Bobcat S300 Thumping noise

[rnbuck01]

I've got a Bobcat S300 and it sounds like it's making a thumping noise when you drive it. I jacked up the machine and tried to run the machine to hear it but it didn't do it in the air. I took the two lower side covers off and had someone walk beside me and they felt a vibration on the side above the drive motor. It only does it when you are driving it and it does it worse when you are turning the machine. Tested the wheel bearings on all 4 axles and they were all tight. Removed front Chaincase cover and both sprockets were tight . Has anyone have this problem?

 

[brdgbldr]

Do the chains have a lot of slop in them? A stretched out chain can be loose enough to "slap" the chain case. The chain could be skipping on any one of the sprockets. I would try to do a good inspection of the sprockets to see if they are worn or even missing a tooth. I don't have a S300 but my Bobcat has 4 axle sprockets and two double drive sprockets any one could be the culprit. That is where I would start.

 

[OldMachinist]

Do the chains have a lot of slop in them? A stretched out chain can be loose enough to "slap" the chain case. The chain could be skipping on any one of the sprockets. I would try to do a good inspection of the sprockets to see if they are worn or even missing a tooth. I don't have a S300 but my Bobcat has 4 axle sprockets and two double drive sprockets any one could be the culprit. That is where I would start.

I assume you've checked for a loose wheel.
Does the thump seem to be in sync with tire rotation or is it random?

 

[rnbuck01]

I assume you've checked for a loose wheel.
Does the thump seem to be in sync with tire rotation or is it random?

Yeah I've checked for a loose wheel and the wheel bearings. Someone was outside and they marked the tire and each revolution it made the noise. It does it more when your steering.

 

[OldMachinist]

Yeah I've checked for a loose wheel and the wheel bearings. Someone was outside and they marked the tire and each revolution it made the noise. It does it more when your steering.

Could still be a bad bearing even thou it doesn't have any play in it. I'd still have another look at the sprockets before tearing into the axles.
Although its a long shot you could also temporarily swap the tires from one side to the other and see if the noise follows them.

 

[rnbuck01]

Could still be a bad bearing even thou it doesn't have any play in it. I'd still have another look at the sprockets before tearing into the axles.
Although its a long shot you could also temporarily swap the tires from one side to the other and see if the noise follows them.

I jacked up the machine and removed the front and middle Chaincase covers, raised up the cab. I ran the machine forward and reverse and got a camera down inside there and didn't see any thing busted off. I noticed the tire moving close to an inch up in the air. what is it suppose to? I rock the tire front to back and it makes a thump when you do that, not every time. I tried to see if any other tires are doing it but it is just the one tire and it is the left rear tire. I know the tire is moving close to an inch, but do you think this is the problem that the chain is too loose and making the thumping with the sprocket worn and the chain worn making the thumping noise like you rotate it and it's hitting something solid. Does it usually do something when the chains are too loose?

 

[OldMachinist]

I jacked up the machine and removed the front and middle Chaincase covers, raised up the cab. I ran the machine forward and reverse and got a camera down inside there and didn't see any thing busted off. I noticed the tire moving close to an inch up in the air. what is it suppose to? I rock the tire front to back and it makes a thump when you do that, not every time. I tried to see if any other tires are doing it but it is just the one tire and it is the left rear tire. I know the tire is moving close to an inch, but do you think this is the problem that the chain is too loose and making the thumping with the sprocket worn and the chain worn making the thumping noise like you rotate it and it's hitting something solid. Does it usually do something when the chains are too loose?

Is the axle hub also moving up and down or just the circumference of the tire?
If the hub is also moving then the axle may be bent and it's binding as it goes around.

 

[rnbuck01]

Is the axle hub also moving up and down or just the circumference of the tire?
If the hub is also moving then the axle may be bent and it's binding as it goes around.

It's hard to tell. It doesn't do it every time. There is no movement of the hub or tire when I try to move it up and down.

 

[rnbuck01]

Is the axle hub also moving up and down or just the circumference of the tire?
If the hub is also moving then the axle may be bent and it's binding as it goes around.

I try to move the tire up and down and it don't move at all. Tire is just turning and you go back and forth there sound like a klunk in the axle tube.

 

[antfarmer2]

I try to move the tire up and down and it don't move at all. Tire is just turning and you go back and forth there sound like a klunk in the axle tube.

If it moves in and out it is a bad bearing or a loose hub hope for the hub

 

[rnbuck01]

If it moves in and out it is a bad bearing or a loose hub hope for the hub

Where can I buy chains and sprockets online?

 

[Tazza]

Where can I buy chains and sprockets online?

A bearing or wire rops supply shop should be able to get chain and master link(s) if needed.
I got mine in boxes of 10'