Chrysler Full-Size Trucks 1967-1988 Repair Guide

Belts

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See Figures 1 and 2

INSPECTION



Once a year or at 12,000 mile (19,000 km) intervals, the tension (and condition) of the alternator, power steering, air conditioning, and Thermactor air pump drive belts (as equipped) should be checked. If necessary, the belts should be replaced or adjusted. Loose accessory drive belts can lead to poor engine cooling and diminish alternator, power steering pump, air conditioning compressor or air pump output. A belt that is too tight places a severe strain on the components it is driving which will lead to early component failure.

Replace any belt that is so glazed, worn or stretched that it cannot be tightened sufficiently. There are two different types of belts that may be found on your truck, v-belts (single ribbed) and serpentine type (multi-ribbed). Both of these types may drive one or more accessories.



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Fig. Fig. 1: Common types of belts



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Fig. Fig. 2: When removing a belt, always inspect for wear or damage

The material used in late model drive belts is such that the belts do not show wear as readily. Replace belts at least every three years.

On vehicles with matched belts, replace both belts. New 1 / 2 , 3 / 8 and 1 /5 33 in. wide belts are to be adjusted to a tension of 140 lbs. and 1 / 4 in. wide belts are adjusted to 7 lbs. (as measured on a belt tension gauge). Any belt that has been operating for a minimum of 10 minutes is considered a used belt. In the first 10 minutes, the belt should stretch to its maximum extent. After 10 minutes, stop the engine and recheck the belt tension. Belt tension for a used belt should be maintained at 110 lbs. for all except 1 / 4 in. wide belts or at 60 lbs. for 1 / 4 in. wide belts. If a belt tension gauge is not available, the following procedures may be used.

ADJUSTMENTS



See Figures 3 through 8


CAUTION
If equipped, the electrically operated cooling fan may come on under certain circumstances, even though the ignition is OFF. Be sure to disconnect the negative battery cable before servicing your vehicle.



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Fig. Fig. 3: Belt routing-225 engine



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Fig. Fig. 4: 318 and 360 engines



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Fig. Fig. 5: 360 engine belt routing for trucks over 8500 lbs. GVW

Alternator Belt
  1. Position a ruler perpendicular to the drive belt at its longest straight run. Test the tightness of the belt by pressing it firmly with your thumb. The deflection should be between 1 / 4 - 5 / 16 in. (6-8mm).
  2.  
  3. If the deflection exceeds these limits, loosen the alternator mounting and adjusting arm bolts.
  4.  
  5. Place a 1 in. (25mm) open-end or adjustable wrench on the adjusting ridge cast on the body, and pull on the wrench until the proper tension is achieved.
  6.  
  7. Holding the alternator in place to maintain tension, tighten the adjusting arm bolt. Recheck the belt tension. When the belt is properly tensioned, tighten the alternator mounting bolt.
  8.  



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Fig. Fig. 6: Checking for proper belt tension



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Fig. Fig. 7: To adjust tension, first loosen the adjusting bolt



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Fig. Fig. 8: Then move the component or idler pulley in the bracket to obtain the proper tension and hold it while you tighten the bolt

Power Steering
INLINE 6-CYLINDER ENGINES
  1. Hold a ruler perpendicular to the drive belt at its longest run, test the tightness of the belt by pressing it firmly with your thumb. The deflection should be within 1 / 4 in. (6mm), and 5 / 16 in. (8mm).
  2.  
  3. To adjust the belt tension, loosen the adjusting and mounting bolts on the front face of the steering pump cover plate (hub side).
  4.  
  5. Using a large wooden dowel or a pry bar wrapped with a rag to protect the pump hub from damage, carefully pry on the hub in order to move the power steering pump toward or away from the engine until the proper tension is reached. Do not pry against the reservoir as it is relatively soft and easily deformed.
  6.  
  7. Holding the pump in place, tighten the adjusting arm bolt and then recheck the belt tension. When the belt is properly tensioned tighten the mounting bolts.
  8.  

6-CYLINDER AND V8 ENGINES
  1. Position a ruler perpendicular to the drive belt at its longest run. Test the tightness of the belt by pressing it firmly with your thumb. The deflection should be between 1 / 4 - 5 / 16 in. (6-8mm).
  2.  
  3. To adjust the belt tension, loosen the three bolts in the three elongated adjusting slots at the power steering pump attaching bracket.
  4.  
  5. Turn the steering pump drive belt adjusting nut as required until the proper deflection is obtained. Turning the adjusting nut clockwise will increase tension and decrease deflection; counterclockwise will decrease tension and increase deflection.
  6.  
  7. Without disturbing the pump, tighten the three attaching bolts.
  8.  

Air Conditioning Compressor
  1. Position a ruler perpendicular to the drive belt at its longest run. Test the tightness of the belt by pressing it firmly with your thumb. The deflection should be between 1 / 4 - 5 / 16 in. (6-8mm).
  2.  
  3. If the engine is equipped with an idler pulley, loosen the idler pulley adjusting bolt, insert a pry bar wrapped with a rag, between the pulley and the engine (or in the idler pulley adjusting slot), and adjust the tension accordingly. If the engine is not equipped with an idler pulley, the alternator must be moved to accomplish this adjustment, as outlined under Alternator Belt.
  4.  
  5. When the proper tension is reached, tighten the idler pulley adjusting bolt or the alternator adjusting and mounting bolts, as equipped.
  6.  

Air Pump
  1. Position a ruler perpendicular to the drive belt at its longest run. Test the tightness of the belt by pressing it firmly with your thumb. The deflection should be between 1 / 4 - 5 / 16 in. (6-8mm).
  2.  
  3. To adjust the belt tension, loosen the adjusting arm bolt slightly. If necessary, also loosen the mounting belt slightly.
  4.  
  5. Using a large wooden dowel or a pry bar wrapped with a rag to protect the pump from damage, carefully pry against the pump rear cover to move the pump toward or away from the engine as necessary.
  6.  


CAUTION
Do not pry against the pump housing itself, as damage to the housing may result.

  1. Holding the pump in place, tighten the adjusting arm bolt and recheck the tension. When the belt is properly tensioned, tighten the mounting bolt.
  2.  


WARNING
Check to make sure that the V-ribbed belt is located properly in all drive pulleys before applying tensioner pressure.

REMOVAL & INSTALLATION



See Figure 9

On most vehicles, to remove and install a new belt, you will need to loosen the mounting bracket bolts of the component. Using a suitable pry tool wrapped with a towel or rag, carefully pry the component forward slightly to give easy access to slide the belt off and on. You may need to do this an additional component(s) in order to make removal or installation easier. Some models have a few belts running different accessories, if you must replace a belt in the rear, you will first have to remove the belt(s) that are in your way. Look at your truck first to decide how many belts require removal to access the belt in need of replacement.



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Fig. Fig. 9: Serpentine belt mounting

 
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