all parts clean from contaminants.
Contaminants may cause rapid wear and shortened
Caterpillar does not recommend the checking of
the actual bearing clearances particularly on
small engines. This is because of the possibility
of obtaining inaccurate results and the possibility
of damaging the bearing or the journal surfaces.
Each Caterpillar engine bearing is quality checked
for specific wall thickness.
NOTE: The measurements should be within specifications
and the correct bearings should be used. If the
crankshaft journals and the bores for the block
and the rods were measured during disassembly,
no further checks are necessary. However, if the
technician still wants to measure the bearing
clearances, Tool (A) is an acceptable method.
Tool (A) is less accurate on journals with small
diameters if clearances are less than 0.10 mm
Lead wire, shim stock or a dial bore gauge can damage
the bearing surfaces.
The technician must be very careful to use Tool (A)
correctly. The following points must be remembered:
Ensure that the backs of the bearings and the bores
am clean and dry.
Ensure that the bearing locking tabs am properly
seated in the tab grooves.
The crankshaft must be free of oil at the contact
points of Tool (A).
Put a piece of Tool (A) on the crown of the bearing
that is in the cap. Do not allow Tool (A) to extend
over the edge of the bearing.
Use the correct torque-turn specifications in order to
install the bearing cap. Do not use an impact wrench.
Be careful not to dislodge the bearing when the cap is
Do not turn the crankshaft when Tool (A) is installed.
Carefully remove the cap, but do not remove Tool (A).
Measure the width of Tool (A) while Tool (A) is in the
bearing cap or on the crankshaft journal. Refer to
Remove all of Tool (A) before you install the bearing
When Tool (A) is used, the readings can
sometimes be unclear For example, all parts of
Tool (A) are not the same width. Measure the
major width in order to ensure that the parts are
within the specification range.