disengaged. Do this with the engine idling since the noise is likely to be most apparent
at this time.
To begin with, when you have the clutch disengaged, you may discover that the noise
coming from the clutch is due to lack of lubrication or to defects in the assembly. For
instance, a dry or binding release bearing is likely to squeal when it is placed in
operation. If it does, you will usually need to replace the bearing. On some vehicles,
however, provisions are made for lubricating this bearing. If so, you can generally
lubricate or replace the bearing without removing the clutch assembly. Still, you may
need to remove the transmission and the lower cover from the flywheel housing to get
to the bearing. It usually pays for you to go a little further and inspect the entire clutch
assembly if you must remove the transmission for any reason.
Noise may also come from a worn or dry pilot bearing. Such a bearing tends to "whine"
when it is out of grease. This noise usually occurs when the vehicle is stationary with
the engine running, the transmission in gear, and the clutch disengaged. To remedy
this, replace the bearing and make sure it is properly lubricated if it is not a prepacked
bearing.
Other clutch noises may occur when you have the clutch disengaged. Any one of
several conditions can be responsible for noisy operation. For example, the clutch disc
may be loose on the transmission shaft (disc hub loose on shaft splines). If this is the
case, depending on the amount of wear, you may have to replace the input shaft and
the clutch disc. Another condition involving noise and necessitating disc replacement is
loose or weak torsional springs surrounding the disc hub. You may also find that the
antirattle springs on the pressure plate assembly are weak and require replacement. A
hose or misaligned transmission will cause noisy clutch operation. You can easily
correct this by loosening the transmission, shifting it into proper alignment, and
retightening it.
1.1.5 Clutch Pedal Pulsation
Movement felt on the clutch pedal or operating lever when the clutch is being
disengaged is called clutch pedal pulsation. These pulsations are noticeable when
slight pressure is applied to the clutch pedal. This is an indication of trouble that could
result in serious damage if not immediately corrected. Several conditions could cause
these pulsations.
One condition that can cause this vibration is misalignment of the engine and
transmission.If the engine and transmission are not in line, detach the transmission and
remove the clutch assembly. Check the clutch housing alignment with the engine and
crankshaft. At the same time, check the flywheel for wobble. A bent crankshaft flange or
an improperly seated flywheel produces clutch pedal pulsations. After the flywheel is
properly seated, check it using a dial indicator. If the crankshaft flange is bent, the
crankshaft must be remachined or replaced
.
Other causes of clutch pedal pulsations include uneven release lever adjustments, a
warped pressure plate, or a warped clutch disc. If the clutch disc or pressure plate is
warped, it should be replaced.
It would be impractical to list every possible clutch problem and its remedy for repair in
this training manual. Consult the manufacturer's operation and repair manual before
making adjustments to any clutch system
.
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