Miata 1990-1997

Accessory Drive Belts

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Adjustment



Specific to:

Mazda Miata 1990-1997



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Fig. Typical alternator mounting and drive belt adjustment points



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Fig. Typical power steering and air conditioning compressor mounting and drive belt adjustment points



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Fig. Single accessory drive belt adjustment points with idler pulley



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Fig. Measure the belt deflection between 2 pulleys along the longest span

Air Conditioning Belt

Specific to:

Mazda Miata 1990-1997

  1. Position a ruler perpendicular to the drive belt midway between the pulleys on the longest accessible belt span. Press firmly on the belt with your thumb to test the belt tension. The belt should deflect 0.31-0.35 in. (8-9mm) if it is new or 0.35-0.39 in. (9-10mm) if it is used.
  2.  
  3. If the belt tension is not as specified in Step 1, loosen the upper and lower air conditioning compressor through bolts.
  4.  
  5. Using a suitable prybar against the compressor body, move the compressor until the belt tension is as specified in Step 1.
  6.  
  7. After adjustment, tighten the upper and lower air conditioning compressor through bolts.
  8.  

Air Conditioning Compressor & Power Steering Pump

Specific to:

Mazda Miata 1990-1997

  1. Position a ruler perpendicular to the drive belt midway between the pulleys on the longest accessible belt span. Press firmly on the belt with your thumb to test the belt tension. The belt should deflect 0.31-0.35 in. (8-9mm) if it is new or 0.35-0.39 in. (9-10mm) if it is used.
  2.  
  3. If the belt tension is not as specified in Step 1, loosen the upper and lower air conditioning compressor through bolts.
  4.  
  5. Using a suitable prybar against the compressor body, move the compressor until the belt tension is as specified in Step 1.
  6.  
  7. After adjustment, tighten the upper and lower air conditioning compressor through bolts.
  8.  

Alternator Belt

Specific to:

Mazda Miata 1990-1997

  1. Position a ruler perpendicular to the drive belt midway between the pulleys on the longest accessible belt span. Press firmly on the belt with your thumb to test the belt tension. The belt should deflect 0.31-0.35 in. (8-9mm) if it is new or 0.35-0.39 in. (9-10mm) for a used belt.
  2.  
  3. If the belt tension is not as specified in Step 1, loosen the alternator adjustment bolt and the through bolt. Turn the alternator adjustment screw to adjust the belt tension.
  4.  
  5. After adjustment, tighten the through bolt to 27-38 ft. lbs. (37-52 Nm) and the adjusting bolt to 14-19 ft. lbs. (19-25 Nm).
  6.  

Inspection



Specific to:

Mazda Miata 1990-1997

Inspect the belts for signs of glazing or cracking. A glazed belt will be perfectly smooth from slippage, while a good belt will have a slight texture of fabric visible. Cracks will usually start at the inner edge of the belt and run outward. All worn or damaged drive belts should be replaced immediately. It is best to replace all drive belts at one time, as a preventive maintenance measure, during this service operation.

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Fig. There are typically 3 types of accessory drive belts found on vehicles today



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Fig. An example of a healthy drive belt



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Fig. Deep cracks in this belt will cause flex, building up heat that will eventually lead to belt failure



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Fig. The cover of this belt is worn, exposing the critical reinforcing cords to excessive wear



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Fig. Installing too wide a belt can result in serious belt wear and/or breakage

Removal & Installation



Specific to:

Mazda Miata 1990-1997


NOTE
When removing a belt from the engine, pay attention to its routing (over and under pulleys, etc.) before removing it. Drawing a quick picture may also help.

Follow the adjustment procedure to loosen the accessory drive belt. Once loose, simply remove the belt from the pulleys. If there is a belt in front of the one you need to remove, follow the adjustment procedures for that accessory as well.

A/C Compressor Belt

Specific to:

Mazda Miata 1990-1997

  1. Turn the ignition OFF and remove the key. Allow the engine to cool.
  2.  
  3. Remove the power steering pump belt and alternator belt, if necessary.
  4.  
  5. Loosen the tensioner bracket adjusting bolt and tensioner pulley center locknut to release the drive belt tension.
  6.  
  7. Remove the air conditioning belt.

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    Fig. Loosen the air conditioning compressor belt idler pulley lockbolt using an open end wrench



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    Fig. Loosen the air conditioning compressor belt idler pulley adjusting bolt just enough to be able to remove the belt



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    Fig. Remove the air conditioning compressor belt

  8.  

To install:

  1. Install the air conditioning belt, and make sure it is correctly seated on the pulleys.
  2.  
  3. Adjust the air conditioning belt tension/deflection by turning the tensioner bracket adjusting bolt. A new belt should deflect 0.33-0.39 in. (8.5-10mm), and a used belt should deflect 0.39-0.45 in. (10-11.5mm).
  4.  
  5. Tighten the tensioner pulley center locknut to 27-38 ft. lbs. (37-52 Nm).
  6.  
  7. Install and tension the alternator belt, if necessary, and the power steering pump belt.
  8.  
  9. Run the engine for 5 minutes and then recheck the belt deflection.
  10.  

Alternator Belt

Specific to:

Mazda Miata 1990-1997

  1. Turn the ignition OFF and remove the key. Allow the engine to cool.
  2.  
  3. Remove the power steering pump belt and air conditioning compressor belt, if necessary.
  4.  
  5. Loosen the alternator upper bracket adjusting bolt.
  6.  
  7. Loosen the lower through-bolt.
  8.  
  9. Remove the alternator belt.

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    Fig. To access the alternator pivot bolt, you must first remove the power steering pump pulley



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    Fig. Loosen the alternator pivot bolt located just below the alternator assembly



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    Fig. Loosen the alternator adjuster lockbolt (A), then turn the adjustment nut (B) to loosen the slack on the belt..



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    Fig. .. then remove the alternator belt

  10.  

To install:

  1. Install the alternator belt and make sure it is correctly seated on the pulleys.
  2.  
  3. Turn the adjusting bolt to adjust the belt deflection. New belts should deflect 0.39-0.47 in. (10-12mm). Used belts should deflect 0.43-0.51 in. (11-13mm).
  4.  
  5. Once the correct deflection has been reached, tighten the upper bracket lock bolt to 14-19 ft. lbs. (19-25 Nm).
  6.  
  7. Tighten the lower through-bolt to 28-38 ft. lbs. (38-51 Nm).
  8.  
  9. Install and tension the power steering pump belt and air conditioning compressor belt, if necessary.
  10.  
  11. Run the engine for 5 minutes and then recheck the belt deflection.
  12.  

Power Steering Pump Belt

Specific to:

Mazda Miata 1990-1997

  1. Turn the ignition OFF and remove the key. Allow the engine to cool.
  2.  
  3. Loosen the idler pulley locknut to release the drive belt tension.
  4.  
  5. Remove the power steering belt.

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    Fig. Using a box wrench, loosen the power steering pump belt idler pulley lockbolt



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    Fig. Loosen the power steering pump belt by turning the idler pulley adjusting bolt



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    Fig. Remove the power steering pump belt

  6.  

To install:

  1. Install the power steering belt and make sure it is correctly seated on the pulleys.
  2.  
  3. Adjust the power steering belt tension/deflection by turning the adjusting bolt. A new belt should deflect 0.26-0.28 in. (6.6-7.2mm) and a used belt should deflect 0.28-0.31 in. (7-8mm).
  4.  
  5. Tighten the idler pulley locknut to 27-38 ft. lbs. (37-52 Nm).
  6.  
  7. Run the engine for 5 minutes and then recheck the belt deflection.
  8.  

 
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