Squealing Belt

[hrbergeron]

I'm stuck and don't know what to do. Here's what happened

M1009 Cucv Blazer, still 24v, glow plugs are not bypassed.

-Originally had no alternators when I bought the vehicle, bought two of them off Ebay. Both isolated ground 100ish amp alternators. All new gates belts.

-Driver side worked fine, passenger side started to squeal after about 1.5 hours of use. Sent back the alternator and received a rebuilt alternator.

-Installed the new alternator and started the cucv last night for around 1 minute, no squeal, putting out proper voltage.

-Started the vehicle today and it squeals as bad as the one i sent back in originally. I recieved a completely different alternator. This appears to be a decent quality delco-Remy unit.

Only difference between today and yesterday is that I ran down the batteries a bit while I was fixing all the vehicle lights.

The belt is tight, I tried it at varying tightness with the same result. The vehicle is still 24v. The pulley is too hot to hold your hand on.

What should I do next? New alternator? New belt? I do not have the time to send in this unit for a replacement.

 

[doghead]

Charge and load test your batteries.

And tighten the belt more if they test good.

Are you sure you have the right pulley on the alternator and the right belt?

 

[DeadParrot]

Measured the pulley on my alts. 3" pulleys.

Hard to tell with the black belt on the black pulley with the dark background but is the top of your belt pretty close to flush with the top of the pulley? In too far, it might be bottoming out. Out too far and you loose grip area.

 

[cucvrus]

Here's a little trick that I use on many belt applications including CUCV's for 25 years of private ownership. Drive to the parts dealer. Take the belts off in the parking lot. Go in and out with each belt until you get one that fits so tight it barely fits in the fully collapsed position of the pulley. Tighten the rear 2 as power steering first and gen 1 next. Keep in mine if you need to use a socket to nudge the belt on using the alternator nuts it will fly. I have used this on plow trucks and every other V belt application as a method to get the correct belts. Back when GM made the original belts they worked. I threw the belt numbers in the trash and get each belt per fit and get them as tight as possible in the loosest position. I mean I do not like V belts anymore but I work with what I have and it seems to work for me and others. Good Luck. You got this. August 1 already. Snow will be blowing in soon.

 

[hrbergeron]

It's the bearing. I find it hard to believe that two alternators in a row go bad soon after use and it's the bearing both times. Perhaps it is just poor quality bearings being used.

 

[nyoffroad]

It's the bearing. I find it hard to believe that two alternators in a row go bad soon after use and it's the bearing both times. Perhaps it is just poor quality bearings being used.

Could be cheap bearings or could it be your tightening the belt to much? I've had a few CUCV's and some took different sized belts than the others, not much maybe 1/2"-1" but that can be the difference between a squeal and not squealing. I also had a civvie 6.2 that all belts I tried would wear and squeal, turned out all the belts where "will fit" and not the recommended GATES that had a slightly different angle to them. As far as I know the CUCV's aren't like that but could someone have changed the pullies in the past???

 

[hrbergeron]

I believe I found the problem. I got a replacement bearing from the local auto parts place and replaced it. While I had it apart I noticed both brushes were cracked and broken. My theory is that part of the broken bits found their way into the bearing and caused issues. I installed the new bearing and new brushes I had laying around and I do not have any issues (at this time).