Marty, any progress on this? Just curious, and possibly a learning point for the rest of us.
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| Alternator belt stretching too much https://www.slantsix.org/forum/viewtopic.php?t=62145 |
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| Author: | mrtc4w [ Wed Mar 28, 2018 4:41 pm ] |
| Post subject: | Alternator belt stretching too much |
I bought a 1982 Plymouth Gran Fury w/Slant 6. It only had 38K miles on it. The belts were MoPar. I don't know if they are original or replacement. The car sat for a few years so I replaced them with AutoZone belts. The P/S and A/C belts are fine, but the Alt belt needed constant readjustment. It eventually came off, I caught it before it overheated too much. I decided to got to Dayco belts. I replaced it and all was good. I ran some errands and when I restarted it after one stop and the belt squealed loudly! It was loose again The alternator is not moving, it is the belt stretching. The pulleys appear to be lined up. I may put the MoPar belt back on to see if it does the same thing. In another lifetime I made my living as a Certified Mechanic. I don't remember this situation before. Any help is greatly appreciated. Marty |
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| Author: | Charrlie_S [ Wed Mar 28, 2018 5:45 pm ] |
| Post subject: | Re: Alternator belt stretching too much |
Is there rust on any of the pulleys? It will act like sandpaper on the belts. Then they will ride lower in the groove, and be loose. Then they start slipping and wear more, ride lower, slip, etc. |
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| Author: | mrtc4w [ Wed Mar 28, 2018 5:54 pm ] |
| Post subject: | Re: Alternator belt stretching too much |
Quote: Is there rust on any of the pulleys? It will act like sandpaper on the belts. Then they will ride lower in the groove, and be loose. Then they start slipping and wear more, ride lower, slip, etc.
No, they are nice and smooth.Marty |
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| Author: | wjajr [ Thu Mar 29, 2018 5:07 am ] |
| Post subject: | Re: Alternator belt stretching too much |
Are all the pulleys in alignment, or rather the same plane? My power steering pump was cocked out of alignment and would derail at high rpm, get caught up in alternator pulley, and derail that one. Ka-Boom baby, belt-less and blowing out a cloud like a Stanley Steamer in heat. Could be your belt is wearing one side enough to cause it to run too deep in pulley groove then it bottoms out. |
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| Author: | DusterIdiot [ Thu Mar 29, 2018 5:36 am ] |
| Post subject: | Re: Alternator belt stretching too much |
I would look at the Alternator lower bracket... being a 1982, it is the stamped sheet metal version that isn't as stout as the early cast pieces and tend to crack around the mount bolt holes... I know the one on my son's car lets the alternator vibrate a lot more than what I am comfortable with... |
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| Author: | mrtc4w [ Fri Mar 30, 2018 10:45 am ] |
| Post subject: | Re: Alternator belt stretching too much |
Quote: I would look at the Alternator lower bracket... being a 1982, it is the stamped sheet metal version that
I'll check it today. Thanks,isn't as stout as the early cast pieces and tend to crack around the mount bolt holes... I know the one on my son's car lets the alternator vibrate a lot more than what I am comfortable with... Marty |
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| Author: | Louise76 [ Sat Mar 31, 2018 10:43 am ] |
| Post subject: | Re: Alternator belt stretching too much |
"The alternator is not moving.."??? It should turn freely with light finger pressure when the belt is off. Is it binding inside? |
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| Author: | Pierre [ Sat Mar 31, 2018 10:13 pm ] |
| Post subject: | Re: Alternator belt stretching too much |
Pretty sure he/she meant the alternator isn't pivoting inward towards the engine, rather then not rotating.... The alternator / water pump belt is driven directly off the groove in the vibration dampener. The groove is bonded to the central hub with rubber that often dries and disintegrates with age, leaving the outer pulley to wobble. The next time the belt is off make sure the vibration dampener is in good order. The dampener may be sandwiched by two other pulleys bolted to the inside / outside of it (bolted to the central hub, that is). |
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| Author: | mrtc4w [ Sun Apr 01, 2018 6:26 pm ] |
| Post subject: | Re: Alternator belt stretching too much |
Quote: "The alternator is not moving.."???
By not moving I meant it is not moving on the bracket.It should turn freely with light finger pressure when the belt is off. Is it binding inside? Marty |
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| Author: | mrtc4w [ Sun Apr 01, 2018 6:27 pm ] |
| Post subject: | Re: Alternator belt stretching too much |
Quote: Pretty sure he/she meant the alternator isn't pivoting inward towards the engine, rather then not rotating....
Thanks, I'll check it.The alternator / water pump belt is driven directly off the groove in the vibration dampener. The groove is bonded to the central hub with rubber that often dries and disintegrates with age, leaving the outer pulley to wobble. The next time the belt is off make sure the vibration dampener is in good order. The dampener may be sandwiched by two other pulleys bolted to the inside / outside of it (bolted to the central hub, that is). Marty |
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| Author: | Louise76 [ Sat Apr 14, 2018 10:29 am ] |
| Post subject: | Re: Alternator belt stretching too much |
Marty, any progress on this? Just curious, and possibly a learning point for the rest of us.
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| Author: | mrtc4w [ Tue May 01, 2018 8:30 pm ] |
| Post subject: | Re: Alternator belt stretching too much |
Quote: Marty, any progress on this? Just curious, and possibly a learning point for the rest of us.
I have put ~500 miles on the new belts and have only retightened it once. The only thing now is it just started squealing when I start it cold.Marty |
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| Author: | Reed [ Tue May 01, 2018 8:53 pm ] |
| Post subject: | Re: Alternator belt stretching too much |
For what it is worth, I put new belts on my 82 Ramcharger when I got it a few months ago and I have had a constant problem with the new belts slipping and stretching. Both the power steering and alternator belt were new from Rockauto. Both have had to be repeatedly retightened. Both the alternator and the power steering pump are almost at the end of their adjustment. I need to replace them again, but I am trying to hold off replacing them until I add AC to the vehicle. Maybe the quality of replacement v-belts is dropping? |
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| Author: | Dart270 [ Wed May 02, 2018 3:22 am ] |
| Post subject: | Re: Alternator belt stretching too much |
Try to find Gates or Goodyear belts. Dayco used to be good too, IIRC, but who knows... If it's really cheap, it's probably crap. Lou |
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| Author: | mrtc4w [ Wed May 09, 2018 6:16 pm ] |
| Post subject: | Re: Alternator belt stretching too much |
I was at a friends shop and we were discussing this situation. There were three of us there and each had a different opinion if the pulleys were lined up. Today I pulled the belt off and tried to get a straight edge long enough to check. I spun the alternator pulley and it spun freely, but I could hear and feel a roughness in the bearing. I pulled the alternator and found a cracked housing. After installing the new alternator, it starts easier, a miss at idle that recently started is gone, and idle is smoother. I can only guess at idle it was slipping under load and causing low voltage to the ignition. The alt gauge has never moved a lot, so I never noticed any issues with charging at idle. I'll continue to check the belt tension. Hopefully this issue is over. Marty |
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