Case 420 Backhoe Hyd. Pump

[tiresntracks]

I'm working on a 1957 Case 420 with a loader and a hoe. It seems to have about half the digging power it should. Someone replaced the hydraulic pump with one that I haven't indentified yet. I think it is probably too small. The book says the pump is supposed to put out 20 gpm and 2000 psi at 1900 rpm on a tractor with a loader only. I think one with a hoe and loader should have a bigger pump. Does anyone know what size it should be?

 

[BrianA]

The 20 gpm is about right for it I had an old 580 CK that had a 20 gpm pump. Lots of luck finding a pump that will fit it. The 580 had a Cesna pump on it. You might be able to reconfiger the drive on the front to a newer version like the CK model. If you are having trouble with the hoe part you could check the main relief valve on the spools on the backhoe part. There is also a main relief valve on the bucket controle up front if you are having problems on the loader end.

 

[tiresntracks]

Thanks for the info. Brian. I'll check all the relief valves first and then the pump. I think the book has the settings for the relief valves. The loader seems to have a little more power than the hoe, but still not much.