Bobcat 763 overheating from loose belt - tensioner very stiff

[mini]

I found my overheating issue today, it appears to be a stiff belt tensioner, on the fan belt, the belt is almost fall off loose, I pulled out the battery and the plastic cover from the side of the engine, to take a look, I pulled back the tensioner temporarily, to tighten the belt, and it now blows a lot more air thru the sides, no overheating but I have to do something with this belt tensioner/idler it's so stiff no spring action at all should the tensioner be replaced? or can I fix it? is it hard to remove, ? any help would be very helpful Thanks Mini

 

[Tazza]

I think it's not too bad to remove, one bolt, that is what it pivots on. So get it out and free it up and hopefully you will be all set.
The only issue that does happen, is the bearing in the pulley can lock up and allow the belt to drag across it and it just falls apart. When it's out, you can test all that.

 

[bobbie-g]

I think it's not too bad to remove, one bolt, that is what it pivots on. So get it out and free it up and hopefully you will be all set.
The only issue that does happen, is the bearing in the pulley can lock up and allow the belt to drag across it and it just falls apart. When it's out, you can test all that.

Well, Tazza is a lot better at this stuff than I am! I've worked on the fan belt tensioners on several machines, and I find them somewhat difficult to access. I've even thought about drilling a hole in the side of the Bobcat at times! At any rate, my notes say the pulley on the tensioner arm requires a 5/16" hex key to remove. The swinging tensioner arm requires a 1/4" hex wrench. Be really careful to fully seat the hex wrenches before yanking hard on them, the last thing you want to do is round out the bolt. There is a bushing inside the tensioner arm which I always replace, as well as the spring. I've heard the spring can get weak, letting the belt slip. And I always replace the belt if I remove the tensioner arm, just because I don't wanna get back in there again soon. Here's my first attempt at posting a pix on this forum: https://www.dropbox.com/s/kvr2srljwn8y2s2/Bobcat_763_fanbelt_tensioner_arm.jpg?dl=0 ---Bobbie G

 

[mini]

Well, Tazza is a lot better at this stuff than I am! I've worked on the fan belt tensioners on several machines, and I find them somewhat difficult to access. I've even thought about drilling a hole in the side of the Bobcat at times! At any rate, my notes say the pulley on the tensioner arm requires a 5/16" hex key to remove. The swinging tensioner arm requires a 1/4" hex wrench. Be really careful to fully seat the hex wrenches before yanking hard on them, the last thing you want to do is round out the bolt. There is a bushing inside the tensioner arm which I always replace, as well as the spring. I've heard the spring can get weak, letting the belt slip. And I always replace the belt if I remove the tensioner arm, just because I don't wanna get back in there again soon. Here's my first attempt at posting a pix on this forum: https://www.dropbox.com/s/kvr2srljwn8y2s2/Bobcat_763_fanbelt_tensioner_arm.jpg?dl=0 ---Bobbie G

Thanks tazza / bobbie , When I looked at this more closely today, I now can see the main swivel bolt is totally seized in the aluminum arm, and the movement I am getting must be just the screw unthreading and threading back on, I sprayed some lube on it, but it's seized very tight, not sure how it could be seized, if there is a bushing inside, yes it is a bit of a tight spot, , all I know is this needs to be fixed, before I use it , I can't afford to overheat this engine, again

 

[mini]

Update: A day later and I Finally got the tensioner off, wow I can't believe how seized it was, for a plastic bushing, (was considering replacing the plastic bush with a bronze bushing) but I decided to just ream thru the plastic bushing with a 1/2" reamer to clean it out, and polished the pin, added some grease, and re-assembled, seems good enough , as it moves with spring pressure now, and the belt is tight, and no more overheating, which is a scary engine destroying sight and sound hearing the coolant boil, and watching it blow out tons of steam. Thanks for the help, Tazza and Bobbie and thanks for posting that photo of the arm with the pulley removed, it helped me a lot to show me how to reassemble it back with preload on the spring, and overall saved me money and time.

 

[bobbie-g]

Update: A day later and I Finally got the tensioner off, wow I can't believe how seized it was, for a plastic bushing, (was considering replacing the plastic bush with a bronze bushing) but I decided to just ream thru the plastic bushing with a 1/2" reamer to clean it out, and polished the pin, added some grease, and re-assembled, seems good enough , as it moves with spring pressure now, and the belt is tight, and no more overheating, which is a scary engine destroying sight and sound hearing the coolant boil, and watching it blow out tons of steam. Thanks for the help, Tazza and Bobbie and thanks for posting that photo of the arm with the pulley removed, it helped me a lot to show me how to reassemble it back with preload on the spring, and overall saved me money and time.

And thanks for the feedback! Problem solutions are what makes the forum here so worthwhile. --- I still don't have the hang of posting a pix. My problem may be in trying to use Dropbox. ---Bobbie G

 

[Tazza]

And thanks for the feedback! Problem solutions are what makes the forum here so worthwhile. --- I still don't have the hang of posting a pix. My problem may be in trying to use Dropbox. ---Bobbie G

Good to hear you got it off and back on again.
Drop box seems to be very fussy for me. I loaded your image in firefox, but IE refused to play *shrug* no idea why.