replacing engine rear main seal

Sun Aug 25, 2013 9:30 pm

i have a cub in my shop with a really badly leaking rear main engine seal. It is leaking so badly that after an hours run time it will fill the trough across the front of this flail, and the flywheel is throwing enough oil into the front of the starter that it is running out the opposite end.
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I already have one of Tim's rebuilt retainers and got it ready to split today, so I hope to get it finished tomorrow. it is good to for once be working on a cub with only one problem, and no stuck or rusted bolts. It is bad that it is my cub.

Re: replacing engine rear main seal

Mon Aug 26, 2013 5:31 am

John, enjoy the day and I know you will, those bolts come out pretty easy with that little impact DeWalt you carry. Just be careful and not break anything while you're in the process. Is splitting a cub anything like taking the hood off ? -- your gonna find something else to fix.

Re: replacing engine rear main seal

Mon Aug 26, 2013 6:09 am

Good luck John :D :D Have fun...Dave

Re: replacing engine rear main seal

Mon Aug 26, 2013 7:24 am

I feel your pain. I am also in the same boat with a rebuilt retainer on my 184. Loses about a cup of oil per mowing hour through the rear seal.

Are you going to just replace the seal again or do you think there is another issue causing this? I am starting to think that ring blowby pushes the oil through the seal.

What rear seal part number are you going to get now that your retainer has been machined?

Re: replacing engine rear main seal

Mon Aug 26, 2013 8:07 am

Tim (tst) presses in the new seal that is the correct fit after he flattens and enlarges the seal opening.

Bob

Re: replacing engine rear main seal

Mon Aug 26, 2013 8:58 am

randallc wrote:.......Is splitting a cub anything like taking the hood off ? -- your gonna find something else to fix.
Hopefully not, this is the same one we changed the transmission input shaft in at MidMo, so there should not be much to do other than maybe oiling the generator while the hood is off.

outdoors4evr wrote:........
Are you going to just replace the seal again or do you think there is another issue causing this? I am starting to think that ring blowby pushes the oil through the seal........
When I rebuilt the engien about 3 r so years ago I simply reused the original retainer and staked the seal in with a little sealer around it. It has held till now, but this time I ordered one of Tim's rebuilt retainers. He straightens them if needed, and Helicoils the lower holes if needed, plus cuts it out for a bigger seal and presses it in. I have used the ones Rick used to rebuild, and also Tim's before, and they do a good job of solving the oil leak problem. One note, if the old seal has worn a groove where it runs on the crankshaft you may need to smooth that up some to prevent more leaking.

Re: replacing engine rear main seal

Mon Aug 26, 2013 7:50 pm

Hi John, It will be nice to have a fairly fixed up cub and no oil leak. I wonder how long this newer gasket will last for a working cub; anyone care to guesstimate?

Re: replacing engine rear main seal

Mon Aug 26, 2013 8:43 pm

Groove Critter wrote:Hi John, It will be nice to have a fairly fixed up cub and no oil leak. I wonder how long this newer gasket will last for a working cub; anyone care to guesstimate?
I am expecting it to last for several years.

Re: replacing engine rear main seal

Tue Aug 27, 2013 7:17 am

John, too bad we didn't do this at MidMo's Cubfest in May. Splitting a tractor is easier with helping hands.

I realize the leak wasn't that bad (or at all) in May, but we would have loved to help. :)

Re: replacing engine rear main seal

Tue Aug 27, 2013 8:59 am

Thanks, but it is not that big a deal with the right tools and experience. Spent about hour and a half Sunday afternoon and got it to the point of unbolting torque tube. About 3 hours yesterday, which included checking clutch fingers, oiling generator, as well as other normal maintenance and a little rest, at which time my back said it was time to quit. All that is left to do now is put the hood back on, which I plan to do this afternoon.