Loosen the capscrews which secure the fan hub shaft to the bracket.

NOTE: Both two capscrew and four capscrew designs are available.

Turn the adjusting screw counterclockwise to release tension, and remove the belts.

Inspect the pulleys for cracks or broken grooves. Replace if damage is found.

Inspect the belts for cracks, glazing, and tears or cuts.

Replace the belt set if one or more of the belts are damaged.

Inspect the pulley alignment. Pulley misalignment must not exceed 0.5 mm per cm [0.0625 in per foot] of distance between the pulley centers. Inspect, repair, or replace the fan hub or the fan hub support bracket if pulley misalignment exceeds 0.5 mm per cm [0.0625 in per foot]. Refer to Procedure 008-036 in Section 8.

Install new belts onto the pulley. When a drive pulley uses two or more belts, replace the belts as a complete set.

NOTE: To prevent damage, do not roll a belt over the pulley or pry it on with a tool.

Turn the adjusting screw to increase the belt tension.

NOTE: Belt tension can increase when the fan hub mounting capscrews are tightened. Do not adjust the belt tension to full value with the adjusting screw.

Tighten the capscrews until the fan hub is in correct alignment with the fan hub bracket.

NOTE: Do not tighten the capscrews to full torque value.

Measure the belt tension.

Refer to the Belt Tension Chart shown in Section V to select the correct gauge and tension values for the belt width.

A belt is considered used if it has been in operation for at least 10 minutes.

Tighten the fan hub mounting capscrews.

Measure the belt tension again using belt tension gauge, Part Number ST-1138, and adjust if necessary.

When satisfactory belt tension is obtained, loosen the adjusting screw 1/2-turn to prevent breakage.