1999 Yamaha Wolverine rear output shaft seal leak

[tssetmr]

I replaced the rear output shaft seal a year ago and it's leaking badly again. They are a pain to do because of the yoke being bolted to the shaft and the nut behind it. Has anybody seen this happen routinely to know if there may be something contributing to it like a bushing worn out on the output shaft that allows play? Also, any helpful hints as to how to get the nut off easier? Thank you.

[Ajmboy]

I have not seen this, but I can tell you that with automotive seals, even the slightest imperfection can cause a seal to go bad.

[swampcat07]

Make sure the shaft does not have any up and down/ side to side play. That can mean a warn bearing. Also take some steel wool and clean the surface of the shaft where the seal meets with the shaft to remove any sharp material. Just lightly you do not want to reduce the od of the shaft. Also if the fluid heats up a lot the fluid can be forced past the seal. Make sure the vent line to the rear diff is also open (if there is one) to alleviate any pressure.