10-66. BODY REPAIR
This task covers:
c. Rivet Replacement
General mechanics tool kit
Sealing compound (Appendix C, Item 40)
automotive (Appendix B, Item 1)
Tool kit, riveter (Appendix B, Item 139)
The M998 series body is constructed from aluminum alloys that have been heat treated to obtain
high strength. Welding cannot be used to make body repairs. Heat generated in welding will reverse
the heat treatment process and cause a great reduction in strength of material.
Solid 3/16 inch diameter aluminum rivets are the primary method of joining body components.
Rivets are inserted into a hole through two pieces of metal and a second head is formed by manual
or pneumatic impacting. or by squeezing the rivet. A bucking bar is used to backup the rivet to form
rivet head. When making repairs, use blind rivets of the same size or oversize diameter with the
appropriate grip length.
Blind structural aluminum rivets of 3/16 inch diameter are used in applications where there is
access from only one side of the part. Blind rivets are installed using a tool that pulls on the rivet
stem causing a bulbed head to form on the back side of the part. Fastening is complete when stem
breaks off. High strength is obtained in blind structural rivets by mechanically locking the
remaining stem inside rivet body. Blind pop rivets are used in locations where non-structural
attachments such as latches, striker plates, etc., are attached to the body.
Steel pull-type lockbolt fasteners in 3/16 and 1/4-inch diameter are used where tension or high shear
loads exist. Lockbolts are two-piece unthreaded fasteners. One part is a high-strength, steel-headed
bolt-like part with aberrations on its shank. The mating part is a collar which is swaged over the
serrations causing the fastener to be locked in place.
Rivnut/plusnut fasteners are tubular rivets with internal threads. Rivnut/plusnut fasteners are
installed using a tool that engages the threads of the fastener and extends a pull, causing the shank
to expand tightly against the material being fastened. This process is called upsetting a
Rivet and Lockbolt replacement.
To facilitate repairs to body, it is acceptable to replace lockbolts and rivets with 1/4 inch AN4 series
bolts. Do not replace lockbolts with rivets. Standard threaded fasteners should not be used, as these
will quickly wear the aluminum structure. Bolt lengths should be chosen so that the cylindrical
portion of bolt is bearing on all members being joined. Bolts are designated as AN4-XX or AN4C-XX
where XX defines grip length. Tighten all bolts to 70-75 lb-in. (8-9 N.m).
Fatigue strength of riveted joints and seams is increased by one part epoxy adhesive. This adhesive
requires special material storage and metal preparation along with a low temperature heat cycle for
curing. Because of its impracticality in field repairs, epoxy adhesive will not be used. Where
possible, extra rivets and thicker metal gages should be used instead of adhesives. When making
repairs, note epoxy exists and that parts may be difficult to separate, even after rivets are removed.