Drive Belt Breaks repeatedly

[conc2steel]

I have a Bobcat 853 and recently had the drivebelt break while moving some dirt. The broken belt was wrapped around the hydraulics pully in this proccess which you can read about in a previous post. With less than 4 hours on a new 4V belt, the same thing has occured : when skid steer came under load with the bucket full ................ the belt broke AND wrapped around the hydraulics pully. DOES ANYONE HAVE ANY IDEA WHAT COULD BE CAUSING THIS?

 

[Fishfiles]

First thought , improper adjustment of belt , possiblly a bad belt idler , maybe a bad bearing on the input shaft of the sunstrand causing the pulley to wobble , also I would look at the motor/pump mounts as the whole motor may be moving around , I would also check the condition of the pump pulley

 

[perry]

First thought , improper adjustment of belt , possiblly a bad belt idler , maybe a bad bearing on the input shaft of the sunstrand causing the pulley to wobble , also I would look at the motor/pump mounts as the whole motor may be moving around , I would also check the condition of the pump pulley

You probably don't want to hear this but, I would pull the engine/ hydrostatic assy. After conferring with a BC mechanic, I pulled mine in two hours. Not only can you find/fix problem, you can check and replace other items. Exhaust manifolds have been a problem on most all vehicles, I loosened and applied anti-freeze for any future repairs, replace all radiator hoses, replaced fuel tank sender plus all hoses and finally the drive belt. Even with it setting on an old tire, installing the drive belt was not all that easy.

 

[Fishfiles]

You probably don't want to hear this but, I would pull the engine/ hydrostatic assy. After conferring with a BC mechanic, I pulled mine in two hours. Not only can you find/fix problem, you can check and replace other items. Exhaust manifolds have been a problem on most all vehicles, I loosened and applied anti-freeze for any future repairs, replace all radiator hoses, replaced fuel tank sender plus all hoses and finally the drive belt. Even with it setting on an old tire, installing the drive belt was not all that easy.

Anti sieze ? whats on the menu for the games today Perry , we are having Marguaritas with Jose Cuvero , on two by three I be thinking Drew Brees

 

[TriHonu]

You probably don't want to hear this but, I would pull the engine/ hydrostatic assy. After conferring with a BC mechanic, I pulled mine in two hours. Not only can you find/fix problem, you can check and replace other items. Exhaust manifolds have been a problem on most all vehicles, I loosened and applied anti-freeze for any future repairs, replace all radiator hoses, replaced fuel tank sender plus all hoses and finally the drive belt. Even with it setting on an old tire, installing the drive belt was not all that easy.

We feel your pain... Fishfiles is on the money.
Can you get a good look at the belt and the area of the break? Does it show excessive wear on the drive surface or the back of the belt? The belt damage could help lead you to the problem.
A spontaneous break on a new belt could come from running it too tight and tearing the web layers in the belt. Did you turn the pulleys and make sure the grooves were clean and no remnants of the last belt were stuck on the pulley?
If you see excessive wear on the drive surface either the belt was not tight enough or you have excessive resistance in the Hydrostatic/Hydraulic pump or the pulleys are worn and not gripping the belt properly.
If you have wear on the back of the belt you idler may have a bearing that froze after it got warm enough.
You could have got a defective belt.
I would get a good light and mirror and do a careful inspection. When you get the belt out I would also check the pump drive pulley for run-out. Maybe the shaft bent when the previous belt jammed?
Pulling the engine and pumps is a project. I wouldn't pull them unless absolutely necessary.
My .02 worth.

 

[perry]

We feel your pain... Fishfiles is on the money.
Can you get a good look at the belt and the area of the break? Does it show excessive wear on the drive surface or the back of the belt? The belt damage could help lead you to the problem.
A spontaneous break on a new belt could come from running it too tight and tearing the web layers in the belt. Did you turn the pulleys and make sure the grooves were clean and no remnants of the last belt were stuck on the pulley?
If you see excessive wear on the drive surface either the belt was not tight enough or you have excessive resistance in the Hydrostatic/Hydraulic pump or the pulleys are worn and not gripping the belt properly.
If you have wear on the back of the belt you idler may have a bearing that froze after it got warm enough.
You could have got a defective belt.
I would get a good light and mirror and do a careful inspection. When you get the belt out I would also check the pump drive pulley for run-out. Maybe the shaft bent when the previous belt jammed?
Pulling the engine and pumps is a project. I wouldn't pull them unless absolutely necessary.
My .02 worth.

Anti-freeze!!!, dang..I gotta go light on the tequila.....

 

[perry]

Anti-freeze!!!, dang..I gotta go light on the tequila.....

I was a little apprehensive about pulling it out, until it was out!..no big deal. A good project for the winter.
I didn't make the engine removal tool pictured in the manual, just fabricated a simple piece that fits on my old engine hoist. If you want a picture let me know....

 

[Tazza]

I was a little apprehensive about pulling it out, until it was out!..no big deal. A good project for the winter.
I didn't make the engine removal tool pictured in the manual, just fabricated a simple piece that fits on my old engine hoist. If you want a picture let me know....

I wouldn't mind a picture, my 751 i know is not the same, but it would give me a good idea on it all. I had plans on making essentially a small fork lift that bolts to the engine with legs under the machine with a hydraulic jack to lift the engine and pump then roll it back and out. That of course never happened!

 

[Fishfiles]

I wouldn't mind a picture, my 751 i know is not the same, but it would give me a good idea on it all. I had plans on making essentially a small fork lift that bolts to the engine with legs under the machine with a hydraulic jack to lift the engine and pump then roll it back and out. That of course never happened!

I did an 853 about two moths ago , I uses a set of Bobcat forks which I took one fork off and a piece of 5/16 chain and two 5/16 shackles , there were two lifting eyes on the head of the motor , streched the chains as tight as I could get it across the two eyes , slide the fork in as far as possible and tilted up , easy in and out

 

[Tazza]

I did an 853 about two moths ago , I uses a set of Bobcat forks which I took one fork off and a piece of 5/16 chain and two 5/16 shackles , there were two lifting eyes on the head of the motor , streched the chains as tight as I could get it across the two eyes , slide the fork in as far as possible and tilted up , easy in and out

I managed to remove mine with a chain off the end of my bucket, easy enough to remove but i know it won't go in like that!. I like for fork idea though..... I need to get to work on making my backing plate for the forks i have here.

 

[Fishfiles]

I managed to remove mine with a chain off the end of my bucket, easy enough to remove but i know it won't go in like that!. I like for fork idea though..... I need to get to work on making my backing plate for the forks i have here.

When you make your forks , make them like OEM , so that the indivual forks can be removed , it comes in very handy to have only one fork , two forks get i the way on alot of jobs , putting motors works well like this but what is really impressive is changing out or installing tracks , the one fork setup allows me to change a track on a T series by myself in about 10-15 minutes per side start to finished , that is using a air grease gun to pump them bck up s that takes the longest time , if you blow a hole in the end of the fork , you can use the hole to put over the steel guide that sticks up out the rubber of the track and slide the tracks right off under the rear roller first , also I use the fork to push in on the idler after releasing the grease pressure

 

[perry]

When you make your forks , make them like OEM , so that the indivual forks can be removed , it comes in very handy to have only one fork , two forks get i the way on alot of jobs , putting motors works well like this but what is really impressive is changing out or installing tracks , the one fork setup allows me to change a track on a T series by myself in about 10-15 minutes per side start to finished , that is using a air grease gun to pump them bck up s that takes the longest time , if you blow a hole in the end of the fork , you can use the hole to put over the steel guide that sticks up out the rubber of the track and slide the tracks right off under the rear roller first , also I use the fork to push in on the idler after releasing the grease pressure

What makes it easy to pull are the motor/drive mounts, lift just enough to take the pressure off, pull the mounts and your out. Fish is correct on the lift chain, make it as tight as possible.
One other thing you need to be careful with is the fuel level sender, if your not careful you will 'break' it off on re-installing. I placed a piece of angle iron on top of the fuel tank next to the sending unit. Doing this and another set of hands will make it simple.
Use masking tape and mark each electrical connection, most will only go one way but do it just in case.
I followed instructions but could not post pictures of engine lift tool. The paste function was not highlighted???. Suggestions please......

 

[perry]

What makes it easy to pull are the motor/drive mounts, lift just enough to take the pressure off, pull the mounts and your out. Fish is correct on the lift chain, make it as tight as possible.
One other thing you need to be careful with is the fuel level sender, if your not careful you will 'break' it off on re-installing. I placed a piece of angle iron on top of the fuel tank next to the sending unit. Doing this and another set of hands will make it simple.
Use masking tape and mark each electrical connection, most will only go one way but do it just in case.
I followed instructions but could not post pictures of engine lift tool. The paste function was not highlighted???. Suggestions please......

One more thing, I attached a ratchet tie down to the engine hoist and the other end to the hydrastatic drive, you will need to ratchet up the drive to make the engine and drive level.

 

[Tazza]

One more thing, I attached a ratchet tie down to the engine hoist and the other end to the hydrastatic drive, you will need to ratchet up the drive to make the engine and drive level.

The carrage i have allows me to remove the tynes off the side. I was going to drill or burn a hole on the ends to allow me to secure chains. The ratchet strap is a good idea too.
I'm no expert on posting pictures here, but just load the hosted picture, copy then paste it here works for me using IE, i believer it has issues with other web browsers.

 

[perry]

The carrage i have allows me to remove the tynes off the side. I was going to drill or burn a hole on the ends to allow me to secure chains. The ratchet strap is a good idea too.
I'm no expert on posting pictures here, but just load the hosted picture, copy then paste it here works for me using IE, i believer it has issues with other web browsers.

I have a photo resizer but it won't go lower than 320x320. I'll look around for another photo resizer. Unless you guys know of one???.

 

[Tazza]

I have a photo resizer but it won't go lower than 320x320. I'll look around for another photo resizer. Unless you guys know of one???.

I just use photoshop. There was another freeware one, but i can't remember its name...

 

[TriHonu]

I just use photoshop. There was another freeware one, but i can't remember its name...

I use IrfanView. You can download it from their website:
http://www.irfanview.com/

 

[perry]

I use IrfanView. You can download it from their website:
http://www.irfanview.com/

Tazza, here is a pic of my homemade engine puller, it must tilt up to fit in the engine compartment. I welded a nut on top of the 2x2 to make it angle up.


http://s170.photobucket.com/albums/u253/perrynboo/?action=view&current=007.jpg

 

[perry]

Tazza, here is a pic of my homemade engine puller, it must tilt up to fit in the engine compartment. I welded a nut on top of the 2x2 to make it angle up.


http://s170.photobucket.com/albums/u253/perrynboo/?action=view&current=007.jpg

Oh yeah!, the V-cut is because I made the chain very tight and It will not slip off.....