Manual Belt Tensioner Adjustment Using Belt Tension Tool (Alternate Method For Engines Without Auxiliary Drive)

RG11812
RG11812-UN-31OCT01

Alternator Bracket and Cap Screws

RG11813
RG11813-UN-31OCT01

Belt Tension Tool

A - Upper Alternator Bracket Cap Screw

B - Lower Alternator Bracket Cap Screw

C - JDG1520 Belt Tension Tool

D - Belt

NOTE: The JD1520 Belt Tension Tool may not be compatible with all alternators. In that case, use the preceding method for belt tensioning.

NOTE: Inspect belts for cracks, fraying, or stretched-out areas. Replace if necessary.

As a reference check, twist belt in the middle of a 254—305 mm (10—12 in.) span with two fingers. A properly tensioned belt will turn 75—85 degrees. If belt turns more, it needs to be tightened. If belt turns less, it needs to be loosened.

  1. Loosen upper (A) and lower (B) alternator bracket cap screws. Lower cap screw must remain tight enough to prevent excessive alternator play but allow alternator to pivot by hand.

  2. Insert JDG1520 Belt Tension Tool (C) behind belt (D) and over alternator mounting screw.

  3. RG11814
    RG11814-UN-31OCT01

    Belt Tension Tool and Torque Wrench

    RG11815
    RG11815-UN-31OCT01

    Scribe Reference Mark

    A - Alternator

    B - Belt Tensioning Tool

    C - Torque Wrench

    D - Reference Mark

    E - Alternator Upper Bracket Notch

    Place torque wrench (C) on belt tensioning tool (B) at 90° to tool. Pivot alternator (A) until desired torque is achieved according to specification using the following table.

    ItemMeasurementSpecification
    New BeltTension470—650 N (105—145 lb-force)
    Used BeltTension400—580 N (90—130 lb-force)

    JDG1520 Belt Tensioning Tool Torque Table

    Desired Belt Tension N (lb-force)

    Applied Torque N˙m (lb-ft)

    445 (100)

    108 (90)

    489 (110)

    115 (85)

    534 (120)

    122 (90)

    623 (140)

    135 (100)


  4. While holding tension with torque wrench (B), scribe a reference mark (D) on alternator in line with notch (E) on upper alternator bracket.

  5. Continue to hold tension with torque wrench and tighten upper alternator bracket cap screw.

  6. Check position of reference mark to see if alternator moved while tightening. If alternator moved, loosen upper alternator bracket cap screw and repeat the tension adjustment procedure.

  7. Remove belt tension tool and tighten lower alternator bracket cap screw.

OUOD002,000016D-19-20060727