REPAIR COMMANDERS CUPOLA BEARING (M113A3, M1059A3, M1064A3, AND M58
Improper installation will cause binding, resulting in bearing failure. Bearing block (7) concave
surface must face toward cupola center.
Do not use talcum or other powder to reduce friction. When talcum is exposed to moisture, a
chalky substance will form, causing binding.
Alternately, install 24 separators (6) and 23 ball bearings (5) between bearing blocks (7). One
separator (6) is to be installed on each side of each bearing block (7). A maximum number of
sets (one ball and one spacer per set) is needed between any two blocks. The number of sets in
each space between blocks must not differ by more than one set.
Install 140 ball bearings (5), 146 separators (6), and 6 bearing blocks (7) in groove of inner race (8).
The outer race and inner race must be aligned correctly so that the traverse lock pin will fit.
Install outer race (3) on hatch (4). Place large unthreaded hole in outer race (3) directly above largest unthreaded hole in
inner race (8).