M977, M985, and M984E1 Crane Maintenance Instructions (Cont)
17-33. OVERLOAD SENSOR SWITCH ADJUSTMENT (CONT).
M985 and M977 Overload Sensor Switch Adjustment.
Measure the distance between the end of screw (1) and the face of nut (2). If measurement is
0.062 in. (1.58 mm), go to step (3). If measurement is not 0.062 in. (1.58 mm), go to step (2).
Loosen nut (2) and adjust screw (1) with nut (3) to get a measurement of 0.062 in. (1.58 mm).
Tighten nut (2).
Be sure proper weight is used to adjust M985 or M977 crane, or equipment may be
M985 has one overload sensor switch. M977 has two overload sensor switches.
For M977 main overload sensor switch (A) adjustment, position boom at maximum
boom angle before weight is attached.
For M977 reduced overload sensor switch (B) adjustment, boom must be 10° above
For M977 main and reduced overload sensor switch adjustments, extend boom so that
cable is spooling onto right side of drum, looking from boom nose.
For M985 overload sensor switch adjustment, extend boom so that cable is spooling
onto left side of drum, looking from boom nose.
Position load hook (4) over weight and attach weight.