GMC Chevrolet Camaro 1998 Service Manual page 94

0-82 Vibration 'Diagnosis and· Correction
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General Information
2. Ensure that the front bearing cap (1) is also
vertical.
3. Place the inclinometer on the propeller shaft rear
U-joint bearing cap in order to ensure that both (
U-joints are vertical.
4. Set the indicator line above the sight glass on 15
(the horizontal reference) and rotate the propeller
shaft until the bubble centers in the sight glass.
This brings the rear U-joint to vertical.
5. Remove the inclinometer without disturbing the
setting. Leave the setting on 15 and install the
inclinometer on the front U-joint. The bubble
should remain centered plus or minus 3 degrees if
the shaft is properly phased.
The out of phasing of the single-piece propeller shaft
is very unusual. If the shaft is visibly out of place, the
end yokes are welded on in the wrong position, or
the shaft is damaged due to twisting. In either case,
replace the propeller shaft before continuing with
this procedure.
Measuring the Working Angles
The working angle of a U-joint is the difference
between the angles formed when two shafts intersect.
One piece propeller shaft systems have two· working
angles, .the front and the rear.
• The two working angles should be equal within 1 /2
of a degree:
• The working angles themselves should not
exceed 4 degrees.
• The working angles themselves should not be
equal to zero because a zero working angle
will cause premature U-joint wear due to lack of
rotation of the U-joints.
The angle of the propeller shaft and the rear axle
pinion form the rear working angle (2). The angle of
the propeller shaft and the transmission output
shaft form the front working angle (1 ).
The angles of these components are most accurately
measured from the U-joint bearing caps. The
bearing caps should be free of corrosion or foreign
material to ensure accurate readings. Remove
any snap rings that may interfere wit the correct
placement of the inclinometer. Do not forget to reinstall
them after you take the measurements .
Take the measurements from the same side of the
propeller shaft to maintain consistent angle
measurements (either driver or passenger side).
(