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Bushing between pto bearing and case?

Shibby

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Is this bushing replaceable or does the whole case half need to be replaced? There is a lot of play and it rotates between the case and bearing, so maybe the bushing it worn from both sides? If the case is worn are there over sized bushings to keep the casing? It's an original Stihl case so I'd prefer to not get aftermarket if I can help it.
 

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Al Smith

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Nothing is impossible but it might not be the best option to attempt to make a new insert .Now that said although I've never work on those conditions is internally within the insert is knurling the metal to give it a tight fit .You can do it with a prick punch then use something like "Quick metal press fit "compound using the classic heat ,freeze assembly method .It's worked for me in the past with spun main bearings in aluminum alloy cases and as far as I know there haven't been any failures .
 

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Nothing is impossible but it might not be the best option to attempt to make a new insert .Now that said although I've never work on those conditions is internally within the insert is knurling the metal to give it a tight fit .You can do it with a prick punch then use something like "Quick metal press fit "compound using the classic heat ,freeze assembly method .It's worked for me in the past with spun main bearings in aluminum alloy cases and as far as I know there haven't been any failures .

This is usually a situation where the steel insert that the bearing fits into becomes loose in the case.
 

Al Smith

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Now this I don't know however as a guess it might be possible to use the same method to shrink the case which is softer than the insert .This is an old tool and die makers trick on machine bearings which usually is cast iron .I imagine you'd need to heat the case and pop out the insert then dimple the hole and drive it back in using heat shrink compound . It would be worth a try because he's got nothing to lose as it isn't in the best usable condition as it is .Nothing ventured nothing gained thing :)
 

Shibby

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It's currently not usable since it makes a vacuum leak around the bushing, so I'm willing to try whatever. Worst situation is getting a 660 clone case and put all the original Stihl stuff back on it.

I'm not sure how those bushings are in there. It spins freely, and the case has a lip on the outside to stop it from coming out, but what is stopping it from falling to the inside? The case is pretty worn out, which I why I asked if an oversized bushing may work if I machined the hole larger and back to round.

The bearing itself was still good, so I think this bushing just spun once and then wore itself a larger hole until the saw quit running.
 

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It's currently not usable since it makes a vacuum leak around the bushing, so I'm willing to try whatever. Worst situation is getting a 660 clone case and put all the original Stihl stuff back on it.

I'm not sure how those bushings are in there. It spins freely, and the case has a lip on the outside to stop it from coming out, but what is stopping it from falling to the inside? The case is pretty worn out, which I why I asked if an oversized bushing may work if I machined the hole larger and back to round.

The bearing itself was still good, so I think this bushing just spun once and then wore itself a larger hole until the saw quit running.

That sleeve is cast into the case half when it's made. I don't think you will have any luck fixing it.....at least not without doing more work than it's worth by a long shot. I'd get an aftermarket case. They ain't terrible.
 

Al Smith

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It would not be a thing just anybody could do without the now how plus the machinery to do it .To have a sleeve custom made and installed at a machine shop would cost more than the entire saw is worth most likely .If it were my own saw I'd have to give it a try .It's just the way I am . If it belonged to somebody else I would not .
 

gurwald

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If you have the tools its possible, I have done similar repairs on old electric motors where the bearing spun in the housing. Turn the bearing pocket in the housing, make a new press fit sleeve, add some loctite and press it in, then turn the inner diameter to the right size. But it would be harder to chuck a case half in the lathe. o_O
But I imagine it would cost more to have someone else do it than to find a new oem case.
 

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Sorry to derail. The MS660(OEM 2012 made) I split doesn't have that bushing? Neither do the clone case.
 

Shibby

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Bought an aftermarket case. If nothing else I have a backup flywheel side case half.
 
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