Bobcat 310 1980 Hydraulic help

[2LateIWon]

If you are like me and would rather watch a video Ill post one below instead of reading. Im at a loss on what to do.
Ok so Long story short I bought this 2 years ago. The Previous owner said it just needed a new hydraulic pump. So I sourced and got a new one put on. I changed the hydraulic filter. Started it up and it was really jumpy like it had a bunch of air in it but instead of getting better it kept getting worse. I changed out all oil and tried to the best of my ability to clean the screen even forcing air backwards to help clear it out and make sure it was clear. Replaced the hoses and its still doing the same thing.
Greatful for any help. Please watch the video completely as I feel this was the best way to explain and show what was happening.
Video of whats going on

 

[bobatack]

The belt for the pump seems very loose
Also looks like the pump is not spinning very fast while trying to lift boom or bucket curl
A video from other side of machine watching the pump pulley would confirm that idea a little better

 

[Arny L]

What happens if you increase RPM. The old pump attachment marks are higher up on the bracket than were its sitting now, maybe the belt is slipping.

 

[2LateIWon]

The belt for the pump seems very loose
Also looks like the pump is not spinning very fast while trying to lift boom or bucket curl
A video from other side of machine watching the pump pulley would confirm that idea a little better

Yeah the belt doesn't slip unless bottomed out. Once I get this situation figured out I'll do better on belt traction

 

[2LateIWon]

What happens if you increase RPM. The old pump attachment marks are higher up on the bracket than were its sitting now, maybe the belt is slipping.

Yeah I've tried increasing rpms and it didn't seem to change anything

 

[Arny L]

To rule out suction side, you could drain off a couple of gals of hydraulic fluid from reservoir, and make up suction line to draw from 5 gal pail, if it corrects your problem, then it could be in tank. does it drive ok

 

[2LateIWon]

To rule out suction side, you could drain off a couple of gals of hydraulic fluid from reservoir, and make up suction line to draw from 5 gal pail, if it corrects your problem, then it could be in tank. does it drive ok

Interesing I like this setup. I might have to give it a try. Thanks
The drive is set up with clutches and chains and is not hydraulicly controlled but does drive perfectly.