Manual Belt Tensioner Adjustment

RG10556-UN-21DEC99

Check Belt Tension

RG10557-UN-21DEC99

Adjust Belt Tension

A - Belt Tension Gauge

B - Cap Screw

C - Cap Screw

D - Tensioner Bracket

NOTE: Two types of manual tensioners shown.

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. NOTE: If timing gear cover or alternator bracket interfere with installation/centering of belt tension gauge (A), install gauge with face toward engine.

   Install JDG1341 Belt Tension Gauge (A) on belt, halfway between pulleys as shown. (JDG1341 Belt Tension Gauge available from local John Deere Dealer or Distributor.)

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2. Loosen cap screws (B) and (C).

3. Slide alternator or tensioner bracket (D) in slot by hand to remove all excess slack in belt.

4. IMPORTANT: Do not pry against alternator rear frame.

   Stretch belt by prying outward on alternator front frame or tensioner bracket. Observing tension gauge, stretch the belt until specified tension is achieved.

   Item	Measurement	Specification
   New Belt	Tension	470—650 N (105—145 lb-force)
   Used Belt	Tension	400—580 N (90—130 lb-force)

5. Tighten cap screws (B) and (C).

6. NOTE: After ten minutes run-in, new belts are considered used. Belt tension must then be rechecked per used belt specifications.

   Run engine for ten minutes and immediately re-check belt tension per used belt specification above.

7. Reset belt tension as necessary.