Hydraulic Leak

I have a 1951 Farmall Cub and it has started to push hydraulic oil into the crankcase. This just started this season. How can I fix this? No one around here has an answer Thank you

Depending on the model of the pump (IH used more than one), you need to replace the o-ring or seal on the shaft. Remove the pump and it will be self explanatory. If the shaft has a significant groove in it, it needs a speedi- or redi-sleeve (trade names). If it has an o-ring, take the pump to a machinest and have the hole the shaft goes thru enlarged to accept the sleeve.

Farmall Bob,

Here's some pics of mine, on a Super-A, and I don't know if the same pump and arrangement is used on a Cub, but the principles should be similar.
Here's my pump as it sits on the lower right engine case- you can find yours by following the hydraulic lines. My pump body separates into 2 pieces, and the offending O-ring (or seal,- different pumps used different ways to hold the hydraulic fluid) is in the front part of the body, arrowed.



Once off, here's the gear that extends into the engine case and is driven by the cam gear in the engine, and here is where your fluid is getting past and into the engine. The arrow points to where the washer under the nut was bent up, to act as a 'lock' on the nut.



Here's mine in pieces. (Warning- if you're going to take yours apart, make sure you have things go back in exactly from where they came out) As you can see, that outer gear is keyed, and needs to come off to extract the shaft (black arrow) on which it rides. The worn O-ring/seal is in the bore labeled #2. What CNKS was referring to is that the old O-ring/seal often wore a groove in the shaft, and you would see that groove where arrow #1 is pointing. A groove will promote leakage on your new O-ring/seal, so you don't want to miss it.



I'm holding the re-build kit I got from IH. It contains instructions with pictures. To get the right kit, you have to find the serial number on your pump. Mine was long, but very small, and I had to scrape paint to find it.

Any other questions?