Alternator belt tension or bad bearings?

[HesseniusM1009]

Belt/Alternator question: my passenger side alternator belt was squeaking until it warmed up and I noticed it was so loose it was flapping and rubbing against the alternator fan. I adjusted the alternator to make the belt tight and the squeak went away for a couple miles then the driver side belt started squeaking when accelerating. I touched the pulley and it was super hot to the touch after running a short time. So I replaced both belts with the exact same belts from Napa and now no more squeaking but both alternator pulleys are getting super hot.

Are the pulleys getting hot because the tension isn’t right on my belts or are the bearings going out? I’m really not sure how tight or loose the belts should be. It’s odd only one pulley was hot before I swapped belts and now they both are.
Thanks for any advice!

 

[sneekyeye]

Can you remove the belt and turn the pulley by hand and see if there is any roughness or grit in the bearings? That would be the easiest test.

I was driving down the road when I had a bearing fail on my left alternator. The pulley dropped and locked in place while the engine was running at a stop light. It smoked real bad for a while and made an awful squealing until it let loose. It was not hard to replace the bearings in the case, but you can crack the case if done improperly.

 

[HesseniusM1009]

There is some roughness and a slight wobble in the drivers side. The passenger side spins okay without a wobble both are heating up now though

Can you remove the belt and turn the pulley by hand and see if there is any roughness or grit in the bearings? That would be the easiest test.

I was driving down the road when I had a bearing fail on my left alternator. The pulley dropped and locked in place while the engine was running at a stop light. It smoked real bad for a while and made an awful squealing until it let loose. It was not hard to replace the bearings in the case, but you can crack the case if done improperly.

 

[cucvrus]

Are the batteries load tested and fully charged? Have the resistors on the firewall been bypassed? I always get a belt the fits about tight with the alternators fully retracted and tighten from there. I drive to the local parts store and walk in and out till I find one that fits nice and tight. I even use a wrench to turn the alternator to get the bel on. Worked for me for 27 years and no squealing belts anymore. I have no set part number for belts. I just put on and use what fits snug and tight in a close to fully retracted as possible position. Gives me lots of room to adjust if needed. Most I see are almost fully out and new. Good Luck.

 

[HesseniusM1009]

the batteries are charged and my volt meter shows around 12-13 when not running at 14 when running. I can make the belts so tight the alt fans won’t even spin so tightness isn’t the issue. How tight is too tight?

Are the batteries load tested and fully charged? Have the resistors on the firewall been bypassed? I always get a belt the fits about tight with the alternators fully retracted and tighten from there. I drive to the local parts store and walk in and out till I find one that fits nice and tight. I even use a wrench to turn the alternator to get the bel on. Worked for me for 27 years and no squealing belts anymore. I have no set part number for belts. I just put on and use what fits snug and tight in a close to fully retracted as possible position. Gives me lots of room to adjust if needed. Most I see are almost fully out and new. Good Luck.

 

[adf5565]

Granted I’ve never used these specs, just played with adjustments until it felt right. But this is what the service manual says.

 

[HesseniusM1009]

I got these specs out of the TM but don’t know what that means in layman terms. I ordered a gates tension gauge that goes up to 160 so I’m hoping that’ll help. I just didn’t know how tight or loose they should be at all in the meantime

Granted I’ve never used these specs, just played with adjustments until it felt right. But this is what the service manual says.

View attachment 883062

 

[porkysplace]

Has the harmonic balancer ever been changed ?
If not you may want to check that .

 

[87cr250r]

One thing to note, you MUST use the Gates belts on these configurations. All others I have tried are too stretchy and loose tension too fast.