Wobbly Alternator Belt - Cause?

[bulletpruf]

Ok, so I have a 1991 F350 7.3; it has v-belts. The alternator belt was wobbly so I decided to change them out this weekend when I did a coolant flush and radiator hose change.

Anyway, the alternator belt was still wobbly with the new belt and I got it nice and tight. It's bad enough to where I'm a bit concerned driving it as-is. What's odd is that the vacuum pump belt is on the alternator pulley too and it's fine; no wobble at all.

Any thoughts on why this is? I thought it might be a bit loose so I tightened it up a bit and the wobble was still there.

I have video but I'm not sure how to upload it here.

Scott

 

[Nero]

Back when my rig had v belts, it wobbled too. Did it for years no issues. As long as it is properly tensioned, I wouldn't sweat it.

 

[Cubey]

I will only run Gates Fleetrunner for the alternator, power steering, AC. Regular Gates for the vacuum pump. It can be hard to tension the alternator. I have good luck using an old, slightly bent one of these as leverage between the alternative and the thermostat housing, even on vans where you can't get much of anything else in there.

https://www.harborfreight.com/24-inch-general-purpose-tire-iron-93230.html

 

[tradergem]

I use a big wrench on the square lug on top of my alternator to tension the belt.

 

[bulletpruf]

I use a big wrench on the square lug on top of my alternator to tension the belt.

Didn't think about using that. I'll see if I can get it a bit tighter and see if that helps.

 

[Nero]

If that doesnt work, Ive had success in the past using a crowbar between the thermostat housing and the alternator case. Just dont go too crazy with it.

 

[bulletpruf]

If that doesnt work, Ive had success in the past using a crowbar between the thermostat housing and the alternator case. Just dont go too crazy with it.

That's what I did, but I may be able to get it tighter by using the lug on the alternator.

 

[ROCK HARVEY]

I’ve kicked around the idea of adding a spring-loaded idler pulley to the alternator belt to stop the wobble. Maybe something that was meant for a lawn mower deck belt can be adapted, or a belt tensioner meant for a serpentine belt can be modified to fit.

 

[IDIBRONCO]

Back when my rig had v belts, it wobbled too. Did it for years no issues. As long as it is properly tensioned, I wouldn't sweat it.

I agree with this. They only run that way at and slightly above an idle. Any more RPM usually makes them run "straight".

 

[Jesus Freak]

There's a couple guys that made spring loaded tensioner idler pulleys because they didn't like the way it looked or something.

 

[Old Goat]

I use to use some type pry Bar to pull the Alternator over.
It still flopped around.
Then someone mentioned the Block on the Alternator, and I
had this DUHHH moment, like why didn`t I see that?
Just don`t over do it, I imagine too tight might not be too good
on the Alternator Bearings.

As long as we are in this area of the engine, be sure to throw on some Loc-Tite on the Vacuum Pump bolts if you loosen and adjust it.
I lost one bolt and threw the belt. Opened the Hood and there it was swinging on one Bolt. 3AM out here in the bad lands on Nevada.


Goat

 

[The_Josh_Bear]

Check out this link for my V-belt wobble hack. Still going strong!

Alternator Idler Pulley for V-Belts?

Anyone ever come up with the perfect idler pulley to take the slack out of the alternator belt so it will live longer? Searched for it but got nothing but serpentine. Thanks.

www.oilburners.net

 

[bulletpruf]

Check out this link for my V-belt wobble hack. Still going strong!

Alternator Idler Pulley for V-Belts?

Anyone ever come up with the perfect idler pulley to take the slack out of the alternator belt so it will live longer? Searched for it but got nothing but serpentine. Thanks.

www.oilburners.net

Thanks for posting that!

 

[MtnHaul]

The alternator v-belt always seems to have a little wobble but it never causes a problem. I would be more concerned about over-tightening and needlessly stressing something else. At least 100k on my alt belt with a wobble.

 

[clakelaw]

I have a 92 E350 which I believe is a little different, however I will say as stated above that the GREEN GATES Heavy Duty belt is the only one that lasts. This design was poor. Option 2, Classic Diesel Designs sells an alternative belt that just goes from the waterpump to the alternator. This corrects the issue, you do lose a little redundancy though.