I have a hydraulic leak where the last Eaton hydrostatic pump and the main hydraulic pump(loader function) bolts together. I separated the pumps and the entire void between the two was full of oil. There is a large diameter o-ring that seals the two pumps together. So do I have an internal leak on one of the pumps or just a bad o-ring between the two pumps? Is this normal and part of the case drain system? Thanks, Steve
Those are typically a "wet mount" and often the gear pump won't even have a shaft seal. Guessing you have either a bad mount o-ring or a very small crack in one housing or the other. High case drain pressure from excessive internal leakage or perhaps a clogged oil cooler can also lead to leakage at any weak point.
I would think there is a shaft seal on the pump that needs replacing. Before pulling the pump apart do a case drain pressure/ flow test . A worn pump could be the cause of the seal failure.
Learning as I go on this. Shocking to see oil where you don't expect it. The gear pump does have a seal. But it does not appear to leaking. The oil was coming from the hyrostatic pump. It appears to be a wet mount(thanks Lantraxco) as there is no seal on the shaft. I also found a passage(hard to see) that appears to flow oil. I will change the o-ring between the two pumps for now and see if that works. As big as the pump bodies are, I was surprised to see such a small cross section diameter on the o-ring. Tones- I will check the pressures, thanks.
Hoping someone recognizes the model of this pump? I would like to find a repair/parts manual. It was build around the year 2000. Also want to confirm it is a "wet mount". It looks like the shiny metal around the shaft is a needle bearing and not a seal? Is the hole in the casting(12 O'clock position) a case pressure passage? Thanks!
Looks like a cessna. Why would there be a rear seal? Even if there was no rear pump it would have a blocking plate.
Mike, Since I don't know anything about this pump my question is should there be oil on the output shaft? Are you saying oil is suppose to flow around the end of the output shaft and the gear pump makes the seal? Basically I need to know if I need to fix this pump or is it working as designed. Steve
Looks to me like there's no shaft seal required as there is no way of retaining it and you can't have a seal on a splined shaft. Maybe an O ring in the spigot is all that's needed.
It's fine, that hole is indeed designed to ensure that oil fills the cavity. Wet splines are rated for at least double the torque of dry splines and they live practically forever so they use the wet mount. Inspect the gear pump closely for cracks in the mounting flange, if you can't see anything clean the sealing areas up, reassemble with a new seal ring, o-ring or flat ring, not sure, should be okey-dokie.