Hydraulic pump

[sviennadan]

What are the chances that there would be hydraulic fluid leaking into the crankcase oil? When running, my Cub would lose hydraulic fluid, yet GAIN crankcase oil level.

[Jim Hudson]

There is a very good chance. Kit is available from CIH. Just some o rings you can buy local.

[John *.?-!.* cub owner]

As Jim said, it's a common problem. Later pumps used an oring at the front, but earlier ones used a regular oil seal. If yours happens to use the seal the ih part number is 355742R91, or National 471526

[cityofc]

It happened to me. The hydraulic level would keep dropping with hardly any leakage. I found out when I checked the oil level (boy was it full) where it was going. I ended changing the seals between the hydraulics/crankcase and that solved the problem. Other than draining hydraulic fluid, it was a fairly easy fix.

[sviennadan]

Thanks! I'm glad it's an easy fix. I have the hydraulic fluid drained right now anyway, so I'll pick up the seal or gasket, whichever I need, once I remove the pump and determine which I need. You guys are great for such good timely advice. I always learn something new, every day that I log on to the Forum!

[Paul Stav]

I just had the same trouble with a C tractor, and I would guess the pumps are about the same. I put in a new seal, but it did not work, the problem continued and I had to buy a new pump. The Case/IH man indicated that the seal toward the crankcase was on the low pressure side and the only purpose of the seal was to keep contaniments out of the pump. The low pressure side is the "suck" side, so if just the seal was bad, it wouldn't leak anyway. He says that when the pump is worn out of tolerance, it puts pressure on the seal, and that seal was not designed for pressure. Just passing on info. Good luck!