Squeaky Alternator

[Kevinehill]

The alternator on my 1970 squeaks. Not always, but most of the time and the belt becomes very hot. It does seem to provide enough power to keep running and keep the battery changed. I had the problem with the original alternator and 2 years ago I switched to the 130 Amp replacement and it squeaks too. It has the V-belt and I am wondering if I can get a larger pulley wheel if it would give it more surface area and stop the squeaks. Your ideas please. Thank you for your time and suggestions.
Kevin

 

[Steve83]

Is the belt tight? Can you run a double-V pulley? Post pics of the belt routing, and along the plane of the belts & pulleys.

 

[bronconut73]

Sometimes just a "new" pulley makes a big difference.

I got a new v-pulley for my 3G and I was surprised how much more available friction to grab the belt was present compared to my original. My original only had about 49k miles and it was slick/polished. New pulley made an instant improvement. Then i went ahead and bought a really high quality belt (like $30 bucks vs $9 bucks). No more squeaks or squeals after that.

But if that doesn't do it for ya double pulleys are awesome at stopping slippage without having to over tighten the belt

 

[Kevinehill]

Sometimes just a "new" pulley makes a big difference.

I got a new v-pulley for my 3G and I was surprised how much more available friction to grab the belt was present compared to my original. My original only had about 49k miles and it was slick/polished. New pulley made an instant improvement. Then i went ahead and bought a really high quality belt (like $30 bucks vs $9 bucks). No more squeaks or squeals after that.

But if that doesn't do it for ya double pulleys are awesome at stopping slippage without having to over tighten the belt

Where did you get your new v-pulley and belt from? Thanks!

 

[Slednut10]

Here's a link to the slightly larger single groove I have on my 3G.
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=222146156714&_sacat=0

 

[bronconut73]

Where did you get your new v-pulley and belt from? Thanks!

EBay had an amazing selection and cheap.

Napa for the belt. Took awhile to get the perfect length.

 

[DirtDonk]

Is yours a squeak, or a squeal?
A squeak is rhythmic maybe, and goes more like a "chirp, chirp, chirp" where a squeal is a longer, drawn out high pitched sound that, in the case of alternators, usually happens immediately after starting up the engine, or when firing up a heavy load.
In many cases it's worse in the cold wet morning, or wet weather. Also will generally taper off as things equalize electrically.

If it follows that latter pattern it's a belt squeal. If the former, it could be a bearing as well as an odd belt/pulley issue.
Did you by any chance use the same pulley on both alternators? It's not common to have them squeal with a stock type alternator, but very common for belt squeal to follow a 3g install.

If you have the option with a new pulley, the slightly larger diameter is a good choice when sticking with v-belts. Dual is good too, but not always easy to fit with other accessories. But larger diameter gives the belt more area to grip.

Good luck.

Paul

 

[blubuckaroo]

The load of a 3Ag will certainly chirp a V-Belt.
The question I have is, why did you upgrade" to a 3Ag?
In my opinion, this upgrade is overkill in most cases.
If you want to see the backlash, all you need to do is Google 3AG.
Sure, more can be better. But in the case of alternators, a real upgrade means a lot more work than most want to do.

Do the research before doing it.

 

[Kevinehill]

Is yours a squeak, or a squeal?
A squeak is rhythmic maybe, and goes more like a "chirp, chirp, chirp" where a squeal is a longer, drawn out high pitched sound that, in the case of alternators, usually happens immediately after starting up the engine, or when firing up a heavy load.
In many cases it's worse in the cold wet morning, or wet weather. Also will generally taper off as things equalize electrically.

If it follows that latter pattern it's a belt squeal. If the former, it could be a bearing as well as an odd belt/pulley issue.
Did you by any chance use the same pulley on both alternators? It's not common to have them squeal with a stock type alternator, but very common for belt squeal to follow a 3g install.

If you have the option with a new pulley, the slightly larger diameter is a good choice when sticking with v-belts. Dual is good too, but not always easy to fit with other accessories. But larger diameter gives the belt more area to grip.

Good luck.

Paul

It is more of the long continuous, although it seems to be quiet at some RPMs. I did not use the same pulley when I put in the new Alternator and I put in a new belt at that time. I am thinking of rough sanding the pulley and if that does not help, I will purchase a new larger pulley and larger belt as suggested. Thanks!
Kevin

 

[DirtDonk]

When I did my first upgrade to a 70a large case 1G alternator I had the same issue. Didn't want to keep tightening the belt and just have the same issue I'd had with short life of bearings, so I finally went to a dual-sheave pulley.

However, in the meantime the longest period of time I went without squealing was after cleaning the groove with Chemtool carb cleaner AND sandpaper.
Went away for a few months that time. But finally went to dual belts and never had trouble again.
Easier on Broncos without power steering, but many members here are doing just that even with power steering pump belts to factor in.

Good luck. It'll be great when you don't have to listen to that music anymore!

Paul

 

[Kevinehill]

Okay, I believe I finally fixed this. I ordered a new pulley as suggested and put it in. Quiet! Drove around the block and quiet. Drove about 10 miles and after 3 it started squeaking, then after a mile or 2 it stopped, then started again, then stopped... So I order a new 100 A. alternator from Summit and put it in and it has been quiet since. I have driven it maybe 50 miles or so and no problems. I believe either the alternator was going bad or was just pulling to hard. Would have needed a 2 belt system and the replacement was easier. Thanks for all of your suggestions and help.

 

[DirtDonk]

A good result no matter what! Thanks for the follow up, but interesting result.
Let us know if anything crops back up down the road.

Paul

 

[Rustytruck]

Use a Goodyear Gatorback belt they are dimensional slightly wider and helps with the squeaks. I usually have to buy them from summit.

 

[Attac]

I put a 200 3G on my bronco and I have never bought another for any other of our broncos. The more amps it makes the more effort it takes to turn it. I went through every belt and pulley combo I could and could not make it stop squealing for more than a day. Finally got pi**ed off and bought the march performance serpentine setup. That fixed it but it was 600.00 and was a little tricky fitting fan away from pulleys and radiator.
It was way overkill for what I needed. I now get the 130s and run them with single belt and it powers everything perfectly. Have 2 set up that way now.
I am going straight to explorer setup on the new one we are building and eliminate all cooling and belt problems. Plus I will get better steering power
Chuck

 

[gavindg]

Use a Goodyear Gatorback belt they are dimensional slightly wider and helps with the squeaks. I usually have to buy them from summit.

Ditto on this.
This will help with any miss alignment.
Worked great on mine, just make sure you measure it correctly and by 2 sizes in case and return the one that does not fit.
Got mine off of Amazon.