Lower main seal leakage in YT6800

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Lower main seal leakage in YT6800

amuller
Apparently this is a common problem.  Hoping somebody can fill me in on what causes it before I get into a repair.

Apparently these engines have plain bearings, and there is a lot of belt pull in one direction, so I'm wondering if the bearings wear and the shaft moves?   Or is it just the seal itself that goes bad?

And anybody have the dimensions of the seal handy?

Any advice appreciated.

Alan
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Re: Lower main seal leakage in YT6800

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I have a y t6700 and a yt 6800 , had to replace the seals in both just last year. the heat just cooks the seals over time. just replace the seal and you will be fine. Get a oem seal from Yamaha is what I used.
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Re: Lower main seal leakage in YT6800

amuller
Thanks for the info!  How did you get at the seal?  Did you pull the engine?  Is the pulley/clutch hard to get off?

Thanks.
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Re: Lower main seal leakage in YT6800

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pulled clutch and pulley off removed engine , then replace seal. You need to have a special puller to get the pulley off. do a search on here there is a post on how to make a puller using a bolt and a spacer rod. to get pulley off.
DW
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Re: Lower main seal leakage in YT6800

DW
on my 6800 i did not remove the engine. removed pto then pulley. installed seal then reassembled pulley and pto. hardest part was removing the pulley. with good pulley tools and common sense it's not that hard. it's also a good idea to have the pto rebuilt. 2fastforyou on this site can do that very well.   Denny
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Re: Lower main seal leakage in YT6800

Alan
Thanks.

Somebody mentioned turning the tractor on it's side and that seems reasonable.  

When you mention "rebuilding" the PTO, what does that amount to, specifically?

I haven't really investigated, but it looks to me as if the engine has oil leaks from more than the bottom seal.  Are there other common leak points?

Thanks again!

Alan
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Re: Lower main seal leakage in YT6800

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Pto clutch usualy works till the drive rivets shear off or megnatic coil burns out. I had one engine that was leaking where the two engine block haves went together.
DW
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Re: Lower main seal leakage in YT6800

DW
In reply to this post by amuller
i used a pretty big chisel that was tapered and used it as a pickel fork and hammered it between the pulley and the metal part on the case. did not have to remove engine. just spin the pulley around in several places and smack it between the pulley and bottom case. you will see a metal part on the bottom of the case and thats where you should place the chisel. you should e-mail 2fast4u on this site and ask about rebuilding your pto. he modifies them which makes them better. was only a hundred bucks which is much cheaper than a new one and you have the original one that came with for a perfect fit.