cub rear main seal

Tue Apr 20, 2004 6:43 pm

I just finished spliting the cub to replace a rear main seal that I put together using the original retainer and a new seal that was leaking. The new seal went into the new retainer much harder than using the old retainer & new seal. But here is the problem, the new seal doesnt seem to fit around the crankshaft tightly. The seal is the correct part number. The seal that I took off fits the crank very snug, the new slides over the crank easily. Any suggestions? Thanks Mike

more info

Tue Apr 20, 2004 6:56 pm

The seal that I put in that was leaking was a after market seal, the new seal I'm installing is from case nh. I just don't want to split the tractor again for another leak any help would be great. Thanks Mike

Wed Apr 21, 2004 9:32 am


Sounds like it's not the right seal. If there is a number on the old seal take it to Napa or another auto parts store and see if they can match it. Mic your crank end and the seals they have. That should tell you if it will fit right. The seal should be a little smaller than the shaft. Maybe somebody turned the crank at one time.

Wed Apr 21, 2004 3:38 pm

I got a seal from NAPA and it was perfect replacement.

The seal needs to be tight on the shaft - that's how it holds the oil in when the shaft is turning. Make sure you use a little litheum grease on the shaft to help slide on the seal and set the seal when you first start the engine.

cub rear main seal

Wed Apr 21, 2004 8:05 pm

Thanks for the replys. Here's what I found.Yes the crank had been turned to .010 under at the last rebuild. The seal that I had purchased, fit the crank tightly it just leaked oil around where it went into the retainer.Looking at both seals they had aprox. the same inner diameter. But one seal would slide on the crank much easier. My next step I switched the spring that holds the tension on the seal. When I had both springs off the seals I found one spring to be slightly smaller"on the seal that went on tightly"after installing it on the loose fitting seal it became a tight fitting seal.I think problem solved. I installed the new seal with the tight spring. The cub will be going back together tomorrow.
The lesson I learned here is when a seal goes into it's retainer to easy it will leak. I still remember installing that seal and thinking something wasn't right, but I wanted to see the cub running. Thanks for the help. Mike

Wed Apr 21, 2004 8:54 pm

Hi Mike
It sounds like you found the fix, Good Luck !! I hope it works out, and THANKS for the knowledge. Paul K. inN.H.