BODY REPAIR (Contd)
The damaged area should be thoroughly cleaned and inspected to determine cause and extent of
damage. Body parts should be inspected for holes, cracks, dents, distortion, or breaks. Fasteners
should be inspected for breaks, stretching, looseness, cocked heads, or hole elongation. Seams,
flanges, and joints should be inspected for straightness or local deformation which is an indication
that fasteners may have been stretched or holes elongated. It is possible for this to happen and
fasteners can still appear to be tight in their holes. In addition, make thorough inspection of
adjacent areas to determine if high loads have been transmitted from the damaged area to other
areas. This can result in secondary damage of distorted panels or seams, loosened or sheared
fasteners, elongated fastener holes, and cracks.
Signs of rivet failure include tipped heads, looseness, and sometimes chipped or cracked paint. If
heads are tipped in the same direction and rivets are loose in consecutive groups, the joint has
undergone excessive load. Rivet heads which are tipped in different directions and are not in groups
may be improperly installed. With chipped or cracked paint, it may be necessary to remove paint to
check true condition of rivets. Rivets subjected to critical loads but showing no distortion should be
inspected if failure is suspected. The head should be drilled off, and the shank should be carefully
punched out. Failure is indicated by notched rivet shank and misaligned holes. Flush rivets showing
head slippage within the dimple or countersink indicate either sheet bearing or rivet shear failure
and must be removed for inspection and replacement. If failure of rivets cannot be detected by visual
inspection, the joint can be checked by drilling and punching out several rivets. If rivet shanks are
notched, rivets should be replaced with next larger size rivets. If rivet holes show elongation due to
local failure in tearing of the sheet, the next larger size rivet must be used in replacement. Any
deformation of the sheet around the rivet, tear-outs, or cracks between rivets usually indicates
partially failed or damaged rivets. Complete repairof the joint will require replacement by the next
larger size rivets. Use the next l/32-in. larger diameter rivet to obtain a tight joint when original
hole has been enlarged. If original size rivet is installed, the rivet will not be able to carry its share
of the shear load, and the joint would not meet its strength requirement.
c. Rivet Replacement
When removing rivets, do not enlarge rivet hole because this
would require use of an oversize or larger rivet for replacement.
Solid Rivet Removal.
File a flat surface on the manufactured head if accessible. It is always preferable to work on
manufactured head rather than the one that is bucked over, since the former will always be
more symmetrical around the shank.
Indent center of the filed surface with a center punch.
Drill through rivet head. Be sure to use a drill slightly smaller than diameter of rivet shank to
avoid making rivet hole oversized.
Shear weakened rivet head off with a sharp chisel. For this operation, support back side of rivet
and cut rivet head along direction of rivet line or panel edge. This will prevent distortion of the
Firmly support the panel from the opposite side and drive out shank with a pin punch. If rivet is
unduly tight because of swelling between sheets, drill rivet shank out with an undersize drill.
Blind Rivet Removal.
(a) File a small flat on rivet head.
(b) Center-punch the flat. Support rivet backside, if possible.
(c) Using a small drill about the size of rivet pin, drill off tapered end of pin which forms the lock.