Hydraulics on my deere 190e are jumpy?

[sdc23_99]

I recently purchased a 96 190e with about 6000hrs on it. I was operating it the other week and noticed when I was tracking it started lurching forward a bit, not as smooth as it had been running. I stoped operating, examined the machine and found that one small hose going from valve under center of the machine to the right track drive was leaking and hydraulic fluid was low. I took the hose off, brought it to have a new one made up and grabbed a bucket of hydraulic fluid at tractor supply. I put the new hose on, filled the hydraulic reservoir to just a bit over the full line and started it back up.
Since I replaced the hose, the hydraulics will become jumpy after operating for about 1/2 hour? They start off very smooth, then it feels as if there is air in the system and it is losing prime, all of the functions are affected. I tried cycling all of the cylinders to bleed any air out but the only thing that helps is parking the machine and letting it cool down.
Yesterday I removed a little hydraulic fluid because it was slightly high, that seemed to help a bit, but after a while it does the same thing. I did bleed the air out of the hydraulis pump behind the motor, but didnt help. Also, all of the hydraulic hoses look good except one on the arm cylinder is leaking very slightly. I thought maybe there was air trapped in the system but it seems like maybe it is allowing air to enter the system once it is warmed up. Could the one seeping hose allow air in? I have spent the past two days looking at everything I could think of on the machine, thought I had it figured out after I took a little fluid out, it ran perfect for 45min this morning but then started acting up again?
Any help or suggestions on what to investigate next would be greatly appreciated!!!

 

[buckfever]

Check the hose that goes from the tank to the pump. We had a clamp come loose and it wouldn't leak any fluid but would suck air. Just tighten a clamp and propblem fixed.

 

[stondad]

I hope that buckfever is right.

I'm not familiar with the particular machine but this may help:-

How much oil did you have to add? Was it the right grade?

Does the machine have a tank pressurised by air and is that ok? Otherwise it will be just relying on pressure building as the machine warms up. Either way, you may have disturbed something at the filler that is preventing the tank from building pressure.

The fact that the problem occurs after you have worked for a while, instead of when it is cold is tricky and may well hold the secret. The only answers that fit the facts is that you have bought dodgy oil that is foaming or an air leak as buckfever describes, aerating the oil after a while.

Good luck!

 

[sdc23_99]

Thanks for the replies, I'm gonna check and tighten the hoseclamps going to the pump inlet side today and will see if that solves the problem. I used the machine for a couple hours yesterday, it only happened a couple times and fixed itself after cycling the hydraulic cylinders?