HELP! belts burned up

[red 69 runner]

Today I thought I would do something simple like replace my belts on my 69 RR. It has the original 383 with factory A/C (compressor is still mounted onthe motor but not hooked up to the system yet)ok the motor only had 1 belt for the alternator and compressor installed ever since I have owned the car and it would squeel when you would rev it up so I bought 2 new belts as well as the power steering belt and the fan belt,installed and tightened everything so I thought but when I started it up the 2 alternator belts started to squeel and I looked and they were way to loose so I tightened them up with no play,started it up again and they started smoking and when I looked the alternator pully wasnt turning,burnt the new belts up pretty quick,I loosened everything back up and the alternator turns free and so does the A/C compressor.could it be that my alternator is locking up with the belts tight,Can you overtighten belts,I would think the tighter the better,I was going to get a new alternator but i thought I would post here and get some advice first,car was running great with 1 belt but now even with 1 belt tightened the alternator acts like it is locked up but turns free with no belts on it.I am :angryfire:

 

[Mopars & Missiles]

Is the bolt on the adjuster bracket that goes into the bottom of the alternator too long? If so, when you adjust and tighten the belts it will lock up the alternator. When you loosen the bolt to take the belts off, the alternator spins freely again.

 

[70rr-brian]

Could have been bad alt bearings that was squealing all along the more tension on bad bearing I would think would cause them to seize like you describe. You could loosen the belts and grab the alt pulley and see if it has any play in it moving the pulley up/down/left/right.

 

[YY1]

x2 on the bolt length.

Also make sure everything is lined up on the same plane the belt passes through.
(all the grooves line up when looking from the side, through the grooves to the next pulley)

 

[Mopars & Missiles]

Is the bolt on the adjuster bracket that goes into the bottom of the alternator too long? If so, when you adjust and tighten the belts it will lock up the alternator. When you loosen the bolt to take the belts off, the alternator spins freely again.

Another possibility,

Are the correct spacers on the main bolt that attaches the alternator to the engine head? If not, when you tighten this bolt it will squeeze the alternator case together causing internal interference.

 

[red 69 runner]

The bolt does not seem to be to long and it is the same one that has been on there,the long top bolt and spacer was suspect because when I took the bottom bolt all the way off the bracket came forward about 3/8" so I put some washers in to move the alternator forward so the lower bracket touches the alternator .the alighnment looks good but I need to put a straight edge on the pullys to check,i am beginning to think that this is the reason the PO only had 1 belt on ,I am picking up a new alternator and 2 new belts today and try it again,Ill let you know how it goes.Thanks

 

[red 69 runner]

Mopars and Miissiles you hit the nail right on the head,before heading out to work I went to take the alternator off so I could trade it in as a core,I cut the belt since it was ruined and went to tur the pully and it was locked up tight,so I left the bottom bolt tight and started to loosen the top bolt and the pully freed up,my alternator doesnt have a spacer between the 2 ears and when I tighten that bolt it compresses the case,i am going to make a spacer from a piece of 3/8" shedule 40 steel pipe that will fit between the 2 ears,should take care of the problem.Its funny when you take something apart you think all the parts are there because it worked before.I guess the top bolt was never as tight as I tightened it.Thanks again guys as always a lot of help here on this forum.

 

[coloradodave]

Mopars and Missles: Great call! Who'da thunk. I for one, appreciate your smarts...........sometimes things DO get solved around here. And thanks to red69runner for letting us know. I love it.

 

[red 69 runner]

just an update.1/4" steel pipe is what is needed 3/8" was to big.

 

[RustyRatRod]

is the bolt on the adjuster bracket that goes into the bottom of the alternator too long? If so, when you adjust and tighten the belts it will lock up the alternator. When you loosen the bolt to take the belts off, the alternator spins freely again.

this ^^^^

 

[RustyRatRod]

A lot of people also don't know this, but you NEED to have what's called a "matched pair" of belts for the alternator and A/C. That means they were both cut from the same slab of belt material and probably sequential, so they are exactly the same length. This is NOT unimportant. Although I do not think it contributed to your problem, it still should be addressed. Most big box "counter people" will give you a dumbfounded look when you ask for a matched pair of belts so you need to find a seasoned PARTS MAN. He will know.