Case 646 Lacking Hydraulic power help needed

[gtor72]

Hello all, I am a new owner of a Case 646 Tractor,
I am having a problem with lack of hydraulic power, I have had a new banana plate made (having a few extra made also) and fixed the forward reverse problem, I now have excellent travel in the control valves and good forward and reverse speed.
The problem I am having is when trying to use the loader moving forward it will not lift and move forward at the same time, in fact the loader bucket will slowly go down when trying to lift and move forward.
I am thinking its time to change all the oil over to rotella 15-40
I have no idea of the history of this machine, the loader works as it should when sitting still, but i could not even scoop up a rock yesterday that maybe weight 100lbs, could not go forward and lift at the same time.
any opinions? am i on the right track to consider changing all the oil?
appreciate any help. Mike

[duby13]

Hello, Mike. I don't have any experience with the 646 Case machines, but I do own a 446 & 448 garden tractor (one each). My 446 was doing something very similar. It would drive along just fine but the engine would bog down and the tractor would slow down for a second if I tried to lift the mower deck while driving. When I started mowing this year, it was losing wheel power going uphill. I parked it and went inside for dinner. When I came out, it started but stalled immediately when I moved the travel lever. When I tried to restart it, the engine wouldn't even turn over. I separated the engine from the pump, and the pump would not turn. I took the pump apart and pulled out what was left of the gears. There were also a lot of shavings inside the pump housing and I could see where the pump gears had cut into the housing (probably due to worn pump shaft bushings), and I think that this was leading to lower hydraulic pressure. The 448 has never exhibited this behavior.

I'm not sure exactly what you are calling the "banana plate". My far-from-expert opinion is that you will need to replace the pump.