My alternater belt tensioner get tight and won't spin freely when I tighten the bolt holding tensioner

you have to locate your tensioner get a tensioner tool or socket set lock it on the bolt andpush upward and make sure all alternator bolts are tight

Loosen the altenater and use a prying bar to tighten the belt by pushing the altnater so as to tighten the belt. while holding altenater in place tighten bolts back tight. Belt should be tight when finished.

Assuming that the belt is not broken ... you need to tighten the belt. This one is not as easy as the other two which have tensioners. This belt is tensioned by the alternator itself. I've found adjusting it to not be a lot of fun ... the tricky part is loosening the bolt that the alternator pivots on. There isn't a lot of room and I find one of the small palm ratchets to be helpful. So to tighten, you'd loosen the upper bolt that actually holds the tension on the belt, loosen the bolt that the alternator pivots on, re-tension the belt (using something to pry on the alternator if necessary) and tighten the two bolts again. If you have to replace the belt you'll need to remove the outer two to get to this one. The outer two tensioners are adjusted by loosening the bolt that holds the tensioner pulley in place and then turning the tensioner bolt itself to tighten or loosen the belt(s)... then retighten the bolt holding the pulley.

The belt tensioner keeps the belt tight inside each accessory pulley while the engine is running. The tensioner is made up of a spring-loaded arm. If the spring inside of the tensioner becomes loose then it will not be able to hold the belt properly.And belt will also get loose. The belt tensioner is on the engine underneath the alternator. Its fitted by bolt.To loose the belt you will need drive socket and breaker bar .Turn the breaker bar counterclockwise to release tension from the belt.Remove the mounting bolt at the top center of the tensioner arm.The tensioner arm is loose and will easily come out.If you in-case are to replace the tensioner then place the new tensioner in same place and tighten the bolt which you removed.Before removing or moving the belt check the position of the belt passing from each pulley.so that when you fit the parts there is no problem in fitting the parts.
After its done.Start the engine and see that belt and tensioner runs freely and belt moving from each pulley smoothly. ------------- This will help.Thanks.Helpmech.

V-BELT ADJUSTMENT CAUTION
On models equipped with an electric cooling fan, disconnect the negative battery cable or fan motor wiring harness connector before replacing or adjusting drive belts. The fan may come on, under certain circumstances, even though the ignition is OFF. Alternator Drive Belt

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 not exceed 1?4 in. (6mm).
2. If the deflection exceeds 1?4 in. (6mm), loosen the alternator mounting and adjusting arm bolts.
3. On 1968-72 V8 and 6 cylinder models, use a prytool to move the alternator toward or away from the engine until the proper tension is reached. NOTE: Apply tension to the front of the alternator only. Positioning the prytool against the rear end housing will damage the alternator.
   
4. On 1973 and later V8 models, place a 1 in. (25.4mm) open-end or equivalent wrench on the adjusting arm bolt and pull on the wrench until the proper tension is achieved.
5. Holding the alternator in place, tighten the adjusting arm bolt. Inspect the belt tension. When the belt is properly tensioned, tighten the alternator mounting bolt. Fig. 1: Alternator belt adjustment
   

Power Steering Drive Belt ALL 6-CYLINDER AND 1971-72 V8 MODELS

1. Holding 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 not exceed 1?4 in. (6mm).
2. To adjust the belt tension, loosen the adjusting and mounting bolts on the front face of the steering pump cover plate (hub side).
3. Using a prytool on the pump hub, 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.
4. Hold the pump in place, tighten the adjusting arm bolt and then inspect the belt tension. When the belt is properly tensioned tighten the mounting bolts.

1973 AND LATER V8 MODELS

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 about 1?4 in. (6mm).
2. To adjust the belt tension, loosen the three bolts in the three elongated adjusting slots at the power steering pump attaching bracket.
3. 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.
4. Without disturbing the pump, tighten the three attaching bolts. Fig. 2: Power steering belt adjustment (slider type)
   

Air Conditioning Compressor Drive Belt

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 not exceed 1?4 in. (6mm).
2. If the engine is equipped with an idler pulley, loosen the idler pulley adjusting boot, insert a prytool 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 adjust, as outlined under Alternator Drive Belt.
3. When the proper tension is reached, tighten the idler pulley adjusting bolt (if so equipped) or the alternator adjusting and mounting bolts. Fig. 3: Air conditioning belt adjustment
   

Thermactor® Air Pump Drive Belt

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 about 1?4 in. (6mm).
2. To adjust the belt tension, loosen the adjusting arm bolt slightly. If necessary, also loosen the mounting belt slightly.
3. Using a prytool, pry against the pump rear cover to move the pump toward or away from the engine as necessary. WARNING
   Do not pry against the pump housing itself, as damage to the housing may result.
   
4. Holding the pump in place, tighten the adjusting arm bolt and recheck the tension. When the belt is properly tensioned, tighten the mounting bolt. Fig. 4: Air pump adjustment points
   

slacken the alternator bolts then slip the belt on the pulleys,using a long screwdiver behind the alternator,lever it out to tighten belt so that the longest part of the belt between pulleys has 1/2 inch movement(too tight and your alternator will need new bearings very soon...)then do up the bolts,check belt tension after all bolts tight to confirm not to tight/loose.

The belt is adjusted by the position of the alternator. Loosen the bottom mounting bolts. Loosen the adjusting bolt in the top bracket & using a suitable lever, pry the alternator outwards until the belt is tight. Do not tighten it too tight. you should be able to deflect the belt down about 3/4 -1" when tightened. Hold the bar to maintain this tension on the belt and tighten the top adjusting bolt. Re-tighten the two bottom bolts. Check the deflection of the belt once more to ensure it is not to tight.

it isnt that hard actually

disconect positive battery terminal. and feel the tension on the laternator belt. you will need to bring it back to this tension.

1.) loosen bolts holding alternator in place (LOOK AT THE BELT TO REMEMBER HOW IT GOES, BEST NOT REMOVE THE BELT.)

2.) loosen bolts holding wires to alternator and connect wires to new alternator

3.) Place alternator in engine, replace bolts but dont tighten

4.) put belt in place, it will be slack, use your tire iron or a piece of pipe or wood to pry the alternator back, to bring tension on the belt. You pry the alternator to pull the belt as TIGHT AS POSSIBLE. while holding strain, on it, tighten the bolts.

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Accessory Drive Belt Tensioner
Removal & Installation To Remove:

1. Rotate the accessory drive belt tensioner clockwise.
2. Remove the accessory drive belt.
3. Remove the accessory drive belt tensioner bolts.
4. Remove the accessory drive belt tensioner.

To Install:

1. Install the accessory drive belt tensioner.
2. Install the accessory drive belt tensioner bolts. Tighten to 18 ft-lb (25 Nm).
3. Install the accessory drive belt.
4. Rotate the accessory drive belt tensioner counterclockwise.

Hello! It's because the bolt is also the shaft that the tensioner rides on - therefore it needs to spin freely on the bolt. Hope that makes sense, and helps!


-KC GTO Dad