Hydraulic oil foaming after new filter and replacement of fluid.

[Campinman]

I’ve just changed my hydraulic fluid, (which in a hustler is oil and I used the oil my dealer told me to for my mower) and I also changed the filter. I have done this many times before and never really noticed any foaming . Maybe I did not follow the procedure exactly. ( ie messed up a step)
But I’m getting a lot of foaming in the reservoir after I finished and ran the Mower for a bit. It runs fine and the pumps are not noisy. Could this be normal and the air/foaming will just go away Because there was just some trapped air in there when I did the procedure. Please can anyone give advice or some information? thanks much.

 

[ILENGINE]

Is it actually foaming like increasing in volume and trying to boil out, or just aerated from trapped air in the system. I would lean toward just aerated oil and will clear up after a couple of uses.

 

[Campinman]

Is it actually foaming like increasing in volume and trying to boil out, or just aerated from trapped air in the system. I would lean toward just aerated oil and will clear up after a couple of uses.

Hey thanks much! Sure hope u r correct.

 

[Tiger Small Engine]

Hey thanks much! Sure hope u r correct.

Make sure you have purged the hydro system completely. If you followed the correct procedure and opened both bypasses and ran steering arms forward and backwards and then closed bypasses and ran it again, with wheels off the ground, it should be purged. Otherwise, with air still present it will cause aeration of hydro oil which is not good. Keep an eye on it.

 

[Campinman]

Make sure you have purged the hydro system completely. If you followed the correct procedure and opened both bypasses and ran steering arms forward and backwards and then closed bypasses and ran it again, with wheels off the ground, it should be purged. Otherwise, with air still present it will cause aeration of hydro oil which is not good. Keep an eye on it.

I’m going to do

Make sure you have purged the hydro system completely. If you followed the correct procedure and opened both bypasses and ran steering arms forward and backwards and then closed bypasses and ran it again, with wheels off the ground, it should be purged. Otherwise, with air still present it will cause aeration of hydro oil which is not good. Keep an eye on it.

Thanks, im going to do the procedure again to b sure.

 

[Campinman]

Make sure you have purged the hydro system completely. If you followed the correct procedure and opened both bypasses and ran steering arms forward and backwards and then closed bypasses and ran it again, with wheels off the ground, it should be purged. Otherwise, with air still present it will cause aeration of hydro oil which is not good. Keep an eye on it.

OK I just did the procedure again and then took it out for a little spin and it’s fine. Must’ve just been some trapped air in there when I first did it and when it bubbled out it foam up there is zero foam in there now.

 

[Tiger Small Engine]

OK I just did the procedure again and then took it out for a little spin and it’s fine. Must’ve just been some trapped air in there when I first did it and when it bubbled out it foam up there is zero foam in there now.

Very good to hear. Aeration and cavitation are destructive to hydraulic pumps. People can do some further reading on the subject as needed.