alternator belt damage

D

Deb

New member
Oct 23, 2016
358
6
3
Checking out my a/c system (finding all of the bits and pieces, compressor, lines, hoses & belts), and when I opened the hatch to get a closer look at
the compressor, this is what I saw:
http://www.gmcmhphotos.com/photos/data/7218/medium/IMG_27061.jpg

From what I can see, this is my alternator belt? Crawled around underneath and couldn't see any other damage to it, no cracks, doesn't look dry.
Only this spot. Turned her on a couple more times to check the areas i can't access on my back or from the hatch, went back in and couldn't see any
other places like this.

What's happened here? And how big a job is this to replace? And what specific belt do I get? I have seen some threads talking about newer stock
replacement belts (same part # or listed as "replacement for") being the wrong size (10 vs 11 mm ) sitting too low (in the pulley I am assuming).
Wonder if that could have been the case here? Looks like the "lip" of those sections have caught on something and been popped off like a bottle cap.

I don't know if this was like this before my Victoria trip this month, since it seems to be just the one spot, could have been like that last summer
and I just never saw it because it wasn't in the right spot to view.

Thoughts?
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
Found a page in the GMC pages http://bdub.net/gmcmotorhome.info/BELTS.html saying I should be able to replace that belt without having to remove or loosen any
others. I can't see a way around the ac compressor belt though.
This exercise all began as I was trying to begin troubleshooting the AC system. :)
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
Deb, the easiest way to remove the AC belt is to cut it. Don't have to
loosen anything. But, if you want to replace the belt, you need to loosen
the bracket that lives below the compressor that goes to one of the water
pump studs. The bracket has a slot in it usually on the compressor end. You
will also have to loosen the long bolt and nut on the top of the compressor
nearest to the rocker cover. It is a P.I.T.A. Also, there is a mounting
bracket on the rear of the compressor near where the hoses connect to the
compressor that needs to be loose. That usually is enough to allow the
compressor to swing down and allow the new belt to go over the clutch
pulley. Then, all you have to do is snake the new belt around the fan
shroud, put it around the crank pulley and water pump pulley, use a pry bar
to apply tension to the compressor to tension the belt while tightening
those three fasteners. Easy, no?
Jim Hupy
Salem, Or

On Sun, Jun 30, 2019 at 2:02 PM Deb McWade via Gmclist <

> Found a page in the GMC pages http://bdub.net/gmcmotorhome.info/BELTS.html saying
> I should be able to replace that belt without having to remove or loosen any
> others. I can't see a way around the ac compressor belt though.
> This exercise all began as I was trying to begin troubleshooting the AC
> system. :)
> --
> Deb McWade
> Logan Lake, BC, CAN
> "Li'l Sister"
> '77 Kingsley, 403, EBL EFI;
> TZE167V101404
> It's Bigger on the Inside!
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Deb,
If your not sure as to how old the belts are, suggest you replace all and
record that.
Alternator belt is the farthest one in , so you'll need to undo the A/C
belt first.

On Sun, Jun 30, 2019 at 2:02 PM Deb McWade via Gmclist <

> Found a page in the GMC pages http://bdub.net/gmcmotorhome.info/BELTS.html saying
> I should be able to replace that belt without having to remove or loosen any
> others. I can't see a way around the ac compressor belt though.
> This exercise all began as I was trying to begin troubleshooting the AC
> system. :)
> --
> Deb McWade
> Logan Lake, BC, CAN
> "Li'l Sister"
> '77 Kingsley, 403, EBL EFI;
> TZE167V101404
> It's Bigger on the Inside!
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Actually the ac belt seems fine Jim H. Its the alternator belt that's done in. I wasn't clear in my post. And the picture is really too close up
to be obvious. I discovered it when I was getting familiar with my ac system.

I got some info on replacing that belt without having to do anything with any of the others. Once I get the correct belt I'll give it a go.

Jim K, good idea, but the belts are all ~4 years old. Engine was rebuilt and installed in 2015 and new belts used, so the reason for this one has to
be the wrong size for the pulley depth. I'd rather not remove and re-tension good belts if I don't have to :). Especially that ac belt based on what
Hupy has to say about it! The fewer PITAs there are, the better.
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
You do run the risk of cutting the belt if you lay it on a pulley and force another belt to go over it.
I know some do it that way and I even did it once but it did put a gouge in my new belt.
It's not that difficult to loosen the other belt and retention it.

Emery Stora

>
> Actually the ac belt seems fine Jim H. Its the alternator belt that's done in. I wasn't clear in my post. And the picture is really too close up
> to be obvious. I discovered it when I was getting familiar with my ac system.
>
> I got some info on replacing that belt without having to do anything with any of the others. Once I get the correct belt I'll give it a go.
>
> Jim K, good idea, but the belts are all ~4 years old. Engine was rebuilt and installed in 2015 and new belts used, so the reason for this one has to
> be the wrong size for the pulley depth. I'd rather not remove and re-tension good belts if I don't have to :). Especially that ac belt based on what
> Hupy has to say about it! The fewer PITAs there are, the better.
> --
> Deb McWade
> Logan Lake, BC, CAN
> "Li'l Sister"
> '77 Kingsley, 403, EBL EFI;
> TZE167V101404
> It's Bigger on the Inside!
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
> Then, all you have to do is snake the new belt around the fan
> shroud, put it around the crank pulley and water pump pulley, use a pry bar
> to apply tension to the compressor to tension the belt while tightening
> those three fasteners. Easy, no?
> Jim Hupy
> Salem, Or

Piece of cake, Jim :lol:
And considering what Emory has to say about potentially gouging that spankin' new belt, I think I'll do it the old fashioned way, according to Hoyle.
How hard could it be? Right? 🤬

Just need to get the right belt. Start that hunt tomorrow.

BTW, based on what you see of the existing belt, what are my chances if I continue to drive it? Anyone care to start a pool?
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
Got a look at the label on the belt with my snake cam and it is a Dayco, Top-Cog belt. # 15575, not 15570. The specs of the 15575 give it a length
of 57.5", while what I get on the 15570 shows a 57". Both are 0.44" (11.1 mm) and 36 degree angle, so depth should be the same. When I look at the
specs of the original GM belt, it shows as a 57.5" length. Could it be that this is the wrong belt? Is the difference in effective length from the
original GM belt due to the cogs making it easier to wrap around that alternator pulley, so we need less belt? Would that extra 0.5" of length and
circumference make any difference? It seems to be the only difference that I can see.

And I have also been doing some googling on the damage to those cogs. On another site (snowmobiles :) ) some reported the same problem with the cogs
being ripped off on just the one side, like mine. Theirs were hitting a guard of some sort. I can't see where that could be happening with this one,
but the damage does appear to be on the front facing edge of the belt only. Could there be a problem with a misaligned pulley?

I have a source for the Dayco belt (either the 15575 or 15570), but before I go replacing the belt, I would like some idea of what caused this problem
in the first place. Anyone have any ideas?
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
Take a 10mm open end wrench, and place it over the width of the belt. If it
fits, the belt is too narrow. If it goes to the bottom of the pulley,
either the pulley is worn out, or the belt is too narrow. Be sure to check
this.
Jim Hupy

On Mon, Jul 1, 2019, 12:27 PM Deb McWade via Gmclist <

> Got a look at the label on the belt with my snake cam and it is a Dayco,
> Top-Cog belt. # 15575, not 15570. The specs of the 15575 give it a length
> of 57.5", while what I get on the 15570 shows a 57". Both are 0.44" (11.1
> mm) and 36 degree angle, so depth should be the same. When I look at the
> specs of the original GM belt, it shows as a 57.5" length. Could it be
> that this is the wrong belt? Is the difference in effective length from the
> original GM belt due to the cogs making it easier to wrap around that
> alternator pulley, so we need less belt? Would that extra 0.5" of length
> and
> circumference make any difference? It seems to be the only difference
> that I can see.
>
> And I have also been doing some googling on the damage to those cogs. On
> another site (snowmobiles :) ) some reported the same problem with the cogs
> being ripped off on just the one side, like mine. Theirs were hitting a
> guard of some sort. I can't see where that could be happening with this
> one,
> but the damage does appear to be on the front facing edge of the belt
> only. Could there be a problem with a misaligned pulley?
>
> I have a source for the Dayco belt (either the 15575 or 15570), but before
> I go replacing the belt, I would like some idea of what caused this problem
> in the first place. Anyone have any ideas?
> --
> Deb McWade
> Logan Lake, BC, CAN
> "Li'l Sister"
> '77 Kingsley, 403, EBL EFI;
> TZE167V101404
> It's Bigger on the Inside!
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Deb,
On our Air Filter division, we sell tremendous amount of Industrial V
belts. Coged ones are prefered by many , but the other ones with raw sides
work equally as well.
What is important is the tension, when new, the belt rides high on the
pulley and wears in lower into the pulley and most people think the belt
stretched.
Our factory reps tell us that the belts do not stretch.
I recommend that a new belt be tightened little more snug.

On Mon, Jul 1, 2019 at 12:27 PM Deb McWade via Gmclist <

> Got a look at the label on the belt with my snake cam and it is a Dayco,
> Top-Cog belt. # 15575, not 15570. The specs of the 15575 give it a length
> of 57.5", while what I get on the 15570 shows a 57". Both are 0.44" (11.1
> mm) and 36 degree angle, so depth should be the same. When I look at the
> specs of the original GM belt, it shows as a 57.5" length. Could it be
> that this is the wrong belt? Is the difference in effective length from the
> original GM belt due to the cogs making it easier to wrap around that
> alternator pulley, so we need less belt? Would that extra 0.5" of length
> and
> circumference make any difference? It seems to be the only difference
> that I can see.
>
> And I have also been doing some googling on the damage to those cogs. On
> another site (snowmobiles :) ) some reported the same problem with the cogs
> being ripped off on just the one side, like mine. Theirs were hitting a
> guard of some sort. I can't see where that could be happening with this
> one,
> but the damage does appear to be on the front facing edge of the belt
> only. Could there be a problem with a misaligned pulley?
>
> I have a source for the Dayco belt (either the 15575 or 15570), but before
> I go replacing the belt, I would like some idea of what caused this problem
> in the first place. Anyone have any ideas?
> --
> Deb McWade
> Logan Lake, BC, CAN
> "Li'l Sister"
> '77 Kingsley, 403, EBL EFI;
> TZE167V101404
> It's Bigger on the Inside!
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Deb,

I have only a little experience with Dayco Top Cogs, but most of it was good. I have seen similar damage to belt where the sheaves were out of line.
This is very easy to do and not easy to detect. As that is the only Top Cog and the A/C and PS belts look fine, I suggest that you look carefully at
the alternator alignment.

To eyeball check the alignment, get you face where you can see the edges of the alternator sheave and visually line those up with the corresponding
edges of the others. If it does not, then fixing it may be an "adventure".
"We are plain quiet folk and have no use for adventures. Nasty disturbing uncomfortable things! Make you late for dinner! I can't think what anybody
sees in them." Bilbo Baggins

You will have to unload the A/C belt to R&R that belt, no way around that. You can, if the A/C belt is way loose, pass a belt under it at the
crankshaft and the water pump, but if you are not sure how to do that, do not even try. If you cut (may not be visible) the new belt, it is
guaranteed to let go at the least opportune moment.

Matt - off to the adventures in my barn
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Thanks Jim's ;) I'm going to order the 15570 belt (might order both since the shipping will be the same!) and I'll check the width with a wrench.

And Matt - thank you for another adventure! The other belts do look OK from what I can tell. So I'll take a look at that alternator alignment
tomorrow afternoon or Wed. Today is now otherwise occupied as is most of tomorrow. I have an old mechanic living 2 doors down who is very happy to
assist with the belt re & re.
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
GM did not use cogged belts. And definitely did not use top cogged. I got this information from the head judge at a Buick Concourse national show. I'm
sticking with what they engineered as correct.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
I would just as soon go with what was used before. But can't seem to track anything down here in Canada of the same style. NAPA isn't getting back
to me. The Dayco belts were all that seemed to be available. And they're belts that GM considers as approved replacement for the OEM which is no
longer manufactured. It's either these or OEM NOS GM belts on eBay. And I'm not sure if I want to go with 20-30 year old rubber either. So 6 of
one?

If I can find something else I will give it a look. But in the meantime, I need a belt.... So I ordered the Dayco Top Cog
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
Here is what is bothering me with your picture First you have a top cog belt on the alternator. I have never seen a top cog belt ever used on a GMC.
The top cog alternator belt appears to be riding lower in the pulleys than the other two belts. If this is true, then you will have some minor
slippage and wear on the belts because they they are paired on some of the pulleys.

I would measure the width of ALL three belts and make sure that they are the same. The make sure the new one is the same width as the other. The
easy way would be to use a set of metric open end wrenches and see if the are the same width.

1/2" = 13 mm
7/16" = 11 mm
3/8" = 9.5 mm

The 1/2" difference in the two belts you mentioned will make no difference. There is only 1/4" of an inch difference in the alternator adjustment to
take out the slack.
do not use 9.5/10 mm (3/8") on a GMC. Measure it in the store before you buy it. Goodyear, Kelly-Springfield, NAPA (on there expensive belt line)
Dayco, and Autozone all have 7/16" belts. Gates and NAPA's regular brand (made by gates) definitely do not fit well. A couple of years ago I switch
to all 1/2 " belts. They are cheap and available from your local farm store or on line.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Deb,

THE place for belts is:
https://www.vbeltsupply.com/automotive-cogged-v-belts?p=7

Seems all of their automotive belts are inside cogged (but all 12mm wide at
top). If you want to try 1/2" belts, I'd suggest 4LK575 (Kevlar & longer
for "higher riding"). But then, I converted to serpentine belts LONG ago.

Ken H.

On Tue, Jul 2, 2019 at 5:02 AM Ken Burton via Gmclist <

> Here is what is bothering me with your picture First you have a top cog
> belt on the alternator. I have never seen a top cog belt ever used on a
> GMC.
> The top cog alternator belt appears to be riding lower in the pulleys
> than the other two belts. If this is true, then you will have some minor
> slippage and wear on the belts because they they are paired on some of the
> pulleys.
>
> I would measure the width of ALL three belts and make sure that they are
> the same. The make sure the new one is the same width as the other. The
> easy way would be to use a set of metric open end wrenches and see if the
> are the same width.
>
> 1/2" = 13 mm
> 7/16" = 11 mm
> 3/8" = 9.5 mm
>
> The 1/2" difference in the two belts you mentioned will make no
> difference. There is only 1/4" of an inch difference in the alternator
> adjustment to
> take out the slack.
> do not use 9.5/10 mm (3/8") on a GMC. Measure it in the store before you
> buy it. Goodyear, Kelly-Springfield, NAPA (on there expensive belt line)
> Dayco, and Autozone all have 7/16" belts. Gates and NAPA's regular brand
> (made by gates) definitely do not fit well. A couple of years ago I switch
> to all 1/2 " belts. They are cheap and available from your local farm
> store or on line.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Deb, Here is the belt that I used. I got two of them because I have a double pulley alternator so I have two alternator belts in place of the
standard 1 alternator and 1 PS belt arrangement.

https://www.vbeltsupply.com/a55-classic-belt.html

vbeltsupply.com
A55 V-Belt 1/2 inch Top Width X 57" (1447.8mm) Outside Measurement

Classic v-belts are just that, classic in design and application. The classic v-belt is the most tried and true style of v-belt in the market.
Originally designed to replace leather belts in a variety of industries including agriculture, facility maintenance, heating ventilation and air
conditioning (HVAC) and material handling. Also known as light duty v-belts, they are designed with a 40Ì° angle to "wedge" the belt into the groove
of the pulley. The greater the load, the greater the wedging action. The manufacturing process combines a rubber compound with a polyester cord to
increase strength and stability. Most classic belts are also available in Kevlar.

Conventional v-belt suitable for all standard industrial applications. Standard operating temperatures ranging from -1Ì° F through 158Ì° F.

ISO:9001 Certified

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Thank you Ken & Ken! I thought that belt looked low in the pulleys as well. That was why I thought it might be a 10mm (since I had read about that.
I am trying to find these things myself, but always happy to ask for and accept advice!) The reason I went with the Dayco Top Cog was from
information here: http://bdub.net/gmcmotorhome.info/BELTS.html. That 15570 part number is listed 3 or 4 times, so I went with it. Although the picture on the
first page says it's a Top Cog from Dayco, it didn't look too "Top Coggy" to me. But I went with the suggested part number since that was what I
could readily track down.

I will head out and check the sizing on all of the existing belts later today. (Really sick this morning). I was able to get hold of the place I
ordered the Dayco belt and they have cancelled it.

I will check the vbeltsupply site for the belt you suggested there Ken B. And now that things are open here (we had a long weekend too) I may be able
to find something locally, although I am not holding my breath on that.

Thanks again for the help.
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
Does this look like it would be what I am looking for? https://www.vbeltsupply.com/a55k-wrapped-kevlar-belt.html I have to see what shipping here
would be, but at that price, it still has to be better than what I was going to pay for the Dayco.
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
Deb,
The cog is not that important, the maufactures update the design so dont
waste your time on these detail . I have seen many years ago where the cog
was on top to help with flex.
Tension is more important.

On Tue, Jul 2, 2019 at 11:02 AM Deb McWade via Gmclist <

> Does this look like it would be what I am looking for?
> https://www.vbeltsupply.com/a55k-wrapped-kevlar-belt.html I have to see
> what shipping here
> would be, but at that price, it still has to be better than what I was
> going to pay for the Dayco.
> --
> Deb McWade
> Logan Lake, BC, CAN
> "Li'l Sister"
> '77 Kingsley, 403, EBL EFI;
> TZE167V101404
> It's Bigger on the Inside!
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
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