I tried to replace my alternator belt on 77 k5 blazer 350. I keep breaking belts. It squels really bad until the alternator belt breaks. I tried shorter belts and the squels go away until I get to about 50 mph. Could it be water pump? Any help or ideas are appreciated!
CK5
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belt issues! please help
- Thread starter 19blaze77
- Start date
It sounds like your pulleys may be out of alignment.
Have you removed anything before this started happening?
It could also be a bad bearing behind a pulley or the harmonic balancer may be falling apart.
With the belt on, look for a wobble.
With the belt removed, check to see if the pulleys move freely.
Have you removed anything before this started happening?
It could also be a bad bearing behind a pulley or the harmonic balancer may be falling apart.
With the belt on, look for a wobble.
With the belt removed, check to see if the pulleys move freely.
Have not changed anything. Nothing seems to wobble and pulleys spin freely. Not certain but I don't see a
Have not removed anything and no wobble in pulleys and they spin freely. The only thing I can see different from the old belt and new one is width or thickness of the belt. The other belt that goes to my power steering looks like it sits deeper in the pullies. The autozine doesn't have a skinnier belt.
That's one of the reasons I stopped going to Autozone.
Maybe stop by O'Reillleys, Carquest, or Napa and see if they have the correct belt.
Maybe stop by O'Reillleys, Carquest, or Napa and see if they have the correct belt.
Carcinogen
1/2 ton status
Another thing it could be is a glazed pulley. Just throwing ideas out there...
What is that and how do I check for it?
The sides of the "V" in the pulley will be shiny like glass and feel slick if its glazed..if the alternator has been swapped,the pulley on it might not match up to the ones on the engine--some were made for belts 7/16" wide,others are wider for a 15/32" belt...so the belt only fits "some" of the pulleys right..use the right belt for a 7/16" wide pulley on the alternator on an engine with the wider pulleys,the belt rides on the bottom of the sheave and slips,and fails rapidly..
If the alternator only has a 7/16" pulley and you use the wider belt,it'll sit high in the alternator sheave and cut the "top" off the belt eventually..the belt should neither sit higher than the pulley,or be riding deep in it with some of the sheave showing..either condition kills belts in short order..
I've seen this happen a lot working a parts counter,often we'd end up taking the old pulley off the core and swapping it to a rebuilt for the customer..
If the belts are snapping though,I doubt thats the cause--the fact it is squealing indicates a heavy load,either the bearings are seizing up on one of the items it drives (water pump,alternator,etc),or there may be a heavy electrical load on the alternator due to a short circuit..usually a belt will smoke and get thin before it'll break...if it jumps out of the pulleys the fan or pulleys can cut it up and make it look like it broke,but in fact it was sheared off after the fact..once a belt flips and jumps off a running pulley its usually junk,it'll have a twist in the cords and will keep jumping off no matter how tight it is..
Edit..
Another thing as mentioned is alignment--make sure the crank and water pump ,alternator pulleys all line up,using a straightedge ...Chevy used a few different V belt style water pumps that stick out different distances from the block,and they often get put on the "wrong" engines..if only the water pump pulley seems "off",it probably has the wrong pump or pulley on it..
If the alternator only has a 7/16" pulley and you use the wider belt,it'll sit high in the alternator sheave and cut the "top" off the belt eventually..the belt should neither sit higher than the pulley,or be riding deep in it with some of the sheave showing..either condition kills belts in short order..
I've seen this happen a lot working a parts counter,often we'd end up taking the old pulley off the core and swapping it to a rebuilt for the customer..
If the belts are snapping though,I doubt thats the cause--the fact it is squealing indicates a heavy load,either the bearings are seizing up on one of the items it drives (water pump,alternator,etc),or there may be a heavy electrical load on the alternator due to a short circuit..usually a belt will smoke and get thin before it'll break...if it jumps out of the pulleys the fan or pulleys can cut it up and make it look like it broke,but in fact it was sheared off after the fact..once a belt flips and jumps off a running pulley its usually junk,it'll have a twist in the cords and will keep jumping off no matter how tight it is..
Edit..
Another thing as mentioned is alignment--make sure the crank and water pump ,alternator pulleys all line up,using a straightedge ...Chevy used a few different V belt style water pumps that stick out different distances from the block,and they often get put on the "wrong" engines..if only the water pump pulley seems "off",it probably has the wrong pump or pulley on it..
Thank you! This was very informative. I think I'll start with making sure pulleys are aligned and try to find a skinnier belt and see if that works. I have only had this problem after changing the belt nothing else. So I'm thinking it's either the wrong belt like u said or the alternator has high electrical load because it's only on that belt I'm having issues. I'll let u guys know what I come up with thanks again.
Sounds like its the wrong belt. "V" belts work by gripping the sides of the pulley. The bottom of the belt should never touch the pulley. The squealing is the belt slipping on a pulley, which generates heat and causes the belt to break.
You can verify the problem by looking at one of the broken belts or trying a new belt for just a minute or two of the squealing. The bottom of the belt, should look like new. If its scarred up and melted looking, that it why its breaking.
If so, not sure why you are getting the wrong belt, but if the one you are using is running on the bottom, you need one the same length only one size wider.
There is another possibility, but its less likely. "V" belts come in different tapers. In other words, the angle between the top and bottom of the belt. That angle has to match the angle of the pulleys, so the entire side of the belt comes in contact with the sides of the pulley.
That is less likely, since most of your more common belts are the same.
You can check all this, by taking a new belt, bending it "backwards", in other words, up off the pulley instead of down around it. Slide it down into the pulley, and sight in from the edge.
You should see light under the belt and the sides of the belt should fit snugly on the sides of the pulley.
Also, looking at one of the new broken belts should tell you what the problem is. You should see damage on some part of the belt. If its the bottom the belt is too narrow. If the sides are worn along only one narrow part, its the wrong taper.
If the sides are worn evenly, just melted, you have too much load on the belt. Either a bad bearing or something binding.
If one side is worn more then the other, you have a misaligned pulley.
If the belt is "chewed up", you have a bent or damaged pulley.
Let us know what the belt looks like.
You can verify the problem by looking at one of the broken belts or trying a new belt for just a minute or two of the squealing. The bottom of the belt, should look like new. If its scarred up and melted looking, that it why its breaking.
If so, not sure why you are getting the wrong belt, but if the one you are using is running on the bottom, you need one the same length only one size wider.
There is another possibility, but its less likely. "V" belts come in different tapers. In other words, the angle between the top and bottom of the belt. That angle has to match the angle of the pulleys, so the entire side of the belt comes in contact with the sides of the pulley.
That is less likely, since most of your more common belts are the same.
You can check all this, by taking a new belt, bending it "backwards", in other words, up off the pulley instead of down around it. Slide it down into the pulley, and sight in from the edge.
You should see light under the belt and the sides of the belt should fit snugly on the sides of the pulley.
Also, looking at one of the new broken belts should tell you what the problem is. You should see damage on some part of the belt. If its the bottom the belt is too narrow. If the sides are worn along only one narrow part, its the wrong taper.
If the sides are worn evenly, just melted, you have too much load on the belt. Either a bad bearing or something binding.
If one side is worn more then the other, you have a misaligned pulley.
If the belt is "chewed up", you have a bent or damaged pulley.
Let us know what the belt looks like.
I have a chewed up belt. That was the reason I changed it in the first place. And I checked one of the new belts before it broke and it was missing teeth so to speak.
I'll definitely check the belt for where it being worn when I get home. Thanks for that info. Very helpful, I didn't even think to check all that. This is first time I've had an issue w belts. Usually i just change the belts and I'm good to go lol
So the sides of the belt were worn evenly however I started the vehicle w the belt off and the pulley coming off of the water pump was wobbling a bit. I reved it up real high and started to hear it chirping. The water pump isn't leaking could it still need to be replaced?
Usually one thats worn will leak,if only a slight amount,out of the "weep hole"in the casting,but I've had a few with a good amount of slop in the bearing that didn't leak..
....one way to see if the bearing is loose is to try moving the fan blade by putting your hands on two blades across from each other and pulling/pushing gently and watch to see if the pulley moves,or you feel any play..if you have a clutch fan instead of a solid blade bolted directly to the pump,be aware a bad fan clutch can also feel the same way..(and should be replaced)..
....one way to see if the bearing is loose is to try moving the fan blade by putting your hands on two blades across from each other and pulling/pushing gently and watch to see if the pulley moves,or you feel any play..if you have a clutch fan instead of a solid blade bolted directly to the pump,be aware a bad fan clutch can also feel the same way..(and should be replaced)..
I wiggled it like u said and it does move. Pretty sure it doesn't have clutch fan. So does the movement mean I have to replace the whole water pump? Sorry not that mechanically smart but am to poor to take to a mechanic! This truck is sure teaching me a lot though!
Doing that test with the belt loose or off will make it easier to tell just how much play the bearing has...if it is not leaking it might last a long time the way it is,or fail without much if any warning...the pump is replaced as a unit,you cant install or buy a new bearing for it yourself..
But,the play in the pump might also not be the cause for your belt issues either..
But,the play in the pump might also not be the cause for your belt issues either..
Pump should not have any wiggle in it, ensure it is the pump and not something loose. If it is the pump shaft wobbling that is a problem, although it may not be the only problem. Did you ever eyeball the pulleys real close? Look for un even polished spots, nicks and that there aren't any dents or other abnormalities.
