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For frozen screws, apply penetrating fluid as
described, the insert a screwdriver in the slot and
rap the top of the screwdriver with a hammer. This
loosens the rust so the screw can be removed in the
normal way. If the screw head is too damaged to
use this method, grip the head with locking pliers
and twist the screw out.
Avoid
applying
instructed. Heat may melt, warp or remove the
temper from parts.
Removing Broken Fasteners
If the head breaks off a screw or bolt, several
methods are available for removing the remaining
portion. If a large portion of the remainder projects
out, try gripping it with locking pliers. If the projecting
portion is too small, file it to fit a wrench of cut a slot
in it to fit a screwdriver (Figure 37)
If the head breaks off flush, use a screw
extractor. To do this, center punch the exact center
of the remaining portion of the screw or bolt. Drill a
small hole in the screw and tap the extractor into the hole. Back the screw out with a wrench on the
extractor (Figure 38)
Repairing Damaged Threads
Occasionally, threads are stripped through
carelessness or impact damage. Often the threads
can be repaired by running a tap (for internal
threads on nuts) or die (for external threads on bolts)
through the threads (Figure 39). To clean or repair
spark plug threads, use a spark plug tap.
If an internal thread is damaged, it may be
necessary to install a Helical or some other type of
thread insert. Follow the manufacturer's instructions
when installing their insert.
If it is necessary to drill and tap a hole, refer to Table 8 for metric tap and drill sizes.
Stud Removal/Installation
A stud removal tool (Figure 40) is available from most tool suppliers. This tool makes the removal
and installation of studs easier. If one is not available, thread two must onto the stud and tighten them
GENERAL INFORMATION
heat
unless
specifically
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Table of Contents
Troubleshooting
