CAUTION
Never use a sledge hammer directly on a yoke to separate a U-joint. The result will
almost certainly be a damaged driveshaft.
4.4.2 General U-Joint Removal Precautions
Do not distort the driveshaft tube by applying excessive clamping force. Using an
appropriate puller such as the one shown in
Figure 8-54
is the best way to remove
plate-type bearing caps. If a puller is not available or if the U-joint is not equipped with
bearing plates, you can use an arbor press or hammer and soft round drift to remove
the bearings.
Figure 8-54 - Plate-type bearings can be removed with a puller.
Another way to remove U-joints is to support the cross on vise jaws, and then tap the
yoke to drive the bearing cup forward. This is the least preferred method because of its
potential to damage either the yoke or the slip spline assembly. Use a minimum amount
of aggression. When the bearing cup can be pulled out by hand, reverse the yoke and
U-joint and repeat the procedure to remove the opposite bearing cap.
4.5.1 U-Joint Lubricating Analysis
Inspect the U-joints and bearing cups for signs of wear and damage.
•
Cracks are stress lines caused by metal fatigue. Severe and numerous cracks
will weaken the metal until it breaks.
•
Galling occurs when metal is cropped off or displaced because of friction
between surfaces. Galling is commonly found on trunnion ends.
•
Spalling (surface fatigue) occurs when chips, scales, or flakes of metal break off
due to fatigue rather than wear. Spalling is usually found on splines and U-joint
trunnion races.
NAVEDTRA 14050A
8-59