Alternator and belt squeel, help!

Brianut · Apr 1, 2011

just recently installed a 130A mustang alt in my truck and first thing in the morning when I start it i get a lower volt reading and belt slipping from my alt.

runs about 13. at the same mileage point of driving it will "tone out" to a high pitch and then stop, at the same time my volt gauge will jump up to 14.7ish.

the belt is a new standard 7 dollar belt, I have used belt conditioner with no luck.

the alt charges all the time so why does it squeel at startup only?

how do i stop it from slipping?

pulley have some shine, I did rough them up with some sandcloth dont really think that did anything.

are there some fancy belts out there that would be better?
could this belt have been sitting on the shelf and dried out?(dry climate here)

not only is it embarasing but I seem to see the same people every morning on my commute and feel like a D bag for not being able to stop the squeel.

RRRAAAYYY2 · Apr 1, 2011

Too much torque transfer for the cold belt. A bigger alternator pulley will help, retighten your tension first and see if that cures it. Shiney belt grooves in the pulley are a bad thing, but if you roughed them up, probably not the cause anymore.

Viperwolf1 · Apr 1, 2011

The battery is weakest just after startup so that's when the alt is charging the most. That charging makes it harder to turn so the belt slips. A bigger diameter pulley will give the belt more traction.

Brianut · Apr 1, 2011

what size and where would one find this larger pully?

J/Y or new at autozone or somewhere Bronco specific like WH?

72Sport · Apr 1, 2011

Look in the yellow pages and see if you have a starter/alternator re-builder locally. They just might trade you straight across. See how much room you have in the adjuster. Buy a longer belt. You will get more "belt wrap" around the pulley thus spreading out the load. Some have added a double groove pulley and another belt.

Starting the engine uses a lot of current causing the voltage to drop in the battery. Alternator tries to charge the battery back up quickly thus causing the slip or squeal.

chuckinphx · Apr 1, 2011

I got one from summit, get 3 inch one...stopped the squeel, replace the belt if its been squeeling for a while, youll see why when you have new and old sis by side.. all the slippin polishes the rubber ...

brocken · Apr 1, 2011

I think it was an earlier RRRAAAAYYY post I got my info from but I went with a 3-1/4" x 1/2" pulley on my 3G alt.
No more squeal!
You do get less output with the larger diameter but it should still be enough to power your Bronco electrical items.

I had the same slippage after startup when it's refreshing the battery. I also had slippage when I mashed the throttle.
It's so nice not having to listen to that squeal anymore. And I'm glad I didn't have to spend the time and money doing a serp conversion.

Find a local alternator/starter shop and they should be able to get the pulley for you. My shop charged $15 and that included installing the new pulley.

bad 68 · Apr 1, 2011

Heres the part number for the larger pulley for the 3G. 24-1104
It seems to be easy to reference with this number without needing an application.
As stated earlier it is 3.2"
measure your old pulley and see if it is less than 3 inches or wider than .5" in the widest part of the grove. If so than the new pulley should solve your problem.

moe d · Jun 4, 2011

bad 68 said:
Heres the part number for the larger pulley for the 3G. 24-1104
It seems to be easy to reference with this number without needing an application.
As stated earlier it is 3.2"
measure your old pulley and see if it is less than 3 inches or wider than .5" in the widest part of the grove. If so than the new pulley should solve your problem.

can u get that pulley at summit or jegs or one of the CB vendors?

blubuckaroo · Jun 4, 2011

Make sure the belt isn't running at the bottom of the pulley grooves. The belt needs to be wide enough that the belt wedges into the pully groove and grips it. If it rides on the bottom, no amount of belt tension will help.

rmfreeze · Jun 4, 2011

Mine will do it if the battery isn't charged up (sitting for a few days/weeks). Once charged I get about 0-2 seconds of a squeal at start-up. Make sure the battery is topped and good. Otherwise, a slightly bigger pulley or tighter belt might help.

moe d · Jun 6, 2011

bad 68 said:
Heres the part number for the larger pulley for the 3G. 24-1104
It seems to be easy to reference with this number without needing an application.
As stated earlier it is 3.2"
measure your old pulley and see if it is less than 3 inches or wider than .5" in the widest part of the grove. If so than the new pulley should solve your problem.

i'm finding this part number is for a john deere, is this correct? measurements are correct

Pulley - 1-Groove

For: Delco 10SI/Type 116 Series IR/EF Alternators

Used On: John Deere

Replaces: John Deere R52159

Dimensions: 13mm Belt x 81mm OD x 17mm Bore

Features: Machined pulley cut from cold rolled steel

WAI Part No. 24-1104
Dubois Part No. 191-001

broncotime · Jun 6, 2011

moe d said:
i'm finding this part number is for a john deere, is this correct? measurements are correct

Pulley - 1-Groove

For: Delco 10SI/Type 116 Series IR/EF Alternators

Used On: John Deere

Replaces: John Deere R52159

Dimensions: 13mm Belt x 81mm OD x 17mm Bore

Features: Machined pulley cut from cold rolled steel

WAI Part No. 24-1104
Dubois Part No. 191-001

Post up what you find out on exactly what fits. I have the same problem with my 3G squeek and it drives me crazy. Larger pulley makes sense, but a store location (IE AutoZone, Oriley's etc) and a part number would be great to have to save me some time.
Thanks

Alternator and belt squeel, help!

Brianut

Jr. Member

RRRAAAYYY2

Bronco Guru

Viperwolf1

electron whisperer

Brianut

Jr. Member

72Sport

Bronco Guru

chuckinphx

Full Member

brocken

Full Member

bad 68

Sr. Member

moe d

Sr. Member

blubuckaroo

Grease Monkey

rmfreeze

Sr. Member

moe d

Sr. Member

broncotime

Bronco Guru

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