Crankshaft Oil Seal Installation Issue

bertsmobile1

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.076" is WAY too much press fit.

You've got the wrong seal.

Yes You have the wrong oil seal
Oil seals should be a class IV transitional fit or a class V interfearence fit
A type IV should be able to be fitted with finger pressure or a light mallet
A type V should be able to be fitted with a "Light Press" or heavy mallet.

Oil seals should be around these tightnesses
https://www.engineersedge.com/class_iv.htm

GO down the table and for the seal diameter of around 2.5" your crush should be between 0.0002" to 0.0024" .

This is a tad looser than the measured 0.067"
With oil seals , the crush is generally the thickness of the rubber that coats the steel case so removing & replacing it will not damage the hole ( in theory ).
 

Scrubcadet10

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I searched on the internet and found several photos of sumps with the same part number and they all appear to be identical to the one I have. Of course, there could be a difference in the diameter of the opening.
If the hole was a different size it would be a different part number
 

firedawgsatx

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Yes You have the wrong oil seal
Oil seals should be a class IV transitional fit or a class V interfearence fit
A type IV should be able to be fitted with finger pressure or a light mallet
A type V should be able to be fitted with a "Light Press" or heavy mallet.

Oil seals should be around these tightnesses
https://www.engineersedge.com/class_iv.htm

GO down the table and for the seal diameter of around 2.5" your crush should be between 0.0002" to 0.0024" .

This is a tad looser than the measured 0.067"
With oil seals , the crush is generally the thickness of the rubber that coats the steel case so removing & replacing it will not damage the hole ( in theory ).

Yes, it does appear the seal I was sent a genuine B & S 399781S is not the correct seal for the sump. It is neither a class IV or class V fit.
 

firedawgsatx

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If the hole was a different size it would be a different part number

That is what i figured to be true. While searching for photos of the sump on the internet there appears to be two different versions of the sump with part number 498983. They look extremely close in appearance except for a slight variation of the pattern of the casting on the exterior side and one version has a collar around the opening and the other version does not. My sump is the one with the collar.
 
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Scrubcadet10

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I would email or call Briggs with your model and code date numbers.
They should tell you
 

bertsmobile1

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You have already measured the hole diameter and shaft diameter so just measure the thickness and order a new oil seal from a bearing supply shop.
All seals used on mowers are a common size.
They have to be in order to reduce costs.
Just go to a real bearing store and not some fly by night online shop flogging junk from 3rd world countries.
 

firedawgsatx

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I would email or call Briggs with your model and code date numbers.
They should tell you

Thanks for the suggestion. I will contact Briggs to see if they can assist me. I will post what they tell me.
 

firedawgsatx

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You have already measured the hole diameter and shaft diameter so just measure the thickness and order a new oil seal from a bearing supply shop.
All seals used on mowers are a common size.
They have to be in order to reduce costs.
Just go to a real bearing store and not some fly by night online shop flogging junk from 3rd world countries.


Thanks for the info!
 

bertsmobile1

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I am a small fry and independent so all of my oil seals are in the oil seal box
Thus you walk in and ask for an oil seal I ask have you got the old one then match it with what I have in the box.
Mr big multi franchise usually has no oil seals and orders them in as required.
If they do they are in bins according to the size of the part for most efficient storage so unless the computer gives them a bin number they can not find a suitable match.

My parts suppliers only carry a very limited range so I get most of them from an engineering supply company.
A pack of 10 is about the same price as 3 single so I usually get a pack.
 
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