Checking Belt Tensioner Spring Tension

RG8742-UN-03SEP99

Upper Tensioner Shown, Lower Tensioner Similar

A - Swing Arm Cast Stops

B - Fixed Cast Stops

Visually inspect cast stops (A and B) on belt tensioner assembly.

If the tensioner swing arm stop (A) is hitting the fixed stop (B), check mounting brackets and the belt length. Replace belt as needed. (See Replacing Fan and Alternator Belts in the Service As Required Section.)

Checking Upper Tensioner Spring Tension

RG19639-UN-09NOV10

Marks on Tensioner

A - Mark on Swing Arm

B - Mark on Tensioner Mounting Base

NOTE: While belt is loosened, inspect pulleys and bearings. Rotate and feel for hard turning or any unusual sounds. If pulleys or bearings need replacement, see your John Deere dealer.

A belt tension gauge will not give an accurate measure of the belt tension when automatic spring tensioner is used. Measure tensioner spring tension using a torque wrench.

1. Release tension on belt using a long-handled 3/4-in. drive tool in square hole in end of tensioner arm. Remove belt from pulleys.

2. Release tension on tensioner arm and remove drive tool.

3. Put a mark (A) on swing arm of tensioner as shown.

4. Measure 25 mm (1.0 in.) from first mark (A) and put a second mark (B) on tensioner mounting base.

5. Rotate the swing arm using a torque wrench until marks (A and B) are aligned.

6. Record torque wrench measurement and compare with specification. Replace tensioner assembly as required.

   Item	Measurement	Specification
   Upper Spring Tension	Torque	81—99 N·m (60—73 lb.-ft.)

Checking Lower Tensioner Spring Tension

RG19640-UN-09NOV10

Marks on Tensioner

A - Mark on Swing Arm

B - Mark on Tensioner Mounting Base

A belt tension gauge will not give an accurate measure of the belt tension when automatic spring tensioner is used. Measure tensioner spring tension using a torque wrench.

1. Release tension on belt using a long-handled 1/2-in. drive tool in tensioner arm. Remove belt from pulleys.

2. Release tension on tensioner arm and remove drive tool.

3. Put a mark (A) on swing arm of tensioner as shown.

4. Measure 21 mm (0.83 in.) from first mark (A) and put a second mark (B) on tensioner mounting base.

5. Rotate the swing arm using a torque wrench until marks (A and B) are aligned.

6. Record torque wrench measurement and compare with specification. Replace tensioner assembly as required.

   Item	Measurement	Specification
   Lower Spring Tension	Torque	45—56 N·m (33—41 lb.-ft.)