Sqeal under load - new guy 763.

[carl johansson]

OK everybody, I am lucky enough to have a 763 that i use up here on my property. So it may get used 2 or 3 hours a day for a week, then sit for 3 months. I have developed a loud squeal when it is underload - going up hill for instance, or holding down the bucket petal when it is already maxed out. Less than 20 hours ago I put in a new main belt - the toothed one from the motor to the hydraulic pump. At the same time I put in a new 6715478, from the pump to the fan motor i believe. The Tensioner looks in excellent shape the spring is shiny and new, and it springs back, when you remove the belt. So is it the pulley on that tensioner? or do I need to tighten the main drive belt (it moves up and down about 1/2 inch by hand - seems snug, and toothed I suspect less chance to be slipping. Or am I completely missing the boat and don't have a clue? I am on my way to town - a 50 mile one way trip, so I'm hoping i could get some feedback as to wether I should pick up a new pulley, fan belt, or try some more diagnostics! thanks for all your help Carl Johansson Auberry Ca

 

[OldMachinist]

It sounds like the drive belt is slipping(main belt).

 

[carl johansson]

It sounds like the drive belt is slipping(main belt).

thanks OM Machinist, but i'm not following that. If i raise the drive idler that releases tension, I am guessing my drive tensioner may be tango uniform? I took 2 photos and resized them, but I cannot figure out how to post them here. But the peg that fits into the smile slot on the lower back side of the idler, - that is all the way to the rear of the unit, and the pointer up front is past the peg, at the back side of the spring coil. The thing spins freely, no grabbing wobbling or groaning - but raising the idler will defintely release tension, not add it. I will try to put the photos on a website and give you a link so you can take a look. Carl Johansson

 

[carl johansson]

thanks OM Machinist, but i'm not following that. If i raise the drive idler that releases tension, I am guessing my drive tensioner may be tango uniform? I took 2 photos and resized them, but I cannot figure out how to post them here. But the peg that fits into the smile slot on the lower back side of the idler, - that is all the way to the rear of the unit, and the pointer up front is past the peg, at the back side of the spring coil. The thing spins freely, no grabbing wobbling or groaning - but raising the idler will defintely release tension, not add it. I will try to put the photos on a website and give you a link so you can take a look. Carl Johansson

Ok I can't figure out how to edit, and after i post a photo, then backtrack to get another one - the post I am composing goes away, so i will post 2X here, a photo in each

This is the front of the idler arm, you can see that the pointer is all the way at the rear of the post that holds the spring

 

[carl johansson]

Ok I can't figure out how to edit, and after i post a photo, then backtrack to get another one - the post I am composing goes away, so i will post 2X here, a photo in each

This is the front of the idler arm, you can see that the pointer is all the way at the rear of the post that holds the spring

Ok this is the rear of the idler arm, I cleaned it up a bit to make it easier to see. you can see the post is all the way at the end of the slot. The rear of the bobcat would be toward the bottom of the photo

So anyone help me out here? am i completely clueless, or is the thing in fact Tango Uniform, and needs replacement?
Carl Johansson
Auberry ca

 

[Tazza]

Ok this is the rear of the idler arm, I cleaned it up a bit to make it easier to see. you can see the post is all the way at the end of the slot. The rear of the bobcat would be toward the bottom of the photo

So anyone help me out here? am i completely clueless, or is the thing in fact Tango Uniform, and needs replacement?
Carl Johansson
Auberry ca

There are different style idlers, one has a pointer so you know how tight it is, the other you are meant to use a tension wrench and a bar, or something like that. X movement gives the set tension.
There should be a long bolt attached to the top of the idler assembily that when you tighten the nut on the under side it, pulls the belt tight. As you don't have the tensioning tool tighten up up as tight as you think is about right, if it squeels do it a little more.
Your idler looks spring loaded, but i can't see the pointer. Mine broke off, but i managed to weld a new one to it.
Remember to do up the lock nut! or it will rattle loose.

 

[carl johansson]

There are different style idlers, one has a pointer so you know how tight it is, the other you are meant to use a tension wrench and a bar, or something like that. X movement gives the set tension.
There should be a long bolt attached to the top of the idler assembily that when you tighten the nut on the under side it, pulls the belt tight. As you don't have the tensioning tool tighten up up as tight as you think is about right, if it squeels do it a little more.
Your idler looks spring loaded, but i can't see the pointer. Mine broke off, but i managed to weld a new one to it.
Remember to do up the lock nut! or it will rattle loose.

The idler has a coiled spring inside it. It has a pointer, if you look closely at the photo you can see it alighned with the back side of the coil spring mounting post. I do not however have any bolt that moves the unit up or down. The only bolt is the bolt that mounts the plate to the bobcat. The plate has a slotted mount, so you can move it up or down, but I have no idea what the spring is supposed to do, I will go down to the dealer ansd see what a new unit looks like, maybe I can figure it out from that!

 

[jerry]

The idler has a coiled spring inside it. It has a pointer, if you look closely at the photo you can see it alighned with the back side of the coil spring mounting post. I do not however have any bolt that moves the unit up or down. The only bolt is the bolt that mounts the plate to the bobcat. The plate has a slotted mount, so you can move it up or down, but I have no idea what the spring is supposed to do, I will go down to the dealer ansd see what a new unit looks like, maybe I can figure it out from that!

Is it possible that the belt routing is not correct and idler should be on the other side of belt? I have done that on autos.

 

[Tazza]

Is it possible that the belt routing is not correct and idler should be on the other side of belt? I have done that on autos.

Is there a threaded hole in the end of the plate? There should be a long piece of threaded rod that you use to hold it on place and lock it down with the other bolt you mention..... It should be on the opposite end to the long slot. Its possible the previous owner brok it or something?
Good to hear it has a pointer, you can set the correct tension that way.

 

[Rojas]

The idler has a coiled spring inside it. It has a pointer, if you look closely at the photo you can see it alighned with the back side of the coil spring mounting post. I do not however have any bolt that moves the unit up or down. The only bolt is the bolt that mounts the plate to the bobcat. The plate has a slotted mount, so you can move it up or down, but I have no idea what the spring is supposed to do, I will go down to the dealer ansd see what a new unit looks like, maybe I can figure it out from that!

If you look at the picture that old machinist posted you'll note they are using a lever between the bracket and housing to pry the bracket downward and compress the spring.

 

[carl johansson]

If you look at the picture that old machinist posted you'll note they are using a lever between the bracket and housing to pry the bracket downward and compress the spring.

Thanks guys,
that was it. I don't have the bolt adjusted tensioner. on my setup You take a pry bar, put it in the notch of the fan belt housing and pry on the top of the mounting plate. as you “reload” the spring it makes a clicking sound, then you make sure the pointer is not past the 3 o clock position (Ie like 2 or 2:30 is good), then just tighten up the mounting bolt. ingenius, and simple, once you figure it out! Thanks for all the help guys!